Plectis Atlas
Search

↑ and ↓ move, Enter opens, Esc closes.

Reading view

Uniform excess charge for Coulomb molecules and the outer radius of neutral atoms

OpenAI, 24 September 2026

PDFTeX source

Part of family 263: The ionization and generalized ionization conjectures. Read it with its family

This page is converted from the paper’s TeX source. Atlas reconstructs statement numbers from the paper’s typesetting source (TeX). Use the original PDF if they differ. One figure is shown as a placeholder; see the PDF for it.

Abstract

We prove that a molecule with M fixed nuclei of real charges at least one and total nuclear charge Z strictly binds at most Z+CM electrons, where C is universal. The result holds for the full nonrelativistic Coulomb Hamiltonian with two spin states and arbitrary distinct nuclear positions. For neutral atoms with integer nuclear charge Z\ge1, the first ionization energy and, for every ground state, the radius outside which one half of an electron remains are each bounded above and below by positive universal constants.

1 Introduction

We prove a uniform bound on the number of excess electrons that fixed Coulomb nuclei can strictly bind. If there are M nuclei of total charge Z, that number is at most CM, with a constant independent of their charges and positions. For a neutral atom with integer nuclear charge, we also prove that the cost of removing one electron and the radius containing all but one half of an electron each stay between positive universal constants. These conclusions address the number of bound electrons, the first ionization energy, and the location of the outer electronic mass. Their proofs share the local screening estimates developed in this paper.

1.1 The model and the results

Fix M\ge1, distinct positions R_1,\ldots,R_M\in\R^3, and real charges z_1,\ldots,z_M\ge1. Put

Z=\sum_{j=1}^M z_j,\qquad \nu=\sum_{j=1}^M z_j\delta_{R_j}, \qquad K(x)=|x|^{-1},\qquad V=K*\nu.

For n\ge1 let \mathcal H_n=\bigwedge^nL^2(\R^3;\C^2), so that there are two electron spin states and antisymmetry exchanges spatial and spin variables together. The Hamiltonian is the self-adjoint operator associated with the closed, bounded-below Coulomb form on \mathcal Q_n=\mathcal H_n\cap H^1((\R^3)^n;(\C^2)^{\otimes n}):

H_n=\sum_{i=1}^n\left(-\frac12\Delta_i-V(x_i)\right) +\sum_{1\le i<j\le n}|x_i-x_j|^{-1}. \tag{1.1}

The nuclei are fixed; their mutual repulsion is a scalar independent of n and is omitted. Write E_n=\inf\sigma(H_n) and E_0=0. We say that sector n binds strictly if E_n<E_{n-1}.

Theorem 1.1 (Uniform excess charge). There is a universal finite constant C such that every nuclear system specified above and every integer n\ge1 satisfy

E_n<E_{n-1}\quad\Longrightarrow\quad n\le Z+CM.

Moreover, E_n=E_{n-1} whenever n>Z+CM. For one nucleus this gives n\le Z+C under strict binding, for every real Z\ge1. The same constant is independent of all charges and nuclear positions.

The positions may be arbitrarily close or far apart. The theorem resolves positively the excess-charge form of the ionization conjecture in this strict-binding formulation [7, 19]. Equality of adjacent energies does not by itself exclude a ground state at threshold; such threshold states are not needed here.

For the radius conclusion specialize to one nucleus at the origin with integer charge Z\ge1. Write H_{n,Z} and E(n,Z) when the nuclear charge needs to be displayed. If \Psi_Z is a normalized ground state of H_{Z,Z}, its spin-summed density is

\rho_{\Psi_Z}(x)=Z\sum_{\sigma_1,\ldots,\sigma_Z} \int |\Psi_Z(x,\sigma_1;x_2,\sigma_2;\ldots;x_Z,\sigma_Z)|^2 \,dx_2\cdots dx_Z,

where the integral is absent for Z=1. Its mass is Z. Define

R(\Psi_Z)=\inf\left\{r\ge0: \int_{|x|>r}\rho_{\Psi_Z}(x)\,dx\le\frac12\right\}. \tag{1.2}

Theorem 1.2 (Uniform outer half-electron radius). There are universal constants 0<c\le C<\infty such that, for every integer Z\ge1 and every normalized ground state of H_{Z,Z},

c\le R(\Psi_Z)\le C.

The existence of these ground states is included in Lemma 2.5. No uniqueness or spherical symmetry is assumed. The exterior mass in (1.2) stays fixed as Z grows; it describes outer electrons rather than a fixed fraction of the atom.

Corollary 1.3 (Two-sided first-ionization bound). For the full nonrelativistic Coulomb atom specified above, with integer nuclear charge Z\ge1, one-electron kinetic term -\Delta/2, and two electron spin states, write E_Z(n)=E(n,Z). There are universal constants 0<c\le C<\infty such that the first ionization energy of the neutral atom satisfies

c\le I_1(Z):=E_Z(Z-1)-E_Z(Z)\le C \qquad\text{for every integer }Z\ge1.

1.2 History and the scales of the problem

Simon’s atomic formulation asks whether N_0(Z)-Z stays bounded, where N_0(Z) is the first sector at which the energy equals every later sector energy [19, Problem 9]. Since the sector energies are nonincreasing and ultimately constant, this is the largest strictly binding sector used here. The corresponding molecular conjecture has the form N_c\le Z+CM [7, Section 2.1.2].

The early charge bounds already distinguished atoms from molecules. Lieb proved bounds linear in the total nuclear charge for fixed atoms and molecules, without requiring Fermi statistics [8]. For fermionic atoms, Lieb, Sigal, Simon and Thirring established asymptotic neutrality: the maximal strictly bound particle number N_c(Z) satisfies N_c(Z)/Z\to1 as Z\to\infty [9, 10]. Fefferman and Seco, and Seco, Sigal and Solovej, subsequently obtained quantitative sublinear bounds [2, 18]. Ivrii obtained further semiclassical charge bounds for atoms and heavy molecules under the hypothesis that each nuclear charge is comparable to the electron number, with improved exponents for atoms and for suitably separated nuclei [5, Theorem 5.2.1]. For explicit finite-charge estimates, Nam proved N_c(Z)<1.22Z+3Z^{1/3} [14]. More recently, Hundertmark, Pattakos and Schulz obtained N_c(Z)<1.1185Z+4Z^{1/3} for Z\ge4 [4]. These estimates supply useful quantitative control while leaving the uniform excess-charge assertion distinct.

For the full many-electron Schrödinger atom, Seco, Sigal and Solovej also obtained, for large Z, an upper bound for the neutral first ionization energy and a lower bound for an exterior-mass radius, both given by powers of the nuclear charge [18, Theorems 1 and 3]. Their radius leaves one expected electron outside, whereas (1.2) leaves one half. Their energy upper bound grows with Z, and their radius lower bound decays with Z. The upper bound in Corollary 1.3 establishes the usual boundedness assertion for I_1(Z) [22, Section 2]; the uniform positive lower bound is an additional conclusion.

The statistical theories introduced by Thomas and Fermi [3, 23] predict a particularly rigid exterior screening profile. Lieb and Simon established the variational theory and its leading large-charge energy and density limits [11, 12]. Uniform ionization bounds were proved in Thomas–Fermi–von Weizsäcker theory by Benguria and Lieb [1], and in reduced and unrestricted Hartree–Fock theory by Solovej [20, 21]. Solovej’s unrestricted Hartree–Fock analysis compares screened potentials through successive spatial scales and also establishes uniform bounds and asymptotics for outer-electron radii [21, Definition 1.2, Theorem 1.5, and Sections 10–13]. Those conclusions concern their stated variational models; the states in (1.1) may have arbitrary many-body correlations.

The bulk density limit lives on the length scale Z^{-1/3}, whereas the normalized mass outside the radius in (1.2) is 1/(2Z). Its vanishing fraction makes bulk convergence insufficient to prove Theorem 1.2. The fixed exterior-mass viewpoint is also central to the generalized ionization conjecture [22, Section 3].

Companion papers use the estimates developed here, with additional arguments, to obtain Thomas–Fermi asymptotics for full two-spin Coulomb atoms. The energy result sends the number of removed electrons to infinity while it remains negligible relative to the nuclear charge [15, Theorem 1.1]; the neutral-radius result first takes upper and lower large-charge limits at fixed expected exterior electron mass, and then lets that mass tend to infinity [16, Theorem 1.1].

The analytic ingredients have separate roles. The Lieb–Thirring kinetic inequality provides a positive coarse density bound, for which we use Rumin’s spectral-splitting argument [13, 17]. The exact Thomas–Fermi coefficient comes instead from coherent-state filling and Neumann eigenvalue counting, with explicit remainders. These constructions have classical antecedents in the semiclassical analysis of Lieb and Simon and in the coherent-state comparison of Solovej [12, Theorems III.10–III.13] [21, Lemma 8.2]. Spatial square partitions are the usual IMS localization; sector-valued localization for correlated states is systematically developed by Lewin [6, Proposition 3.1 and Example 3.3]. Our conditional core construction retains the removed positions and spins, so that the remaining correlated state can be compared with local trial electrons through its own screened field.

1.3 Obstacles and the common argument

Fixing the total electron number obstructs a local density comparison: a ball may contain too many or too few electrons, and its conditional core need not minimize any fixed local-particle-number problem. We therefore first work relative to the minimum E=\inf_{n\ge0}E_n over all sectors. A coarse binding bound guarantees that it is attained at a largest strictly bound sector. A normalized state with form energy at most E+\delta will be called a \delta-state. Keeping \delta visible makes local estimates available again after an event is imposed, after particles are deleted, and after a shell weight changes the probability law.

Three steps are common to the molecular and atomic conclusions. First, a spatial cut records every removed electron and leaves an antisymmetric conditional core. In the hole, arbitrary expected trial mass is allowed because each actual trial has an integer sector with energy at least E. The coherent upper and Neumann lower comparisons have the same kinetic coefficient. Their comparison produces a local Thomas–Fermi minimizer \rho and its screened field W, related by

\rho=k(W_+)^{3/2},\qquad k=\frac{2^{3/2}}{3\pi^2}.

It also controls the Coulomb discrepancy from the actual fine density and the energy of that density in the negative part of W. A bootstrap for the positive field closes a bound on the second moment of local electron counts.

Next, smoothing and noisy observations produce a conditional density \mu and a screened field. In the atomic case the field is H=V-K*\mu. On nucleus-free patches we transfer the local Thomas–Fermi law to these quantities, as one-sided comparisons between \mu and k(H_+)^{3/2} at positive, bounded rescaled heights. The molecular comparison retains the nearby nuclear potential explicitly: after splitting off its singular part, we compare the continuous conditional offset through an averaged Thomas–Fermi response.

To prove these comparisons, observe all positions with independent errors of width \ell and forget the particle labels. An observation event of probability p has a symmetric square-root likelihood multiplier. Applied to a sector eigenstate, its energy cost is bounded by C\ell^{-2}\log^5(e/p), without a particle-number factor. A hypothetical failure can therefore be tested by the local quantum estimates. The original observation posterior and the fresh patch posterior are different: two separate conditional-expectation identities compare their fields after averaging in the event law. The negative-field penalty controls the rare configurations needed to pass a lower field estimate to expectation.

Finally, a positive comparison field is continued outward. A local maximum chooses between a shifted nonlinear subsolution and a shifted observed field. The inverse comparisons let us replace the model reaction by the actual conditional density on one more layer. Conditional averaging then forgets one observation array, with convexity preserving the nonlinear inequality. The errors are summed through their expected integrals. At the terminal scale, comparison with a compact source potential and its spherical mean turns the positive field into a lower bound on the nuclear charge minus the enclosed electron mass, up to the accumulated error.

The geometry determines how this mechanism closes. For a molecule, the local length measures nearby nuclear charge. Empty nuclear annuli must be counted without a loss for their number of scales. A decomposition by nested nuclear representatives gives a total cost proportional to M; it bounds the electrons outside the terminal region and closes the excess-charge estimate.

For an atom, local balls away from the nucleus use their distance from it; this distinct scale reaches inside the bulk length. The continuation produces an interior electron deficit for sector ground states with n\le3Z and bounded energy offset from E. We first use it at offset zero. Deleting exterior particles then proves E_{Z-1}\le E+C, so both neutral and singly ionized ground states become eligible for the fixed-offset estimates. The neutral deficit gives the lower radius bound. A spatially averaged insertion into the singly ionized state gives a uniform positive gap E_{Z-1}-E_Z\ge c. Together with the offset bound this proves Corollary 1.3, after adjusting the constants at finitely many smaller charges. The gap also yields the expected tail bound C/R through a shell-weighted change of law. Here the shell weight is measurable in the revealed data, which is why this change of law preserves the surviving conditional field.

1.4 Organization and normalization

Section 2 provides the sector facts, and Sections 3–5 prove the shared localization, screening, and conditioning estimates. The two local geometries are specified in Section 4. From these shared tools, Sections 6–9 prove the molecular excess-charge bound. A reader interested in the neutral atomic results may instead proceed directly to Sections 10–14; these proofs do not use the molecular excess-charge theorem. The atomic comparison and intermediate subsolutions come first, followed by deletion, insertion, and the tail argument in the order described above. Section 15 collects the precise inputs for the companion asymptotic problems, including the classical Thomas–Fermi comparisons proved in Section 7.

All density integrals include spin summation. For a real number or function v, write v_+=\max(v,0) and v_-=\max(-v,0). The constants C,c>0 may change from line to line and are universal unless a dependence is stated. With the kinetic normalization in (1.1),

c_{\rm TF}=\frac3{10}(3\pi^2)^{2/3},\qquad k=(5c_{\rm TF}/3)^{-3/2}=\frac{2^{3/2}}{3\pi^2},\qquad c_F=4\pi k. \tag{1.3}

The coarse kinetic lower bound does not assert that its unspecified constant equals c_{\rm TF}.

2 A ground state at the minimum over all sectors

The local comparisons in the proof may replace electrons in a region by a different number of electrons. We therefore first reduce to a ground state whose energy is minimal among all particle-number sectors. A coarse number bound makes this reduction possible; no convexity of the sector energies is needed.

2.1 The Coulomb form and strict binding

Use the Hilbert spaces and form domains defined in the Introduction, writing n for a variable particle number. The quadratic form associated with (1.1) is

q_n[\psi] =\frac12\sum_{i=1}^n\|\nabla_i\psi\|_2^2 -\sum_{i=1}^n\int V(x_i)|\psi|^2 +\sum_{1\leq i<j\leq n}\int K(x_i-x_j)|\psi|^2. \tag{2.1}

We also evaluate this expression on the ambient spin-valued H^1 space when a localization preserves antisymmetry only within groups of variables. Sector-energy bounds will be applied only to the groups that remain antisymmetric. Hardy’s inequality in three dimensions, followed by Cauchy–Schwarz, shows that each Coulomb term is infinitesimally form bounded relative to the kinetic energy. For a pair term, apply the same argument to the relative coordinate x_i-x_j. Thus, for each fixed system and sector, the sum of the absolute Coulomb forms is bounded by

\eta\sum_i\|\nabla_i\psi\|_2^2+C_\eta\|\psi\|_2^2 \qquad(\eta>0).

Consequently (2.1) is closed and bounded below on \mathcal Q_n. Its associated self-adjoint operator is the Hamiltonian H_n in the Introduction, and

E_n=\inf_{\substack{\psi\in\mathcal Q_n\\\|\psi\|_2=1}} q_n[\psi]=\inf\sigma(H_n).

Smooth compactly supported antisymmetric functions form a form core: approximate in H^1 and apply the finite antisymmetrization projection. Set \mathcal H_0=\mathcal Q_0=\mathbb C, q_0=0, and E_0=0. The constants in these elementary domain facts may depend on the fixed system and on n.

Lemma 2.1 (Monotonicity and strict-binding compactness). For every fixed nuclear system, E_{n+1}\leq E_n for n\geq0, and E_1<0. If E_n<E_{n-1}, there is a normalized \Psi\in\mathcal Q_n with q_n[\Psi]=E_n.

Proof. Approximate an n-electron trial state by one with compact support. Wedge it with a normalized spin orbital in a disjoint distant ball. Dilate the orbital to make its kinetic energy small and separate the supports far enough to make the added repulsion small. Disjoint spatial supports make the energy of the normalized wedge the sum of the group energies and their direct cross repulsion. Dropping the added nuclear attraction proves E_{n+1}\leq E_n. A normalized orbital dilated about one nucleus has kinetic energy O(s^{-2}) and attraction at most -c z_m s^{-1}, proving E_1<0.

Suppose \Delta=E_{n-1}-E_n>0, and take a normalized minimizing sequence \psi_j. The form bound above gives a uniform H^1 bound. Choose nonnegative Lipschitz functions g_S,h_S with

g_S^2+h_S^2=1,\quad g_S=1\text{ on }B(0,S),\quad g_S=0\text{ outside }B(0,2S),\quad |\nabla g_S|+|\nabla h_S|\leq C/S.

They may be constructed as the cosine and sine of a cutoff angle. For each subset I of the particle labels, multiply \psi_j by \prod_{i\in I}g_S(x_i)\prod_{i\notin I}h_S(x_i). The squared norms of these localized states sum to one. The product partition identity for the kinetic energy adds at most Cn/S^2 to the sum of their forms.

The all-g_S component has energy at least E_n times its squared norm. If k<n coordinates carry g_S, slice in the remaining coordinates. Antisymmetry in the k retained coordinates gives their energy lower bound E_k\geq E_{n-1}. Drop the other kinetic terms and all pair terms involving an h_S coordinate. For S>2\max_m|R_m|, their total nuclear attraction is bounded below by -2Zn/S times the component’s squared norm. If p_j(S) is the total squared mass of components other than all-g_S, it follows that

(\Delta-2Zn/S)p_j(S) \leq q_n[\psi_j]-E_n+Cn/S^2.

The probability that any |x_i|\geq2S is at most p_j(S), because the all-g_S product vanishes there. Taking first j\to\infty, then S\to\infty, proves tightness.

Local Rellich compactness and tightness give, along a subsequence, strong L^2 convergence to a normalized antisymmetric \Psi, weak H^1 convergence, and almost-everywhere convergence. The attraction converges: the infinitesimal form bound applied to \psi_j-\Psi, with its relative-bound parameter subsequently tending to zero, gives

\sum_i\int V(x_i)|\psi_j-\Psi|^2\longrightarrow0.

Cauchy–Schwarz with this weight handles the difference of the attractive expectations. The kinetic energy is weakly lower semicontinuous, and the nonnegative repulsion is lower semicontinuous by Fatou’s lemma. Hence \Psi minimizes. Variation in the form domain gives the weak eigen-equation at E_n.

2.2 A coarse number bound

The following reciprocal-potential test is a weighted-electron argument of the type used in charge-linear ionization bounds [8]. We include the calculation, including the regularization needed for the form domain.

Lemma 2.2 (Reciprocal-potential bound). If E_n<E_{n-1} and every z_m\geq1, then n\leq3Z.

Proof. Let \Psi be the minimizer from Lemma 2.1. For l,\varepsilon>0 put

V_l(x)=\sum_m z_m(|x-R_m|^2+l^2)^{-1/2},\qquad U=V_l+\varepsilon,\qquad w=U^{-1}.

For these fixed parameters, w and its first derivatives are bounded. Test the weak eigen-equation with (\sum_iw(x_i))\Psi and take real parts. This summed multiplier is symmetric; after taking this admissible test we may expand its individual summands in the ambient form.

In the ith summand, the Hamiltonian on the other n-1 coordinates, minus E_n, has nonnegative pairing after weighting by w(x_i). This follows by slicing in x_i and its spin and using E_{n-1}\geq E_n. The remaining kinetic pairing is also nonnegative. Indeed, with \phi=w(x_i)\Psi,

\begin{align*} \operatorname{Re}\int\nabla_i\Psi\cdot \overline{\nabla_i(w(x_i)\Psi)} &=\int U(x_i)|\nabla_i\phi|^2 -\frac12\int(\Delta V_l)(x_i)|\phi|^2\geq0,\\ \Delta V_l(x)&=-3l^2\sum_m z_m(|x-R_m|^2+l^2)^{-5/2}\leq0.\end{align*}

The integration by parts is justified by large-radius cutoffs and H^1 approximation; all displayed coefficients and their needed derivatives are bounded for fixed l,\varepsilon. We obtain

\E_\Psi\sum_{i<j}\frac{w(x_i)+w(x_j)}{|x_i-x_j|} \leq\E_\Psi\sum_iw(x_i)V(x_i). \tag{2.2}

Let l\downarrow0 at fixed \varepsilon. Dominated convergence applies, using V/\varepsilon for attraction and 2K/\varepsilon for a pair. These functions have finite expectations on the form domain. Hence (2.2) holds with w=(V+\varepsilon)^{-1}, and its right side is at most n.

For a configuration outside the null set of nuclear collisions, set

q_{im}=\frac{w(x_i)z_m}{|x_i-R_m|},\qquad s_i=\sum_mq_{im}=\frac{V(x_i)}{V(x_i)+\varepsilon}\leq1.

The triangle inequality gives

\frac{w(x_i)+w(x_j)}{|x_i-x_j|} \geq\sum_m\frac{q_{im}q_{jm}}{z_m}.

In fact, multiplying the right side by |x_i-x_j| bounds it above by w(x_i)w(x_j)(V(x_i)+V(x_j))\leq w(x_i)+w(x_j). Weighted Cauchy–Schwarz and z_m\geq1 now imply

\begin{align*} \sum_{i<j}\sum_m\frac{q_{im}q_{jm}}{z_m} &=\frac12\sum_m\frac{(\sum_iq_{im})^2-\sum_iq_{im}^2}{z_m}\\ &\geq\frac{(\sum_i s_i)^2}{2Z}-\frac n2.\end{align*}

Here \sum_mq_{im}^2/z_m\leq\sum_mq_{im}^2\leq s_i^2\leq1. As \varepsilon\downarrow0, each s_i tends to one almost surely, and the squared sum is bounded by n^2. Taking expectations in the last inequality and using (2.2) gives n\geq n^2/(2Z)-n/2, as asserted.

Lemma 2.3 (Reduction to a global sector minimum). For every fixed nuclear system there is a largest integer N such that E_N<E_{N-1}. It satisfies N\leq3Z, has a normalized minimizer \Psi, and

E:=E_N=\inf_{n\geq0}E_n. \tag{2.3}

Any bound on this N bounds every strictly bound sector of the same system.

Proof. The set of strict sectors is nonempty since E_1<0, and finite by Lemma 2.2. After its largest member there are no strict drops. Monotonicity therefore gives E_n=E_N for n>N, whereas E_n\geq E_N for n<N. Existence of \Psi follows from Lemma 2.1. Every other strict sector has particle number at most N.

For each fixed nuclear system put E=\inf_{n\ge0}E_n. A \delta-state is any normalized \psi\in\mathcal Q_n in a finite sector n with q_n[\psi]\le E+\delta, where \delta\ge0. Expectation in the squared law of a state includes the spin sum; when only positions are observed, particle labels are retained unless an unordered observation is explicitly specified.

Lemma 2.4 (Energy cost of a multiplier). Let \Psi\in\mathcal Q_n be a normalized eigenstate with eigenvalue e_\Psi. If F is a bounded real Lipschitz function of the spatial configuration, invariant under particle permutations, then

q_n[F\Psi]-e_\Psi\|F\Psi\|_2^2 =\frac12\E_\Psi|\nabla F|^2. \tag{2.4}

Here \nabla denotes the full spatial gradient in \R^{3n}.

Proof. Both F\Psi and F^2\Psi belong to \mathcal Q_n. Test the weak eigen-equation with F^2\Psi and expand the gradients. Subtraction from q_n[F\Psi] cancels all multiplication potentials and mixed-gradient terms, leaving (2.4).

2.3 Atomic sectors and neutral ground states

In the atomic specialization M=1, R_1=0, and z_1=Z, we write E_n=E(n,Z). The compactness proof of Lemma 2.1 applies to every normalized minimizing sequence, so the set of normalized ground states of a strictly bound sector is compact in L^2.

This is Zhislin’s atomic binding condition n<Z+1 [24, 25], specialized to integer Z. We give the proof needed here.

Lemma 2.5 (Atomic binding). For integer Z\ge1, E_n<E_{n-1} for 1\le n\le Z. Each of these sectors has a ground state, and every normalized minimizing sequence has an L^2 convergent subsequence with normalized ground-state limit. The multiplier identity of Lemma 2.4 holds for every such ground state with e_\Psi=E_n.

Proof. Strict binding follows inductively beginning with the vacuum. Suppose \Phi is a ground state in sector n-1. With the radial core cutoff g_S used in the compactness proof, put F_S=\prod_i g_S(x_i). Its norm tends to one, and the multiplier identity gives normalized energy E_{n-1}+O_Z(S^{-2}). Wedge this state with a normalized radial spatial orbital of fixed spin, supported in 3S<|x|<4S, with kinetic energy O(S^{-2}). The supports are separated. Newton’s spherical mean identity is

\frac1{4\pi}\int_{\mathbb S^2}|s\omega-x|^{-1}\,d\omega =\frac1{\max(s,|x|)}. \tag{2.5}

It follows directly by integrating (s^2+|x|^2-2s|x|t)^{-1/2}/2 over -1<t<1. Every core radius is at most 2S, so the added electron’s attraction plus direct repulsion is at most -(Z-n+1)/(4S). For n\le Z this strictly dominates the kinetic and cutoff errors when S is large. Lemma 2.1 supplies the next ground state. Its tightness argument gives the asserted compactness for every minimizing sequence, completing the induction.

Lemma 2.6 (A minimum over all sectors). Every strict sector, namely every n with E_n<E_{n-1}, satisfies n\leq2Z+1. There is consequently a largest strict index N_*, and

Z\leq N_*\leq2Z+1\leq3Z, \qquad E:=\inf_{n\geq0}E_n=E_{N_*}. \tag{2.6}

The infimum E is attained by a normalized ground state in sector N_*.

Proof. Let \Phi be a ground state in a strict sector, supplied by Lemma 2.1. For l,\eps>0 set

U(x)=(|x|^2+l^2)^{-1/2}+\eps,\qquad w(x)=U(x)^{-1}.

For fixed parameters w and its first derivatives are bounded. Test the weak eigen-equation by (\sum_iw(x_i))\Phi and take real parts. This is a symmetric admissible multiplier. In its ith summand, the form on the other n-1 coordinates is at least E_{n-1}\E_\Phi w(x_i), by slicing in x_i and its spin. The selected-coordinate kinetic pairing is nonnegative. Indeed, writing \phi=w(x_i)\Phi and hence \Phi=U(x_i)\phi, integration by parts gives

\begin{align*} \operatorname{Re}\int\nabla_i\Phi\cdot \overline{\nabla_i(w(x_i)\Phi)} &=\int U(x_i)|\nabla_i\phi|^2 -\frac12\int\Delta U(x_i)|\phi|^2\geq0,\\ \Delta U(x)&=-3l^2(|x|^2+l^2)^{-5/2}\leq0.\end{align*}

The identity follows first for smooth compactly supported functions; the bounded coefficients for fixed l,\eps, approximation in H^1, and large-radius cutoffs give it in the present domain. Since E_{n-1}-E_n>0, discarding that additional nonnegative term leaves

\E_\Phi\sum_{i<j}\frac{w(x_i)+w(x_j)}{|x_i-x_j|} \leq \E_\Phi\sum_i w(x_i)\frac Z{|x_i|}. \tag{2.7}

Let l\downarrow0 at fixed \eps. Domination by 2K(x_i-x_j)/\eps for pairs and V(x_i)/\eps for attraction, which are integrable on the form domain, justifies the limit. Then w(x)=|x|/(1+\eps|x|). As \eps\downarrow0, both sides increase and the right side tends to nZ. The left side tends to the expectation of \sum_{i<j}(|x_i|+|x_j|)/|x_i-x_j|, which is at least n(n-1)/2 by the triangle inequality. Thus n\leq2Z+1.

The strict indices form a nonempty finite set by Lemma 2.5. After its largest element N_* there can be no further strict drop; monotonicity implies E_n=E_{N_*} for every n>N_*. For n<N_* monotonicity gives E_n\geq E_{N_*}. This proves (2.6), without any assumption on possible plateaus before N_*. Attainment follows once more from Lemma 2.1.

3 Common localization and quantum comparisons

We next isolate the local variational tools. A spatial cut records the electrons removed from a region and leaves an antisymmetric conditional state for the others. Its conditional electrostatic field enters an exact energy identity. The state may belong to any finite particle-number sector. Because E is the minimum over all sectors, we may insert a variable number of trial electrons into the resulting hole. Upper and lower semiclassical comparisons will have the same kinetic coefficient

\cT=\frac3{10}(3\pi^2)^{2/3}.

An additional kinetic bound, whose coefficient need not be sharp, controls localization errors.

3.1 Coulomb energy and a kinetic bound

Write \dot H^1(\R^3) for the completion of C_c^\infty(\R^3) in the gradient norm, represented in L^6(\R^3) by Sobolev’s inequality. For a compactly supported real f\in L^{5/3}(\R^3), put

D(f)=\frac12\int f(K*f).

This definition allows signed f.

Lemma 3.1 (Coulomb duality and radial smearing). For compactly supported real f\in L^{5/3}(\R^3), its Coulomb potential is continuous and belongs to \dot H^1, and

D(f)=\frac1{8\pi}\|\nabla(K*f)\|_2^2, \qquad \left|\int fv\right|\leq C\sqrt{D(f)}\|\nabla v\|_2 \quad(v\in\dot H^1). \tag{3.1}

The potential and energy assertions also hold for a nonnegative f\in L^{5/3} whose distribution belongs to (\dot H^1)^*, with K*f defined by its nonnegative convolution. Its dual pairing with any v\in\dot H^1 is the absolutely convergent integral \int fv.

If \eta is a radial nonnegative probability density supported in B(0,b), then K*\eta\leq K, with equality outside that ball. In particular, D(\eta*\rho)\leq D(\rho) for every nonnegative compactly supported \rho\in L^{5/3}.

Proof. For compactly supported f\in L^{5/3} we also have f\in L^{6/5}. Riesz representation on \dot H^1 gives a unique solution u of -\Delta u=4\pi f. The convolution K*f is continuous: near the singularity use K\in L^{5/2}_{\mathrm{loc}} and continuity of translations in that space; away from it use dominated convergence. It is bounded locally and decays like O(|x|^{-1}) at infinity, hence belongs to L^6. It has the same distributional Laplacian as u. A harmonic L^6 function is zero, by mollification and the mean-value property on arbitrarily large balls. Thus u=K*f. Testing its weak equation with u gives the first identity in (3.1); testing with v and using Cauchy–Schwarz gives the second.

For the noncompact nonnegative case, positivity first gives

\int f|\varphi|\leq\|f\|_{(\dot H^1)^*}\|\nabla\varphi\|_2 \qquad(\varphi\in C_c^\infty).

To obtain this estimate, approximate the absolute value by smooth convex truncations with derivative bounded by one. Completion and an almost-everywhere convergent subsequence extend the estimate to \dot H^1 and identify its dual pairing with actual integration. Let u be the Riesz solution, and let u_j=K*(\mathbf1_{B(0,j)}f). Testing the difference equation with (u_j-u)_+ gives u_j\leq u. These positive-part tests belong to \dot H^1: an L^6 function with gradient in L^2 is in the completion by large-radius cutoff and mollification. For the cutoff error, Hölder’s inequality bounds the gradient of the cutoff times the function by its L^6 norm on the escaping annulus. Now u_j\uparrow K*f and u_j\leq u\in L^6, so dominated convergence in L^6, the distributional equation, and harmonic uniqueness give K*f=u. Its energy identity follows by testing with u. The convolution is continuous also in this case. Choose a point x_0 where its value is finite. On any fixed bounded set of evaluation points, the sufficiently distant kernel tails are dominated by a constant times K(x_0-\cdot)f, which is integrable. Dominated convergence handles that tail, and the local L^{5/3}–L^{5/2} argument handles the remaining compact part.

The spherical average of K at distance d from a sphere of radius s is 1/\max(d,s), by direct angular integration. Decomposing a radial probability into spherical averages proves the smearing assertion. The difference of two independent radial displacements is again radial; applying the same assertion to its distribution and integrating against \rho(x)\rho(y) proves the energy inequality.

For a positive trace-class operator \gamma on L^2(\R^3;\mathbb C^2), write \rho_\gamma for its spatial density, with spins summed. Its kinetic energy is \operatorname{Tr}(-\Delta/2)\gamma, defined by the nonnegative form. We use the Lieb–Thirring kinetic inequality [13] in the following non-sharp form. The short proof by spectral projections also follows the distribution-energy approach of Rumin [17].

Lemma 3.2 (Occupation and kinetic energy). If 0\leq\gamma\leq1 has finite trace, then

\operatorname{Tr}(-\Delta/2)\gamma \geq c\int\rho_\gamma^{5/3} \tag{3.2}

for a universal c>0. The one-body density matrix of an antisymmetric k-particle vector f is bounded above by \|f\|_2^2 times the identity. The same bound holds after integration in auxiliary variables, and such matrices may be summed whenever the corresponding squared norms sum to one.

Proof. For a unit spin orbital v, the number operator \sum_{i=1}^k|v\rangle\langle v|_i is a projection on the antisymmetric space: in a Slater basis containing v, its eigenvalue is zero or one. Its expectation is at most \|f\|_2^2. This proves the occupation assertion and its versions with auxiliary integration and mixtures.

For the kinetic bound, take an eigen-expansion \gamma=\sum_\alpha\lambda_\alpha |u_\alpha\rangle\langle u_\alpha|, and let P_s be Fourier projection onto |p|^2/2\leq s. The density of its low-frequency parts is at most Cs^{3/2}: Bessel’s inequality bounds each spin evaluation against the corresponding Fourier vector, and there are two spins. The triangle inequality in the weighted orbital-index and spin norm gives, almost everywhere,

\sum_{\alpha,\sigma}\lambda_\alpha |((1-P_s)u_\alpha)(x,\sigma)|^2 \geq\big(\sqrt{\rho_\gamma(x)}-Cs^{3/4}\big)_+^2.

Integrating the left side in x and then in s>0 gives the kinetic trace by Plancherel and the layer-cake formula. The integral of the right side in s is a positive constant times \rho_\gamma(x)^{5/3}. Truncation proves the assertion also when the kinetic trace is infinite.

Lemma 3.3 (Global atomic density at an energy offset). For one nucleus of charge Z\ge1, every \delta-state in a sector n\le3Z satisfies

\int\rho_\psi^{5/3}\le C(Z^{7/3}+\delta). \tag{3.3}

Proof. Drop the nonnegative pair repulsion, use E\le0, and split attraction at R=Z^{-1/3}. Outside that ball it is at most Zn/R\le3Z^{7/3}. Inside, Young’s inequality gives

\int_{|x|<R}\frac Z{|x|}\rho_\psi \le\frac c2\int\rho_\psi^{5/3} +C\int_{|x|<R}(Z/|x|)^{5/2} \le\frac c2\int\rho_\psi^{5/3}+CZ^{7/3},

where c is the constant in Lemma 3.2. Combine this with that kinetic lower bound and the energy bound q_n[\psi]\le E+\delta\le\delta.

3.2 Cuts, conditional states, and the exact energy identity

The underlying tools are the IMS formula [21, Lemma 2.4] and localization into correlated particle-number sectors [6, Proposition 3.1 and Example 3.3]. Here we retain the removed coordinates as data, so that their conditional core field remains available in the exact energy identity.

Consider a finite sequence of deterministic nonnegative Lipschitz functions (s_h,c_h) on \R^3, with s_h^2+c_h^2=1. At stage h the factor s_h removes particles from what remains of the core. Define the first-out factors and the final core factor by

p_h=s_h\prod_{l<h}c_l,\qquad c=\prod_hc_h, \qquad o=\Big(\sum_hp_h^2\Big)^{1/2}. \tag{3.4}

Thus o^2+c^2=1. For a normalized \psi\in\mathcal Q_n and I\subset\{1,\ldots,n\}, put

\psi_I=\prod_{i\in I}o(x_i)\prod_{i\notin I}c(x_i)\psi.

Under the squared laws of these functions, whose total mass is one, record I and the positions and spins of its out particles. Decorate each such particle with stage h with probabilities p_h^2/o^2 at its position. Denote the resulting data by X.

Given X, normalize the slice in the remaining core variables. It is an antisymmetric form-domain state almost surely. Write e_X for its energy, \rho_X^c for its one-body density, and

\Phi_X=V-K*\rho_X^c.

For the vacuum slice set e_X=0 and \rho_X^c=0.

Lemma 3.4 (Conditional localization identity). With the preceding definitions, set

T_o=\frac12\sum_I\sum_{i\in I}\|\nabla_i\psi_I\|_2^2.

There is a nonnegative localization error satisfying

\mathrm{IMS}\leq\frac12\E_\psi\sum_i\sum_h \big(|\nabla s_h|^2+|\nabla c_h|^2\big)(x_i) \tag{3.5}

such that

q_n[\psi]+\mathrm{IMS} =\E e_X+T_o-\E\sum_{i\ \mathrm{out}}\Phi_X(x_i) +\E\sum_{i<j\ \mathrm{out}}K(x_i-x_j). \tag{3.6}

The out kinetic energy satisfies

T_o\geq c\int(o^2\rho_\psi)^{5/3},

where \rho_\psi is the raw one-body density. Conditional quantities have versions jointly measurable in the data and the field evaluation point. Appending deterministic cuts admits a coupling in which these decorated data are nested, and hence conditional expectations of raw quantities satisfy the tower property.

Proof. Successive squared-gradient splitting gives

\sum_h|\nabla p_h|^2+|\nabla c|^2 =\sum_h\Big(\prod_{l<h}c_l^2\Big) (|\nabla s_h|^2+|\nabla c_h|^2).

The norm-map inequality bounds |\nabla o|^2 by \sum_h|\nabla p_h|^2. Expanding the product partition in the kinetic form, the mixed derivatives cancel because o\nabla o+c\nabla c=0. This proves the stated IMS bound. Multiplication potentials split exactly by the squared partition.

Fix the recorded subset I, and write u for its out positions and spins and \xi for the remaining positions and spins. Put

\kappa_I(u)=\int|\psi_I(u,\xi)|^2\,\mathrm d\xi, \qquad \chi_X(\xi)=\frac{\psi_I(u,\xi)}{\sqrt{\kappa_I(u)}} \quad\text{when }\kappa_I(u)>0,

where the integral includes the core spin sum. Thus \chi_X is the normalized core vector, with its phase retained. The stage decoration depends only on u and does not change this normalized slice. Fubini gives its H^1 regularity almost surely; permutations of core variables preserve the multiplying factors and therefore its antisymmetry. The conditional core–out repulsion is exactly

\sum_{i\ \mathrm{out}}\int K(x_i-x)\rho_X^c(x)\,\mathrm dx.

Grouping the core form, out kinetic form, and the remaining multiplication potentials proves (3.6). All absolute Coulomb terms and kinetic terms are integrable in this calculation by the form bounds and the finite partition. The slice ratios and their integrals give the stated measurable versions; assign arbitrary values on null slices.

For each I, apply the occupation assertion of Lemma 3.2 to the out group, integrating the other variables. Its one-body matrix \gamma_I^o obeys \gamma_I^o\leq\|\psi_I\|_2^2. Thus \gamma_o=\sum_I\gamma_I^o\leq1, even though the out particle number varies with I. Its kinetic trace is T_o, and its density is o^2\rho_\psi, by summing the squared partition with one label required to be out. Equation (3.2) proves the kinetic assertion.

Finally, the entire construction has a single sampling description. Conditional on the raw configuration, independently label each coordinate by its first-out stage or by final core, with probabilities p_h^2 and c^2. An appended cut only splits the previous core probability. Forgetting its new-stage labels and their variables recovers the old observation. This is the required nesting and proves the tower assertion.

3.3 Insertion of trial electrons

We use the coherent-packet construction [21, Lemma 8.2]. The next lemma turns a nonnegative density into a genuine fermionic trial state. Its particle number is random, with integer values; the global sector minimum in (2.3) is what makes this permissible.

Fix once and for all a real smooth radial g supported in the unit ball, with \int g^2=1, and set g_b(x)=b^{-3/2}g(x/b).

Lemma 3.5 (Trial particles in a hole). Fix a conditional core slice with finite energy e_X and field \Phi_X as above. Let \rho\geq0 belong to L^{5/3} and have compact support. Suppose its packet region \operatorname{supp}\rho+\overline{B(0,b)} has positive distance from the spatial support allowed to the core particles. Then

E\leq e_X+\cT\int\rho^{5/3} +Cb^{-2}\int\rho -\int\Phi_X(g_b^2*\rho)+D(\rho). \tag{3.7}

The constant depends only on the fixed function g. The vacuum trial also gives E\leq e_X.

Proof. For each center y, momentum p, and spin \sigma, use the orbital

v_{y,p,\sigma}(x,\tau) =g_b(x-y)e^{ip\cdot x}\mathbf1_{\{\tau=\sigma\}}.

Integrate its projector over both spins and |p|\leq(3\pi^2\rho(y))^{1/3} with measure \mathrm dy\,\mathrm dp/(2\pi)^3, obtaining an operator \gamma. The unrestricted packet resolution is the identity: apply Plancherel in p and then integrate g_b^2 in y. Restriction therefore gives 0\leq\gamma\leq1. Momentum-ball integration gives

\begin{align*} \operatorname{Tr}\gamma&=\int\rho, &\rho_\gamma&=g_b^2*\rho,\\ \operatorname{Tr}(-\Delta/2)\gamma &=\cT\int\rho^{5/3} +\frac12\|\nabla g\|_2^2b^{-2}\int\rho. \tag{3.8}\end{align*}

The reality of g eliminates the kinetic cross term. These traces are finite. Every positive-eigenvalue orbital of \gamma belongs to H^1 and is supported in the packet region.

Take a finite eigen-truncation of \gamma. Occupy each retained orbital independently with Bernoulli probability equal to its eigenvalue. Each realization is a normalized Slater determinant, including the possible vacuum. The average one-body energy is the trace energy. Its average repulsion is the direct energy of the truncated density minus

\frac12\sum_{\sigma,\tau}\iint K(x-y)|\gamma(x,\sigma;y,\tau)|^2\,\mathrm dx\,\mathrm dy,

where here \gamma denotes the finite truncation. In particular the average repulsion is at most the direct energy. Equal-orbital direct and exchange contributions cancel, as required by the Bernoulli occupation rule.

Wedge each realization with the normalized core slice. Because their spatial supports are separated, the terms assigning the two groups to different sets of particle labels have disjoint supports. Normalized antisymmetrization consequently preserves the sum of the group energies and adds exactly their direct cross repulsion. Each resulting vector belongs to its own antisymmetric particle-number sector and has energy at least E. Averaging gives the desired inequality with the finite-truncation density and kinetic energy.

For completeness, passage to the full operator needs no selection of infinite Slater states. The truncated densities increase almost everywhere to g_b^2*\rho, and their kinetic energies increase to (3.8). The full density is bounded and compactly supported, so nuclear integrals converge. The core potential is bounded on the packet region by support separation, so its integrals converge as well. Direct energies converge monotonically. Lemma 3.1 gives D(g_b^2*\rho)\leq D(\rho), proving (3.7). The same argument with no inserted orbitals proves E\leq e_X.

The inequality is pointwise for every admissible core slice outside a null set. Later we choose \rho as a measurable function of its conditional field. Only the displayed functional is then averaged; no measurable choice of Slater determinants is necessary.

3.4 A lower comparison with the same kinetic coefficient

An arbitrary out configuration also determines a bounded density, obtained by spreading each retained particle over a small radial kernel. To retain the coefficient \cT in the lower bound, use Neumann eigenvalues in cubes and then average the grid. This is the Neumann-bracketing approach to the semiclassical kinetic coefficient [12, Theorems III.10–III.13]; the retained subset and its radial fine density are specified below.

For b>0, define the radial probability kernel

\vartheta_b(x)=\int_{\mathrm{SO}(3)} b^{-6}\prod_{j=1}^3\big(b-|(Qx)_j|\big)_+\,\mathrm dQ, \tag{3.9}

where Haar measure has mass one. It is bounded by Cb^{-3} and supported in \overline{B(0,\sqrt3b)}.

Lemma 3.6 (Fine density and lower energy bounds). In the setting of Lemma 3.4, let n_o be the out particle count. Choose, measurably, any subset of the out particles and set

\sigma(x)=\sum_{i\ \mathrm{retained}}\vartheta_b(x-x_i).

Then

\begin{align*} T_o&\geq\E\left[\cT\int\sigma^{5/3} -Cb^{-2}(n_o^{4/3}+n_o)\right], \tag{3.10}\\ \sum_{i<j\ \mathrm{out}}K(x_i-x_j) &\geq D(\sigma)-Cn_o/b \quad\text{almost surely}. \tag{3.11}\end{align*}

Proof. On a cube of side b, the spin-two Neumann eigenvalues are \pi^2|m|^2/(2b^2), for m\in\mathbb N_0^3, each with two spin states. The number of lattice points of radius at most s, with this multiplicity, is bounded by

\frac\pi3(s+\sqrt3)^3:

attach a disjoint unit cube to each octant lattice point and enclose their union in the octant ball of radius s+\sqrt3. Thus the jth ordered radius is at least ((3j/\pi)^{1/3}-\sqrt3)_+. Summing their squared radii and using \sum_{j\leq n}j^{2/3}\geq(3/5)n^{5/3} gives the lower bound

b^{-2}\big(\cT n^{5/3}-C(n^{4/3}+n)\big) \tag{3.12}

for the sum of the first n eigenvalues. The leading coefficient is exactly \cT.

Partition the out coordinates into assignments to the cubes of a grid. Restriction to a cube is admissible for its Neumann form; no zero extension across its boundary is involved. Within each cube the corresponding variables remain antisymmetric. The occupation bound, now in the Neumann basis, gives (3.12) after slicing all auxiliary variables. If n_C denotes the out count in a cube, the leading term is

\cT\int\left(\sum_C\frac{n_C}{b^3}\mathbf1_C(x)\right)^{5/3} \mathrm dx.

The error is at most Cb^{-2}(n_o^{4/3}+n_o), since \sum_Cn_C^{4/3}\leq n_o^{4/3}.

Average the grid over a uniform translation in a fundamental cube and over rotations. At a fixed out configuration, its averaged cell density is \sum_{i\ \mathrm{out}}\vartheta_b(x-x_i). Before rotation, the probability that two points are in the same translated cube gives precisely the triangular product in (3.9). Jensen’s inequality bounds the power integral from below by the power of this averaged density. Dropping any chosen particles can only decrease that density and its nonnegative power. This proves (3.10).

For the pair bound, first discard all pairs not both retained. Smearing each retained point by \vartheta_b decreases every distinct pair interaction by Lemma 3.1, because the difference of two independent radial displacements is radial. Each self energy is bounded by C/b, using the kernel’s support and L^\infty bound. Subtracting these self energies from D(\sigma) proves (3.11).

We now have both sides of the local comparison. The upper trial uses an arbitrary nonnegative density in a hole; the lower bound uses the fine density of the electrons actually removed. Their matching \cT\int\rho^{5/3} terms will identify the same convex Thomas–Fermi functional, while Lemma 3.1 measures the difference of the two densities.

4 Local screening and electron counts

We now compare the quantum state in a ball with an unconstrained Thomas–Fermi minimizer in the same ball. The comparison has two outputs: a uniform second-moment bound for the number of nearby electrons, and a quantitative Coulomb-distance estimate for a finer local density. Both estimates hold for every \delta-state. This stability under a small increase of energy will be essential when we later condition on observations. Throughout this section, \psi is a normalized \delta-state in any finite sector n: q_n[\psi]\le E+\delta, where E=\inf_k E_k. No eigenstate assumption or bound on n is used here. Expectations refer to its position and spin law, together with any localization labels that are specified.

4.1 Two local geometries

Fix A=40. We use either of the following scale geometries; the choice is kept fixed throughout each application of this section. All balls in these definitions are open.

\begin{aligned} &\text{nuclear scale:}\qquad L=10^6,\quad\mathcal Y=\R^3,\\ &\hspace{2em}a_y=\sup\{s>0:\nu(B(y,Ls))\le s^{-3}\};\\[.4ex] &\text{atomic distance scale:}\qquad L=10^5,\quad \nu=Z\delta_0,\\ &\hspace{2em}\mathcal Y=\R^3\setminus\{0\},\qquad a_y=|y|/L. \end{aligned} \tag{4.1}

Put B_y=B(y,a_y) and d_y=\min_m|y-R_m|; in the atomic geometry d_y=|y|. The nuclear scale is used for molecular estimates, including balls containing nuclei. The atomic distance scale gives nucleus-free patches at every positive distance from the origin, also below Z^{-1/3}. These scales are distinct: for a single nucleus the first is \max(Z^{-1/3},|y|/10^6).

Lemma 4.1 (Properties of the nuclear scale). In the nuclear-scale geometry, a:\R^3\to(0,\infty) is L^{-1}-Lipschitz and satisfies

Z^{-1/3}\le a_y<\infty,\quad \nu(B(y,La_y))\le a_y^{-3},\quad \nu(B(y,2La_y))>(2a_y)^{-3},\quad d_y\le La_y. \tag{4.2}

If d_y/L>1, then a_y=d_y/L. For every fixed c<L/2, B(y,ca_y) is covered by a bounded number of balls B_z with a_z\asymp a_y. The covering bound depends only on c and L.

Proof. The set of admissible s in (4.1) is downward closed. It contains Z^{-1/3} and is bounded above, since every sufficiently large ball contains all nuclei. Increasing open balls show that the condition also holds at the supremum. The radius 2a_y is not admissible, proving the third inequality in (4.2).

If s=a_x-|x-y|/L>0, then B(y,Ls)\subset B(x,La_x), and hence \nu(B(y,Ls))\le a_x^{-3}\le s^{-3}. Thus a_y\ge s. Interchanging x and y proves the Lipschitz bound. If d_y>La_y, a slightly larger ball in the defining family would still contain no nucleus, a contradiction. If d_y/L>1, every radius below d_y/L is admissible, whereas every strictly larger radius contains a charge at least one and has s^{-3}<1. This proves the asserted equality. Finally, the Lipschitz bound makes all scales in B(y,ca_y) comparable to a_y; a mesh of spacing a sufficiently small multiple of a_y gives the stated cover.

In the atomic geometry the scale is also L^{-1}-Lipschitz, and B(y,La_y) contains no nucleus. Thus in both geometries

\nu(B(y,La_y))\le a_y^{-3}.

For every fixed c<L/2, the ball B(y,ca_y) stays in the target domain \mathcal Y and has a bounded cover by cells B_z of scales comparable to a_y. In the atomic case this follows from |y|=La_y and the same mesh argument. The proofs below use these common local properties. The lower scale bound a_y\ge Z^{-1/3} is not assumed in the atomic case.

For the present \delta-state define

\begin{gathered} n_y=\#\{i:x_i\in B_y\},\qquad m_{0,y}=\max(a_y^{-3},1),\qquad m_y=m_{0,y}+\sqrt{\delta a_y},\qquad e_y=\frac{m_y^2}{a_y},\\ P=\max\left(1,\sup_{y\in\mathcal Y}\frac{\E n_y^2}{m_y^2}\right). \end{gathered} \tag{4.3}

Initially P is merely finite, since n_y\le n and m_y\ge1. We shall prove that it is bounded by a universal constant. Notice that

m_y\ge1,\qquad a_y m_y\ge1,\qquad a_y m_y^{2/3}\ge1, \qquad e_y\asymp\max(a_y^{-7},a_y^{-1},\delta). \tag{4.4}

These facts hold also when a_y>1. Define the raw far field

J_y=\int_{|v-y|\ge Aa_y}\frac{d\nu(v)}{|y-v|} -\sum_{|x_i-y|\ge Aa_y}\frac1{|y-x_i|}. \tag{4.5}

The exclusion removes its singularities and, for each fixed system, |J_y|\le (Z+n)/(Aa_y). In the atomic geometry the nuclear term is exactly V(y)=Z/|y|, since A<L.

4.2 A positive-field estimate

A deterministic cut and its recorded out data X have the meaning of Lemma 3.4. The next estimate permits a finite initial sequence of cuts; the proof appends further deterministic cuts only to rule out a large positive field.

Lemma 4.2 (Conditional positive fields). Fix C_0\ge1. Suppose the initial sequence is absent, or its total out support is covered by at most C_0 balls B_z and the sum of its cuts’ squared gradients is bounded by

\sum_z D_z^2a_z^{-2}\1_{B_z}, \qquad \frac{D_z^2}{a_zm_z}\le C_0\sqrt P.

If X denotes its data (trivial for an absent sequence), and e_* is the maximum of e_y and the energies e_z of these covering cells, then

\big\|(\E[J_y\mid X])_+\big\|_2 \le C(C_0)\sqrt{\frac{P e_*}{a_y}}. \tag{4.6}

Proof. We first give the upper trial at a target y. Append a cut that is full out on B(y,Aa_y), supported in B(y,2Aa_y), and has gradients bounded by C/a_y. Write X' for the enlarged data, a=a_y, and h=\E[J_y\mid X']. The sliced core vanishes on B(y,Aa). Take uniform packet centers of total mass M_{\rm tr}\ge0 in B(y,a), with packet width a. The packet support lies in B(y,2a) and is separated from the core. The radial mean of the core field and of each far nuclear field is its value at y. Near nuclei contribute positively, and J_y subtracts far out electrons as well as the core. Therefore Lemma 3.5 gives

E\le e_{X'}-M_{\rm tr}h+C\left(\frac{M_{\rm tr}^{5/3}}{a^2} +\frac{M_{\rm tr}}{a^2}+\frac{M_{\rm tr}^2}{a}\right). \tag{4.7}

Here M_{\rm tr} is the expected occupation of the packet trial; it need not be an integer. This use of an arbitrary trial mass is justified by E=\inf_k E_k.

For ah>C_1m_{0,y} choose M_{\rm tr}=\lambda ah. The three positive terms in (4.7), divided by M_{\rm tr}h, are at most

\frac{C\lambda^{2/3}}{a(ah)^{1/3}},\qquad \frac{C}{a(ah)},\qquad C\lambda.

The inequalities am_{0,y}^{1/3}\ge1 and am_{0,y}\ge1 allow us to choose \lambda>0 small and then C_1 large so that their sum is less than a fixed number below one. In the other case use the vacuum trial. For all data this proves

E\le e_{X'}-ca h_+^2+C\frac{m_{0,y}^2}{a}. \tag{4.8}

The insertion estimate makes a large positive field expensive. We bound the energy of the removed electrons in terms of positive fields at nearby centers. If the present field exceeded a universal multiple of its proposed bound, this comparison would force a larger normalized field after one further deterministic cut. Repetition gives doubly exponential growth, whereas the elementary nuclear bound and the Lipschitz scale permit only exponential growth. We now quantify this argument, retaining the original e_* throughout.

Start with target v_0=y and the given data X_0=X. At stage j, append the cut just constructed at the current deterministic target v_j; denote the enlarged data by X_{j+1}. The upper estimate (4.8) applies with y=v_j and X'=X_{j+1}. Cover the supports of all cuts, including this new cut, by at most C(j+1) local cells, and let \mathcal U_j be the union of their doubled balls 2B_z. These are the possible next targets: we estimate the removed energy using their fields under the enlarged data, writing X'=X_{j+1} in this calculation. Each newly added scale is comparable to a preceding covering scale by the common local scale properties above; the original target and initial covering scales need not be comparable to one another. Let a_{\min}>0 be the minimum scale of the original target and initial covering cells. The Lipschitz property and the bounded local meshes give, for every later target or covering cell at iteration j,

a_v\ge C^{-(j+1)}a_{\min},\qquad e_v\le C^{j+1}e_*. \tag{4.9}

Indeed each new scale is comparable to a preceding scale; the quantities m(a)=\max(a^{-3},1)+\sqrt{\delta a} and e(a)=m(a)^2/a change by a bounded factor when a does, uniformly in \delta. The total out count obeys

\|n_o\|_2\le\sum_{\text{covering cells }z}\|n_z\|_2 \le\sqrt P\sum_zm_z. \tag{4.10}

The localization error is at most C^{j+1}Pe_*: for an initial cell this follows from

D_z^2a_z^{-2}\E n_z \le\sqrt P\,\frac{D_z^2}{a_zm_z}e_z\le C_0Pe_z,

and for a later cell it follows from a_zm_z\ge1 and \E n_z\le\sqrt Pm_z.

For a covering cell B_z, let V_z be the potential of nuclei in B(z,4a_z). Let h_z(v) be the conditional raw signed field, given the present X', of all sources at distance at least 4a_z from z. It has a jointly measurable harmonic version on 3B_z: all sources are separated from compact subballs, so their kernel derivatives are bounded for the fixed system and may be integrated against the conditional law. On B_z the field of the conditional core satisfies

\Phi_{X'}\le V_z+h_z+\text{the far out-electron potential}. \tag{4.11}

For v\in2B_z, the exclusion in J_v contains B(z,4a_z), since A=40 and nearby scales are comparable. Extra electrons in h_z can only lower the field. Extra nuclei have total charge at most a_z^{-3} and distance at least 2a_z from v. Hence

h_z(v)\le\E[J_v\mid X']+Ca_z^{-4}. \tag{4.12}

Set

G(v,X')=\sqrt{\frac{a_v}{e_*}} \big\|(\E[J_v\mid X'])_+\big\|_2.

Positive parts of harmonic functions are subharmonic. Their ball submean inequality, a fixed covering of B_z, and Minkowski’s inequality give

\begin{align*} \left\|\sup_{B_z}(h_z)_+\right\|_2 &\le Ca_z^{-3}\int_{2B_z}\|(h_z(v))_+\|_2\,dv\tag{4.13}\\ &\le C^{j+1}\sqrt{\frac{e_*}{a_z}} \left(1+\sup_vG(v,X')\right),\end{align*}

where the supremum is over v\in\mathcal U_j. The term a_z^{-4} was absorbed using a_z^{-7}\le e_z\le C^{j+1}e_*.

The out addback in (4.11) is at most

C\sum_l\frac{n_l}{\max(a_l,a_z)}.

Indeed the far exclusion gives distance at least 3a_z; if a_l\gg a_z, Lipschitzness of the scale forces every point of B_l to be a distance at least a fixed multiple of a_l from B_z. Using \|n_l\|_2\le\sqrt{Pe_la_l} and \sqrt{a_l}/\max(a_l,a_z)\le a_z^{-1/2} bounds this addback in L^2 by C^{j+1}\sqrt{Pe_*/a_z}.

For completeness, the nuclear singularities have the required energy scale. If Q_z=\nu(B(z,4a_z))\le a_z^{-3}, weighted convexity gives

\int_{B_z}V_z^{5/2} \le Q_z^{3/2}\sum_m z_m \int_{B_z}|v-R_m|^{-5/2}\,dv \le C Q_z^{5/2}a_z^{1/2}\le Ca_z^{-7}. \tag{4.14}

In the sum over cells, the power of the number of cells arising from convexity is bounded by C^{j+1}. Lemma 3.2 and Young’s inequality therefore absorb this attraction at cost C^{j+1}e_*. Multiplying the other bounds by \|n_z\|_2\le\sqrt{Pe_za_z} and summing cells, the conditional localization identity, with out-pair repulsion dropped, yields

q_n[\psi]+\mathrm{IMS} \ge\E e_{X'}-C^{j+1}e_* \left(P+\sqrt P\sup_vG(v,X')\right). \tag{4.15}

This calculation used the actual list of cuts; it did not assume the conclusion of the lemma for that list.

Combine (4.8) and (4.15), use \delta\le e_*, and apply conditional Jensen from the enlarged data back to the preceding data. With G(v_j,X_j) defined by the same normalization,

G(v_j,X_j)^2\le C^{j+1} \left(P+\sqrt P\sup_{v\in\mathcal U_j}G(v,X_{j+1})\right). \tag{4.16}

Write g_j=G(v_j,X_j)/\sqrt P. Whenever g_j^2\ge2C^{j+1}, the last inequality permits a deterministic next target v_{j+1}\in\mathcal U_j with

g_{j+1}\ge\frac{g_j^2}{4C^{j+1}},\qquad \log g_{j+1}\ge2\log g_j-(j+1)\log C-\log4.

The series

S=\sum_{j\ge0}2^{-j-1}\big((j+1)\log C+\log4\big)

converges. Choose M_0>0 so that \exp(2^{j+1}M_0)\ge2C^{j+1} for every j. If \log g_0>S+M_0, induction gives \log g_j\ge2^jM_0; thus the condition for selecting each next target always holds. All supremums here are of numerical norms for deterministic cuts; choosing a target close to one of them never chooses a target from sampled data. On the other hand, J_v\le Z/(Aa_v) pointwise, and (4.9) gives

G(v,X')\le\sqrt{\frac{a_v}{e_*}}\frac{Z}{Aa_v} \le C^{j+1}\frac{Z}{A\sqrt{e_*a_{\min}}}.

For the fixed system and initial cuts the last factor is finite. Its logarithm grows at most linearly in j, contradicting the positive multiple of 2^j forced above. This argument works in both geometries and requires no global lower bound on the scale. It proves (4.6).

4.3 Comparison in a ball

We now use the positive-field estimate to control the full local quantum energy. Besides bounding counts, the comparison retains its Coulomb error and the cost of placing electrons where the comparison field is negative. We use the constants

p=\frac32,\qquad k=\left(\frac53\cT\right)^{-3/2},\qquad \cF=4\pi k.

Lemma 4.3 (Conditional comparison in an interior ball). Fix y\in\mathcal Y, write a=a_y, m=m_y, e=e_y, and choose 0<\beta<1/100 such that

\frac{\beta^{-2}}{am}\le\sqrt P. \tag{4.17}

Set b=\beta a. There is a deterministic t_0\in[5a,6a] and a cut full out on B(y,t_0), supported in B(y,t_0+b), with gradients at most C/b. Let X be its out data, \rho_X^c the conditional core density, \Phi_X=V-K*\rho_X^c, and \Omega=B(y,t_0-4b). There is a unique minimizer \rho=\rho_X\ge0, extended by zero outside \Omega, of

\mathcal T_X(\rho)=\cT\int\rho^{5/3}-\int\Phi_X\rho+D(\rho). \tag{4.18}

It is measurable in X and, with W=\Phi_X-K*\rho, satisfies

\rho=kW_+^{3/2}\quad\hbox{in }\Omega. \tag{4.19}

Retain the out particles with |x_i-y|<t_0-7b and put \sigma=\sum_{i\ \mathrm{retained}}\vartheta_b(\cdot-x_i), using the radial fine kernel from Lemma 3.6. Write

\mathcal L=\cT\int\left(\sigma^{5/3}-\rho^{5/3} -\frac53\rho^{2/3}(\sigma-\rho)\right). \tag{4.20}

For every sufficiently small \epsilon>0,

\begin{align*} &\E\left[D(\sigma-\rho)+\mathcal L+\int W_-\sigma\right]\tag{4.21}\\ &\quad\le C\left[\delta+(\epsilon+\sqrt\beta)Pe +\epsilon^{-3/2}\beta^{1/2}a^{-7} +b^{-1}\sqrt Pm +b^{-2}\left(P^{2/3}m^{4/3}+\sqrt Pm\right)\right].\end{align*}

Moreover, \E\int\sigma^{5/3} is bounded by CPe plus a constant times this right-hand side, and the out kinetic energy obeys

T_o\le C\left(Pe+b^{-2}\sqrt Pm\right). \tag{4.22}

Finally, independently of the data,

W\le V_{\rm loc}+Ca^{-4}\quad\hbox{on }B(y,3a),\qquad \int_{B(y,2a)}\rho\le Ca^{-3}, \tag{4.23}

where V_{\rm loc} is the potential of nuclei in B(y,20a). If this local nuclear measure is zero, as it always is in the atomic distance geometry, the same construction has the sharper bound

\E\left[D(\sigma-\rho)+\mathcal L+\int W_-\sigma\right] \le C\left[\delta+\sqrt\beta Pe+b^{-1}\sqrt Pm +b^{-2}\left(P^{2/3}m^{4/3}+\sqrt Pm\right)\right], \tag{4.24}

and its interior bounds include

W\le Ca^{-4},\qquad \rho\le Ca^{-6} \quad\hbox{on }B(y,3a),\qquad \int_{B(y,2a)}\rho\le Ca^{-3}. \tag{4.25}

The Coulomb error D(\sigma-\rho) controls smooth tests of \sigma-\rho in mean, leaving exceptional cut data possible. The penalty \int W_-\sigma integrates the negative field against the fine density of retained electrons. Together with the later oscillation estimates and a lower bound on this density’s local mass, it provides the additional control needed to pass a lower field estimate to expectation.

Proof. We divide the proof into the choice of cut, the two energy comparisons, and the deterministic interior bound.

Figure 1: Radial supports in the interior comparison (schematic, not to scale). Fine smears of retained particles lie inside the TF domain, and the upper packets remain at distance at least 3b from the conditional core. This particle-support geometry is common to both applications. The atomic distance scale makes B(y,20a) free of nuclei; the molecular scale may leave nuclei there, and their packet loss is retained in (4.21).

Choice of cut and the conditional field. For a candidate t\in[5a,6a], let the cut transition in a shell of width b, using sine and cosine of an angle. Let n_{\rm del} count the out particles not retained. Such a particle lies in t-7b\le|x-y|\le t+b. For each raw pair of particles the set of t for which both lie in this shell has length at most 8b. Averaging over t therefore bounds its expected squared count by C\beta Pm^2, since B(y,7a) has a bounded comparable-scale cover. The same averaging, applied to the nuclear integral, uses (4.14) to give a bound C\beta a^{-7}. Averaging the sum of the two normalized nonnegative quantities selects one t_0 for which both bounds hold:

\begin{gathered} \E n_{\rm del}^2\le C\beta Pm^2,\qquad \E n_o^2\le CPm^2,\qquad \mathrm{IMS}\le Cb^{-2}\sqrt Pm,\\ \int_{\{t_0-7b\le|x-y|\le t_0+b\}}V_{\rm loc}^{5/2} \le C\beta a^{-7}. \end{gathered} \tag{4.26}

The full out-count and IMS bounds in the same display follow from the comparable-scale cover and \E n_z\le\sqrt Pm_z.

On the cut support and on \Omega we have

\Phi_X\le V_{\rm loc}+F,\qquad F\ge0,\qquad \|F\|_2\le C\frac{\sqrt Pm}{a}. \tag{4.27}

To see this, the raw sources outside B(y,20a) give a harmonic conditional field on B(y,10a); these electrons are all core particles. Its value at v\in B(y,10a) is at most \E[J_v\mid X]+Ca^{-4}, by the same exclusion comparison as (4.12). Take F to be the positive supremum on B(y,7a). Harmonic means and Lemma 4.2 prove (4.27). The cells of this initial cut have scale comparable to a and D_z\le C\beta^{-1}, so (4.17) verifies that lemma’s hypothesis.

The unconstrained minimizer. The core is at distance at least 4b from \Omega, so its potential is bounded and smooth there. Hence \Phi_X\in L^{5/2}(\Omega). Young’s inequality makes (4.18) coercive in L^{5/3}. The positive Coulomb form is weakly lower semicontinuous: by Lemma 3.1 it is a squared Hilbert norm, or one may express it as the supremum of its affine dual forms. The direct method on the closed positive cone gives a minimizer, and strict convexity of the kinetic term gives uniqueness. Nonnegative variations, followed by signed compact multiplicative variations, give

\frac53\cT\rho^{2/3}-\Phi_X+K*\rho\ge0, \qquad \left(\frac53\cT\rho^{2/3}-\Phi_X+K*\rho\right)\rho=0,

which is (4.19).

This minimizer depends continuously in L^{5/3} on its field in L^{5/2}. Indeed convergent fields give uniformly bounded minimizers; weak lower semicontinuity and comparison with the limit minimizer identify each weak limit and give convergence of the minimum values. Lower semicontinuity of D then forces convergence of the kinetic norms. Uniform convexity of L^{5/3} gives strong convergence. The conditional field, being jointly measurable and taking values in the separable space L^{5/2}(\Omega), is measurable as a function with values in that space. The continuity just proved establishes the stated measurability of \rho.

The diameter of \Omega is at most 12a, so D(\rho)\ge(\int\rho)^2/(24a). The minimum is nonpositive because zero is admissible. Absorbing V_{\rm loc} with Young’s inequality in (4.27) gives

\frac{(\int\rho)^2}{Ca}\le Ca^{-7}+F\int\rho.

It follows that

\int\rho\le C(aF+a^{-3}),\qquad \int\rho^{5/3}\le C(aF^2+a^{-7}). \tag{4.28}

When V_{\rm loc}=0, the same nonpositive-minimum argument uses only \Phi_X\le F and gives the sharper estimates

\int\rho\le CaF,\qquad \int\rho^{5/3}\le CaF^2. \tag{4.29}

In particular all trial errors below are integrable in X.

Upper quantum comparison. The centers \rho lie in \Omega=B(y,t_0-4b); packets of width b remain at distance at least 3b from the core. Thus Lemma 3.5 applies, and radial smearing leaves the core potential unchanged. The nuclear loss is bounded at centers by

V_b^{\rm loss}(x)=\sum_{R_m\in B(y,20a)} \frac{z_m}{|x-R_m|}\1_{\{|x-R_m|\le2b\}}.

Weighted convexity, the total local charge bound, and integration of |x|^{-5/2} over a ball of radius 2b give

\int(V_b^{\rm loss})^{5/2}\le C\beta^{1/2}a^{-7}.

Nuclei not in the indicated local ball are harmonic on all packets. Young’s inequality now gives, pathwise,

E\le e_X+\mathcal T_X(\rho)+Cb^{-2}\int\rho +C\epsilon\int\rho^{5/3} +C\epsilon^{-3/2}\beta^{1/2}a^{-7}. \tag{4.30}

Lower quantum comparison. Reserve a fraction \epsilon T_o of the out kinetic energy. The coarse kinetic inequality absorbs both V_b^{\rm loss} and the nuclear attraction of deleted particles, at cost C\epsilon^{-3/2}\beta^{1/2}a^{-7}, using (4.26). The deleted F contribution costs at most

\|F\|_2\|n_{\rm del}\|_2\le C\sqrt\beta Pe.

The retained fine density \sigma is supported in \Omega, because its centers have radius less than t_0-7b and its kernel radius is \sqrt3b. The core potential is harmonic on these kernels, and the loss of nuclear attraction is again covered by V_b^{\rm loss} at the actual particle positions. Applying the remaining fraction of Lemma 3.6 and its pair-repulsion bound in the localization identity gives

\begin{align*} q_n[\psi]+\mathrm{IMS} &\ge\E\left[e_X+\mathcal T_X(\sigma) -\epsilon\cT\int\sigma^{5/3}\right] -C\mathcal R,\tag{4.31}\\ \mathcal R&=\epsilon^{-3/2}\beta^{1/2}a^{-7} +\sqrt\beta Pe+b^{-1}\sqrt Pm +b^{-2}\left(P^{2/3}m^{4/3}+\sqrt Pm\right).\end{align*}

Here \E n_o^{4/3}\le(\E n_o^2)^{2/3}; no higher out-count moment is required.

The Euler equation gives the exact expansion

\mathcal T_X(\sigma)-\mathcal T_X(\rho) =D(\sigma-\rho)+\mathcal L+\int W_-\sigma. \tag{4.32}

Besides being nonnegative, the convex remainder satisfies

\mathcal L\ge c\int\sigma^{5/3}-C\int\rho^{5/3},

by Young’s inequality applied to the tangent term. For small \epsilon this absorbs \epsilon\cT\int\sigma^{5/3} into half of \mathcal L, with error C\epsilon\int\rho^{5/3}. Average (4.30), compare it with (4.31), and use (4.28), (4.27), and the IMS bound. The terms \epsilon\E\int\rho^{5/3} cost C\epsilon Pe; the packet kinetic term costs Cb^{-2}(\sqrt Pm+a^{-3})\le Cb^{-2}\sqrt Pm. This proves (4.21), after multiplying its constant to restore the full nonnegative remainder, and also the asserted bound for \E\int\sigma^{5/3}.

The source-free improvement. If \nu(B(y,20a))=0, every nucleus and the conditional core are outside the packet supports. The field \Phi_X is harmonic on those supports, so radial averaging is exact and the upper comparison is

E\le e_X+\mathcal T_X(\rho)+Cb^{-2}\int\rho. \tag{4.33}

For the lower comparison, use all the out kinetic energy. Harmonicity and the deleted-count bound give

\sum_{i\ \mathrm{retained}}\Phi_X(x_i)=\int\Phi_X\sigma, \qquad \E(Fn_{\rm del})\le C\sqrt\beta Pe.

The full sharp kinetic and pair bounds of Lemma 3.6 therefore give

q_n[\psi]+\mathrm{IMS} \ge\E[e_X+\mathcal T_X(\sigma)] -C\left[\sqrt\beta Pe+b^{-1}\sqrt Pm +b^{-2}(P^{2/3}m^{4/3}+\sqrt Pm)\right]. \tag{4.34}

Subtract the average upper inequality and use the exact expansion (4.32), the mass estimate (4.29), and the IMS bound. This proves (4.24), including its full convex remainder, without the nuclear loss or an \epsilon error.

There is a useful separate kinetic bound. In the localization identity use only e_X\ge E, drop pair repulsion, and use (4.27). Half the coarse kinetic inequality absorbs V_{\rm loc} at cost Ca^{-7}; also \E(Fn_o)\le CPe. The result is (4.22).

Interior field bound. The core vanishes in B(y,4a) and this ball lies in \Omega. There

\Delta W=-4\pi\nu+\cF W_+^{3/2}.

Put s=4a and

U(x)=V_{\rm loc}(x)+\frac{C s^4}{(s^2-|x-y|^2)^4}.

The Laplacian of the bump is at most 80Cs^6/(s^2-|x-y|^2)^6. For a sufficiently large universal C this is at most \cF times its 3/2 power. Thus U is a supersolution for the displayed equation. The difference W-V_{\rm loc} is bounded above: the far nuclear field is bounded on this ball, the core potential is nonnegative, and K*\rho\ge0. Consequently (W-U)_+ has compact support inside the ball. Nuclear singularities cancel in W-U, which is locally H^1; testing the difference inequality by its positive part yields

-\int|\nabla(W-U)_+|^2 \ge\cF\int_{\{W>U\}}(W_+^{3/2}-U^{3/2})(W-U)\ge0.

The test is valid by compact H^1 approximation: the densities are locally in L^{5/3}, and the nuclear point terms have already canceled. Hence W\le U. On B(y,3a) the bump is Ca^{-4}, proving the first part of (4.23). If V_{\rm loc}=0, this yields W\le Ca^{-4}; the Euler equation then gives \rho\le Ca^{-6} and proves (4.25). In this source-free case,

\Delta W=\cF W_+^{3/2}=4\pi\rho \quad\hbox{on }B(y,4a). \tag{4.35}

Finally, weighted powers and \nu(B(y,20a))\le a^{-3} give

\int_{B(y,2a)}\rho \le C\int_{B(y,2a)}(V_{\rm loc}^{3/2}+a^{-6}) \le C(a^{-9/2}a^{3/2}+a^{-3})\le Ca^{-3}.

4.4 Closing the count estimate

The comparison in a hole bounds its electron count through a smooth Coulomb test. The resulting inequality improves any sufficiently large value of the provisional constant P, and therefore makes that constant universal.

Lemma 4.4 (Local second moments). For every normalized \delta-state in any finite sector and every y\in\mathcal Y,

\E n_y^2\le C\left(\max(a_y^{-6},1)+\delta a_y\right). \tag{4.36}

In particular the number P in (4.3) is at most a universal constant.

Proof. Fix small \epsilon>0 and 0<\beta<1/100, to be chosen in that order. We need only consider P\ge\beta^{-4}, since \beta will be fixed universally. Then \beta^{-2}/(am)\le\sqrt P at every target, and the patch of Lemma 4.3 is available. Every raw particle in B_y is retained, and its fine smear is contained in B(y,1.1a) because \beta<1/100. Choose a nonnegative smooth \chi, equal to one there, supported in B(y,2a), with \|\nabla\chi\|_2\le C\sqrt a. Lemma 3.1 and (4.23) give

n_y\le\int\chi\sigma \le Ca^{-3}+C\sqrt{aD(\sigma-\rho)},\qquad \E n_y^2\le Ca^{-6}+Ca\,\E D(\sigma-\rho).

Divide by Pm^2 and use (4.21). Since \delta a\le m^2, the result is at most

\begin{align*} C\bigg[&P^{-1}+\epsilon+\sqrt\beta +\frac{\epsilon^{-3/2}\beta^{1/2}}P +\frac{\beta^{-1}}{\sqrt Pm}\tag{4.37}\\ &+\frac{\beta^{-2}}{P^{1/3}am^{2/3}} +\frac{\beta^{-2}}{\sqrt Pam}\bigg].\end{align*}

In the atomic distance geometry, using (4.24) instead gives the sharper intermediate inequality

\frac{\E n_y^2}{Pm_y^2} \le C\left[P^{-1}+\sqrt\beta +\frac{\beta^{-1}}{\sqrt Pm_y} +\frac{\beta^{-2}}{P^{1/3}a_ym_y^{2/3}} +\frac{\beta^{-2}}{\sqrt P a_ym_y}\right]. \tag{4.38}

For the common bound it suffices to use (4.37) in both geometries. First choose \epsilon small, then \beta small, and finally a universal threshold P_0 large. The inequalities (4.4) show that the expression is at most 1/2 whenever P>P_0. Enlarge P_0 so that P_0\ge\beta^{-4}; this verifies (4.17) at every target. If P>P_0, we would obtain \E n_y^2/m_y^2\le P/2 for every y, contradicting the definition of P. Thus P\le P_0. Since m_y^2\le2\max(a_y^{-6},1)+2\delta a_y, this proves (4.36).

Proposition 4.5 (Uniform local counts and conditional fields). In either geometry, every normalized \delta-state in a finite sector satisfies P\le C. Fix y\in\mathcal Y. Suppose the initial finite sequence of cuts has total out support covered by at most C_0 cells B_z, with C_0^{-1}\le a_z/a_y\le C_0, and satisfies the gradient hypothesis of Lemma 4.2. The absent-cut case is allowed. Then

P\le C,\qquad \big\|(\E[J_y\mid X])_+\big\|_2 \le C(C_0)\frac{m_y}{a_y}. \tag{4.39}

Neither constant depends on the nuclear system, particle number, state, target, or \delta.

Proof. The count assertion is Lemma 4.4. Comparable scales have comparable m and e=m^2/a, uniformly in \delta, so e_*\le C(C_0)e_y in Lemma 4.2. Substitute P\le C into that lemma to obtain the field assertion.

Lemma 4.6 (Fine comparison and local density). There is a universal a_0>0 with the following property. If a=a_y<a_0 and \psi is a \delta-state with \delta\le a^{-7+0.02}, choose the patch of Lemma 4.3 with b=a^{1+0.2}. Its densities obey

\E\left[D(\sigma-\rho)+\mathcal L+\int W_-\sigma\right] \le Ca^{-7+0.02},\qquad \E\int\sigma^{5/3}\le Ca^{-7}. \tag{4.40}

The raw one-body density satisfies

\int_{B(y,4a)}\rho_\psi^{5/3}\le Ca^{-7}. \tag{4.41}

In particular, the two estimates needed in the atomic application are

\E\left[D(\sigma-\rho)+\int W_-\sigma\right]\le Ca^{-7+.02}, \qquad \int_{B(y,4a)}\rho_\psi^{5/3}\le Ca^{-7}. \tag{4.42}

Proof. Take \beta=a^{0.2} and \epsilon=a^{0.02}. The energy assumption gives m\le Ca^{-3}, while \beta^{-2}/(am)\le a^{1.6}, so the patch hypothesis holds for small a. By Lemma 4.4, P\le C. The terms on the right of (4.21) are bounded respectively by constant multiples of

a^{-6.98},\quad a^{-6.98}+a^{-6.9},\quad a^{-6.93},\quad a^{-4.2},\quad a^{-6.4}+a^{-5.4}.

All are at most Ca^{-7+0.02} for a<1, proving (4.40). Equation (4.22) gives T_o\le Ca^{-7}. Since the cut is full out on B(y,4a), the out density equals \rho_\psi there. Applying Lemma 3.2 proves (4.41).

Corollary 4.7 (Raw near-Coulomb bound). Under the hypotheses of Lemma 4.6, for 0<u\le4a,

\E\sum_{|x_i-y|<u}\frac1{|x_i-y|} \le Ca^{-4}(u/a)^{1/5}. \tag{4.43}

Proof. The expectation is \int_{B(y,u)}|x-y|^{-1}\rho_\psi(x)\,dx. Hölder’s inequality, the raw density bound, and direct radial integration give

\int_{B(y,u)}\frac{\rho_\psi(x)}{|x-y|}\,dx \le\left(\int_{B(y,4a)}\rho_\psi^{5/3}\right)^{3/5} \left(\int_{|z|<u}|z|^{-5/2}\,dz\right)^{2/5} \le Ca^{-21/5}u^{1/5}.

This is the stated bound in either geometry.

4.5 Source-free oscillation and atomic annuli

The next estimate controls also a very negative field. It applies when the patch contains no local nuclear source; molecular patches containing nuclei instead use the offset oscillation estimate proved with the nuclear splitting below.

Lemma 4.8 (Interior oscillation). For every patch in Lemma 4.3 with \nu(B(y,20a))=0, and every 0<s'\le a/2, almost surely in its data,

\sup_{x\in B(y,s')}|W(x)-W(y)| \le C\frac{s'}a\bigl(a^{-4}+W(y)_-\bigr). \tag{4.44}

Proof. By (4.35) and (4.25), 0\le\Delta W\le Ca^{-6} on B(y,2a). Write

Q(x)=\frac1{4\pi} \int_{B(y,2a)}\frac{\Delta W(z)}{|x-z|}\,\dd z.

For x\in B(y,2a), direct integration of |x-z|^{-1} and |x-z|^{-2} gives

0\le Q(x)\le Ca^{-4},\qquad |\nabla Q(x)|\le Ca^{-5}.

Since \Delta Q=-\Delta W inside that ball, H=W+Q is harmonic there. By (4.25), H\le C_1a^{-4}. Choose C_2>C_1 universally and put h=C_2a^{-4}-H, a positive harmonic function on B(y,2a). The Poisson formula on a sphere of radius 3a/2 gives

\sup_{B(y,a)}|\nabla h|\le Ca^{-1}h(y).

Indeed the differentiated Poisson kernel on B(y,a) is bounded by C/a times its value at the center; integrating the nonnegative boundary values gives precisely this inequality. Also h(y)\le Ca^{-4}+W(y)_-, since Q(y)\ge0. Integrate the gradient along segments in B(y,s'), and add the bound for \nabla Q. This proves (4.44).

Corollary 4.9 (Annular counts). In the atomic distance geometry, for every 0<\lambda<\Lambda<\infty and u>0, every normalized \delta-state of finite particle number satisfies

\left\|\#\{i:\lambda u<|x_i|<\Lambda u\}\right\|_2 \le C_{\lambda,\Lambda} \bigl(\max(u^{-3},1)+\sqrt{\delta u}\bigr). \tag{4.45}

All constants are independent of Z and of the particle number.

Proof. The compact annulus \{\lambda\le|x|\le\Lambda\} has a finite cover by cells B_z whose radii are comparable to one, with constants allowed to depend on \lambda,\Lambda,L. Dilate this cover by u. Because a_{uz}=ua_z, the dilated balls are again cells, now with radii comparable to u. The annular count is bounded by their sum of counts. Minkowski’s inequality and (4.39) bound its L^2 norm by C\sum_z m_z, which is the right side of (4.45). Boundary spheres carry zero raw probability, since the one-electron density is absolutely continuous. Thus the same estimate holds with any choice of open or closed endpoints.

5 Common observation and change-of-law estimates

The two geometries use different master widths and nuclear fields, but share the observation likelihood, the cost of imposing an event, and the transfer from the observed field to a fresh patch field. We prove these statements here. In particular, the last transfer compares expectations under a specified law; it does not identify the two conditional fields on individual configurations.

5.1 Likelihoods and conditional versions

Let \Psi be a normalized antisymmetric state in a finite n-electron sector. Under a probability law P, raw positions and spins (x,\boldsymbol\sigma) have density |\Psi|^2. Fix finitely many widths \ell_0,\ldots,\ell_{m-1}>0. Independently of the raw data, take independent scalar noises U_{ji,b} with density

\zeta(u)=c_\zeta\exp\!\left(-\frac1{1-u^2}\right) \1_{(-1,1)}(u).

At scale j, form the labeled observations \widehat Y_{ji,b}=x_{i,b}+\ell_jU_{ji,b} and then forget the particle labels separately in each array. Represent the result by its lexicographically sorted tuple Y_j in the strict sorted chamber \mathcal C\subset(\R^3)^n. Ties have probability zero. Set

\mathcal F_j=\sigma(Y_j,\ldots,Y_{m-1}),\qquad \mathcal F_m=\{\varnothing,\Omega\}.

Thus the sigma-fields decrease as j increases.

Let t_z be a deterministic measurable width with t_z\ge t_{\min}>0 for the fixed system, and use the smooth radial packet of Section 3 to define \mathcal K_z(y)=g_{t_z}(y-z)^2. Write V=V_s+V_c, where V_s is the deterministic nuclear potential retained in the observed field. In the molecular application it is the smoothed nuclear potential. In the atomic application V_s=V and V_c=0. Where relevant put \nu_s=-(4\pi)^{-1}\Delta V_s distributionally; it is the smoothed nuclear measure in the first case and the original point measure in the second.

Lemma 5.1 (Conditional densities and fields). There are jointly Borel versions of

\mu_j(y)=\E_P\!\left[\sum_{i=1}^n\mathcal K_{x_i}(y) \mid\mathcal F_j\right], \qquad H_j(y)=V_s(y)-(K*\mu_j)(y),

with the following properties. At every positive-density data tuple, \mu_j\ge0, \int\mu_j=n, and \mu_j is smooth in its spatial variable. Every spatial derivative has a deterministic bound for the fixed system. The potential K*\mu_j is C^1, with bounded value and gradient, and

\Delta H_j=-4\pi\nu_s+4\pi\mu_j \tag{5.1}

in distributions. In particular, the always valid regularity statement is that H_j-V_s is C^1 and bounded with bounded gradient. If V_s and its gradient are bounded and continuous, these conclusions hold for H_j itself. Conditional averaging satisfies

\E_P[\mu_j(y)\mid\mathcal F_{j+1}]=\mu_{j+1}(y),\qquad \E_P[H_j(y)\mid\mathcal F_{j+1}]=H_{j+1}(y) \tag{5.2}

where V_s(y) is finite. The same towers hold for nonnegative spatial integrals, and for integrable signed observables. These statements include the trivial data at j=m. None of the fixed-system regularity bounds is asserted to be uniform in the nuclear system or in t_{\min}.

Proof. On \mathcal C the exact likelihood of an array is

L_j(x,Y_j)=\sum_{\pi\in S_n}\prod_{i=1}^n\prod_{b=1}^3 \ell_j^{-1}\zeta\!\left( \frac{Y_{j,\pi(i),b}-x_{i,b}}{\ell_j}\right). \tag{5.3}

Set it equal to zero outside the chamber. Integration of the permutation sum over \mathcal C equals integration of the labeled product over all arrays, and is therefore one. Define

\Lambda_{\ge j}(x,Y)=\prod_{h=j}^{m-1}L_h(x,Y_h),\qquad p_{\ge j}(Y)=\sum_{\boldsymbol\sigma}\int |\Psi(x,\boldsymbol\sigma)|^2\Lambda_{\ge j}(x,Y)\dd x,

with the empty product and p_{\ge m} both equal to one. At a tuple with p_{\ge j}>0, use the probability density |\Psi|^2\Lambda_{\ge j}/p_{\ge j} as the conditional raw law. Equivalently, the conditional mean of a nonnegative Borel raw observable G is the ratio

\frac{\displaystyle\sum_{\boldsymbol\sigma}\int G(x,\boldsymbol\sigma)|\Psi(x,\boldsymbol\sigma)|^2 \Lambda_{\ge j}(x,Y)\dd x} {p_{\ge j}(Y)}.

On zero-density tuples use the unconditional raw law. All these versions are jointly Borel, including their dependence on an additional spatial variable. At every parent tuple with p_{\ge j+1}>0, the conditional density of the next array is p_{\ge j}/p_{\ge j+1}. Tonelli’s theorem and \int L_j\dd Y_j=1 show that it integrates to one. Substitution of the ratios gives the tower property, also after nonnegative spatial integration; positive and negative parts give the integrable signed case.

For each multi-index \alpha, |\partial_y^\alpha\mathcal K_z(y)| \le C_\alpha t_{\min}^{-3-|\alpha|} uniformly in z,y. Differentiation under the conditional integral therefore gives all claimed derivatives and bounds. Tonelli gives the mass n. For the potential and its gradient, split the kernels |u|^{-1} and |u|^{-2} at unit distance. The near parts are integrable and are controlled by \|\mu_j\|_\infty; the far parts are controlled by n. Splitting again at a small radius, then using dominated convergence on its complement, proves continuity of the potential and gradient. Finally -\Delta K=4\pi\delta_0 gives (5.1). In the atomic case this argument does not remove the nuclear singularity of V_s.

5.2 Dimension-free energy cost

Lemma 5.2 (Energy cost of a data event). Suppose \Psi is an eigenstate of its sector Hamiltonian with energy e_\Psi, where 0\le e_\Psi-E\le D_0. In particular, e_\Psi=E_n for a sector ground state. Suppose further that

\sum_{h=j}^{m-1}\ell_h^{-2}\le C_\ell\ell_j^{-2}

with a fixed numerical C_\ell. This holds for the dyadic scales \ell_h=r_h^{1.01}, r_{h+1}=2r_h, with C_\ell=(1-2^{-2.02})^{-1}. If A\in\mathcal F_j has probability p=P(A)>0, put p_A(x)=P(A\mid x) and

\Psi_A=\sqrt{p_A(x)/p}\,\Psi.

Then \Psi_A is a normalized antisymmetric form-domain vector, its raw position-and-spin law is the raw marginal of P conditioned on A, and

q_n[\Psi_A]\le e_\Psi+C\ell_j^{-2}\log^5(e/p) \le E+D_0+C\ell_j^{-2}\log^5(e/p). \tag{5.4}

The constant depends only on C_\ell and the chosen noise law, not on n, the number of arrays, or the nuclear system. The same assertion holds for an event of one unordered observation at any width \ell, using \ell in place of \ell_j. No upper bound on the particle number in terms of the nuclear charge is needed.

Proof. In labeled observation coordinates place the sorting map inside the indicator of A. The translated product density is continuously differentiable in L^1, since \zeta is smooth and compactly supported. Hence p_A is continuously differentiable even for a Borel event. The scalar translation score is

S(u)=-\frac{\zeta'(u)}{\zeta(u)} =\frac{2u}{(1-u^2)^2},\qquad |u|<1.

Its law is symmetric and centered. It satisfies \|S(U)\|_q\le Cq^2 for q\ge2: indeed, T=(1-U^2)^{-1} has a finite exponential moment of every order less than one, so integration of its exponential tail gives \|T\|_q\le Cq, while |S(U)|\le2T^2.

For a unit vector v\in\R^{3n} the directional derivative of the likelihood pairs the event indicator with

Q_v=\sum_{h=j}^{m-1}\sum_{i=1}^n\sum_{b=1}^3 \ell_h^{-1}v_{i,b}S(U_{hi,b}).

Multiplication by independent random signs preserves the joint law of the independent symmetric scores. For deterministic coefficients,

\prod_\alpha\cosh(sc_\alpha) \le\exp\!\left(\frac{s^2}{2}\sum_\alpha c_\alpha^2\right)

gives the Gaussian tail estimate and consequently \|\sum_\alpha\epsilon_\alpha c_\alpha\|_q \le C\sqrt q(\sum_\alpha c_\alpha^2)^{1/2}. Conditioning on the scores and then using the triangle inequality in L^{q/2} yields

\|Q_v\|_q\le Cq^{5/2} \left(\sum_{h,i,b}\ell_h^{-2}v_{i,b}^2\right)^{1/2} \le Cq^{5/2}\ell_j^{-1}.

The identity \sum_{i,b}v_{i,b}^2=1 and the geometric square-sum bound are precisely what avoid factors depending on dimension or on the number of observations.

Hölder’s inequality at fixed x gives |D_vp_A(x)|\le Cq^{5/2}\ell_j^{-1}p_A(x)^{1-1/q}. For p_A(x)>0 choose q=\max\{2,\log(e/p_A(x))\} and then take the supremum over unit vectors. At a zero the gradient of the nonnegative differentiable function p_A vanishes. Therefore

|\nabla p_A|\le C\ell_j^{-1}p_A\log^{5/2}(e/p_A), \tag{5.5}

with right side zero at p_A=0.

Regularize the square root by \sqrt{p_A+\eta}. Since \sqrt u\log^{5/2}(e/u) is bounded on [0,1], these functions have a common Lipschitz bound. Their uniform limit \sqrt{p_A} is Lipschitz. Its gradient vanishes almost everywhere on its zero set, and the ordinary chain rule applies elsewhere. Thus

\left|\nabla\sqrt{p_A/p}\right|^2 \le C\ell_j^{-2}\frac{p_A}{p}\log^5(e/p_A).

The permutation sum in (5.3) shows that p_A is invariant under raw particle permutations and is spin independent. The bounded Lipschitz multiplier therefore preserves antisymmetry and the form domain. Its squared norm and its raw law are as claimed by the definition of p_A.

Lemma 2.4, applied with eigenvalue e_\Psi, now gives

q_n[\Psi_A]-e_\Psi \le C\ell_j^{-2}\E_P[\log^5(e/p_A(x))\mid A].

Under this conditional law,

P\{p_A(x)<e^{-u}\mid A\} =p^{-1}\E_P[p_A\1_{\{p_A<e^{-u}\}}] \le\min\{1,e^{-u}/p\}\qquad(u\ge0).

Integration of this tail, split at \log(e/p), bounds the fifth moment by C\log^5(e/p) and proves (5.4). The proof for a single array is identical with the square-sum constant equal to one.

5.3 Transfer to a fresh patch

The following quantitative formulation isolates exactly the local screening estimates needed by both applications. It allows either a patch containing singular nuclei or a patch containing none. The fine density below is the actual sum of packets around retained raw particles, not its conditional average.

Lemma 5.3 (Averaged field transfer). Fix a point y where V_s(y) is finite and a length a>0. Let A\in\mathcal F_j have positive P-probability, and let Q be P conditioned on A, extended by fresh localization labels. Its raw marginal is the law of \Psi_A from Lemma 5.2. Let X denote the fresh patch data, and let \rho_X^c be the conditional density of core particles under this tilted localization law. Partition the remaining raw particles into retained and deleted particles. Let

\sigma=\sum_{i\ {\rm retained}}\vartheta_b(\cdot-x_i),\qquad h_X=V_s-K*\rho_X^c-K*\rho_X,\qquad W_X=V_c+h_X,

where \vartheta_b is the radial probability kernel of Lemma 3.6, supported in B(0,\sqrt3b), and \rho_X\ge0 is a measurably chosen patch comparison density. Assume \rho_X and \sigma belong to L^{5/3} and have compact support for almost every patch datum. Put t=t_y, \tau=t/a, and \beta=b/a, and suppose 0<t,b\le a/10. Assume the following estimates, with fixed constants:

  1. 1.

    The master width z\mapsto t_z is Lipschitz with constant at most 1/2. The raw one-particle density \rho_{\Psi_A} satisfies

    \int_{B(y,4a)}\rho_{\Psi_A}^{5/3}\le Ca^{-7}.
  2. 2.

    Deleted particles have |x_i-y|\ge ca, and their count obeys \E_Q n_{\rm del}\le Ca^{-3}\sqrt\beta.

  3. 3.

    For some \varepsilon_a\ge0,

    \E_Q D(\rho_X-\sigma)\le Ca^{-7}\varepsilon_a^2.
  4. 4.

    On B(y,t) either the source-free bound \rho_X\le Ca^{-6} holds, or

    \rho_X=k(W_X)_+^{3/2},\qquad W_X\le V_{\rm loc}+Ca^{-4},\qquad V_{\rm loc}(z)=\sum_\alpha\frac{q_\alpha}{|z-R_\alpha|}, \qquad\sum_\alpha q_\alpha\le Ca^{-3},

    with q_\alpha\ge0. The latter alternative permits arbitrary locations of the local nuclei.

Then the two expectation towers are

\E_Q(K*\mu_j)(y)=\E_Q P^{\rm ms}(y),\qquad \E_Q(K*\rho_X^c)(y)=\E_Q P^c(y), \tag{5.6}

where P^{\rm ms} is the potential of the raw master packets and P^c is the raw core potential. Moreover,

\begin{split} |\E_Q(H_j-h_X)(y)|\le Ca^{-4}\big[& \tau^{1/5}+\beta^{1/5}+\sqrt\beta +\varepsilon_a\tau^{-1/2}\\ &+R(\tau)+(\tau+\sqrt3\beta)^{1/5}\big], \end{split} \tag{5.7}

where R(\tau)=\tau^2 in the source-free alternative and R(\tau)=\tau^2+\tau^{1/2} in the nuclear alternative. Thus the common upper bound R(\tau)\le C\tau^{1/2} is always available. All constants are independent of the number of particles; they depend only on the constants in the displayed hypotheses.

Proof. Write

P^{\rm raw}(y)=\sum_iK(y-x_i),\qquad P^{\rm ms}(y)=\sum_i(K*\mathcal K_{x_i})(y),\qquad P^{\rm raw}=P^c+P^{\rm ret}+P^{\rm del}.

The first identity in (5.6) follows by multiplying the original P-conditional expectation defining \mu_j by \1_A, using A\in\mathcal F_j, and dividing by P(A). The fresh labels do not alter this expectation. For the second identity, condition the raw-plus-label marginal of Q on X. That marginal is exactly the localization law of \Psi_A; the original observations can be integrated out. Tonelli justifies both identities initially for nonnegative potentials. In particular the first tower is under the original observation law, while the second uses the fresh tilted patch law.

Subtracting the definitions of H_j and h_X, and then using these towers, gives the exact algebraic identity

\begin{split} \E_Q(H_j-h_X)(y)=\E_Q\big[& (P^{\rm raw}-P^{\rm ms})-P^{\rm del}\\ &-(P^{\rm ret}-K*\sigma)+K*(\rho_X-\sigma)\big](y). \end{split} \tag{5.8}

The estimates below also establish finiteness of all terms, so this subtraction involves no difference of infinite expectations.

For 0<u\le4a, the local density bound and Hölder’s inequality give

\begin{split} \E_Q\sum_{|x_i-y|<u}K(y-x_i) &\le\left(\int_{B(y,4a)}\rho_{\Psi_A}^{5/3}\right)^{3/5} \left(\int_{|z|<u}|z|^{-5/2}\dd z\right)^{2/5}\\ &\le Ca^{-4}(u/a)^{1/5}. \end{split} \tag{5.9}

The complementary raw potential is bounded by n/(4a). By radial smearing, P^{\rm raw}-P^{\rm ms}\ge0 and only centers with |x_i-y|\le t_{x_i} can contribute. Lipschitz continuity of the width implies |x_i-y|\le t_y+|x_i-y|/2, hence these centers lie in B(y,2t). Equation (5.9) bounds its mean by Ca^{-4}\tau^{1/5}. The same Newton comparison for each fine packet gives

0\le\E_Q(P^{\rm ret}-K*\sigma)(y) \le Ca^{-4}\beta^{1/5}.

The distance and count assumptions for the deleted particles give \E_Q P^{\rm del}(y)\le Ca^{-4}\sqrt\beta.

For the signed density difference take v_t(z)=\min\{|y-z|^{-1},t^{-1}\}. This is in \dot H^1 and

\|\nabla v_t\|_2^2=4\pi\int_t^\infty r^{-2}\dd r=4\pi/t.

Lemma 3.1 and Cauchy–Schwarz in probability give

\E_Q\left|\int v_t(\rho_X-\sigma)\right| \le Ct^{-1/2}\sqrt{\E_QD(\rho_X-\sigma)} \le Ca^{-4}\varepsilon_a\tau^{-1/2}.

It remains to control the two nonnegative remainders of the truncation inside B(y,t). In the source-free case,

\int_{B(y,t)}K(y-z)\rho_X(z)\dd z \le Ca^{-6}t^2=Ca^{-4}\tau^2.

For the nuclear alternative, weighted convexity gives, with Q_{\rm loc}=\sum_\alpha q_\alpha,

V_{\rm loc}^{3/2} \le Q_{\rm loc}^{1/2}\sum_\alpha q_\alpha|z-R_\alpha|^{-3/2}.

The assertion is read as zero if Q_{\rm loc}=0. Uniformly in R\in\R^3,

\int_{B(y,t)}\frac{\dd z}{|y-z|\,|z-R|^{3/2}} \le Ct^{1/2}.

For completeness, apply Hölder to the second factor with any exponent q\in(3/2,2) and to the first with conjugate exponent q'\in(2,3). Integrals of these radial decreasing powers over a ball are no larger than their centered-ball integrals; the powers of t combine to t^{1/2}. Since \rho_X\le C(a^{-6}+V_{\rm loc}^{3/2}), its remainder is at most

C\big(a^{-6}t^2+Q_{\rm loc}^{3/2}t^{1/2}\big) \le Ca^{-4}(\tau^2+\tau^{1/2}).

This proves the asserted nuclear bound even when a nucleus lies at y; only V_s(y), not the unsmoothed V(y), was required finite.

For \sigma, only packets centered within t+\sqrt3b of y meet the truncation ball. Extend each such packet’s kernel integral to all space and use radial smearing to bound it by its raw point potential. Equation (5.9) bounds the mean remainder by Ca^{-4}(\tau+\sqrt3\beta)^{1/5}. The truncated \sigma potential is integrable, being at most n/t. Together with Coulomb duality and the just obtained remainder bound, this also proves integrability of the full \rho_X potential. The raw and core potentials were already integrable by (5.9). Hence all the preceding subtractions are valid. Adding the four estimates in (5.8) proves (5.7).

In both later applications the screening estimates supply \varepsilon_a=a^{.01} and \beta=a^{.2}. The master geometry supplies \tau\ge ca^w, with w=10^{-5}, and an upper bound on \tau tending to zero with the outer small parameter. Consequently

a^{.01}\tau^{-1/2}\le Ca^{.01-w/2},\qquad .01-w/2=.009995>0,

and every term in the bracket in (5.7) tends to zero uniformly in the participating bands. Thus the transfer is o(a^{-4}). The specific lower probability thresholds for the events are used in those applications to verify the screening hypotheses through (5.4); no probability threshold is needed for the transfer identity itself.

5.4 Maxima before conditional averaging

The next local rule joins fields on actual open neighborhoods. It will be used in both propagation arguments after their common singularities have been canceled.

Lemma 5.4 (Maximum of weak subsolutions). Let \mathcal O\subset\R^3 be open, let g be locally bounded, and let F(y,t) be measurable in y, continuous in t, and bounded on compact spatial sets and bounded ranges of t. If finitely many functions v_i\in C(\mathcal O)\cap H^1_{\mathrm{loc}}(\mathcal O) satisfy

\Delta v_i\ge g+F(y,v_i)

in distributions, their maximum satisfies the same inequality with its own value in the reaction term. The assertion also holds for functions v_i=V+a_i with continuous locally H^1 offsets a_i, when all inequalities have the common singular term -4\pi\nu and the reaction vanishes in a neighborhood of \operatorname{supp}\nu.

Proof. It suffices to consider two functions. For a nonnegative compactly supported smooth test \varphi, choose an increasing Lipschitz function \theta_\eta that is zero on (-\infty,0] and one on [\eta,\infty). Test the first inequality with \theta_\eta(v_1-v_2)\varphi and the second with (1-\theta_\eta(v_1-v_2))\varphi. These nonnegative compactly supported H^1 tests are legitimate by mollification, since the right sides are bounded on their support. The sum of the left sides is

\begin{align*} &-\int\bigl[\theta_\eta(v_1-v_2)\nabla v_1 +(1-\theta_\eta(v_1-v_2))\nabla v_2\bigr]\cdot\nabla\varphi\\ &\hspace{8mm} -\int\theta_\eta'(v_1-v_2)|\nabla(v_1-v_2)|^2\varphi.\end{align*}

The second term is nonpositive. Deleting it and letting \eta\downarrow0 gives the gradient of \max(v_1,v_2) by the Sobolev positive-part formula. Dominated convergence gives the reaction at the maximum; the reactions agree at ties. Induction proves the finite version.

For the last assertion subtract V in each inequality. The singular measures cancel, and the reaction for the offsets becomes F(y,V(y)+a_i(y)). It is locally bounded: it vanishes near every nuclear point, and V is smooth off \operatorname{supp}\nu. Apply the first assertion to the offsets and then add V back.

6 Electron counts in large nuclear voids

The local count bound of Lemma 4.4 controls the electrons in each annulus whose radius is comparable to its distance from the nuclei. Summing that bound over arbitrarily many annuli would lose a factor equal to the number of scales. We first remove this loss in a nuclear void. A geometric decomposition will then reduce the exterior region of an arbitrary molecule to only O(M) such voids.

Throughout this section \Psi is the normalized eigenstate in the largest strictly bound sector, and E=E_N=\inf_{j\ge0}E_j, as in Lemma 2.3. Expectations without an additional subscript refer to its position law, with spins summed. Constants may depend on the fixed numbers A=40 and L=10^6, but on no feature of the molecule.

Lemma 6.1 (A large nuclear void). There are universal constants t_0,C>0 with the following property. Let O\in\R^3, t\ge t_0 and T=2^Jt, where J\ge1 is an integer. Suppose that at least one nucleus lies in B(O,t/100) and that every nucleus satisfies

|R_m-O|<t/100\qquad\text{or}\qquad |R_m-O|>100T.

Then

\left\|\#\{i:t\le |x_i-O|<T\}\right\|_{L^2(\Psi)}\le C. \tag{6.1}

Proof. Translate O to the origin. Put u_i=|x_i|, s_k=2^kt and

n_k=\#\{i:s_k\le u_i<2s_k\},\qquad L_{\mathrm{ann}}=\sum_{k=0}^{J-1}n_k.

For s_k/4\le |v|\le8s_k, the nuclear assumptions give c s_k\le d(v)\le C s_k, where d(v) is the distance to the nearest nucleus. Indeed, the inner nucleus supplies the upper bound; the inner and outer alternatives supply the lower bound. Choose t_0 so large that d(v)/L>1 on all these annuli. Lemma 4.1 then gives a_v=d(v)/L\asymp s_k/L.

Each enlarged annulus is covered by a universally bounded number of local balls B(v,a_v) with comparable scales. For example, take a maximal set of centers in the annulus separated by c s_k/L, with c small; the disjoint balls of half that radius give the bound on their number. Lemma 4.4, applied to any \delta-state \omega in the fixed sector N, consequently yields

\|n_k\|_{L^2(\omega)} +\|n_{\mathrm{neigh},k}\|_{L^2(\omega)} \le C(1+\sqrt{\delta s_k}), \qquad n_{\mathrm{neigh},k}=\#\{i:s_k/2\le u_i\le4s_k\}. \tag{6.2}

This proves the result when J is bounded. We may therefore assume that J exceeds a fixed sufficiently large integer.

A weighted eigenstate inequality. Choose 0\le\chi\le1 supported in (32t,T/32), equal to one on [64t,T/64], and satisfying |\chi'(u)|\le C/u, |\chi''(u)|\le C/u^2. Such a function is obtained by multiplying a fixed cutoff at scale t by a fixed cutoff at scale T. Set w(u)=u\chi(u)^2. It is a bounded smooth multiplier that vanishes near the origin. For each weighted index, integration by parts gives

\begin{align*} \operatorname{Re}\langle w(u_i)\Psi,-\tfrac12\Delta_i\Psi\rangle &=\tfrac12\int w(u_i)|\nabla_i\Psi|^2 -\tfrac14\int \Delta_iw(u_i)|\Psi|^2\\ &\ge-C\E\frac{\1_{\{t\le u_i<T\}}}{u_i}.\end{align*}

These identities hold first after form-domain approximation and then by continuity, since w and its derivatives are bounded for fixed t,T. Summing the last bound costs at most C\sum_k s_k^{-1}\E n_k\le C/t\le C by (6.2) with \delta=0. After fixing x_i and its spin, the remaining Hamiltonian has energy at least E_{N-1}\ge E. Its contribution against the nonnegative weight w(u_i) is therefore nonnegative. Testing the eigen-equation with \sum_iw(u_i)\Psi shows that weighted repulsion minus attraction is at most C.

For an electron in a shell meeting the support of \chi, keep only its repulsion against electrons at radius <t, at radius \ge T, and in shells l\le k-5. Dropping the other repulsions preserves the upper bound. Write

P_k=\sum_{\substack{0\le l<J\\l\le k-5}}n_l, \qquad q=\nu(B(0,t))-\#\{i:u_i<t\},

and define the exterior signed potential at the origin by

B=\int_{|R|>100T}\frac{d\nu(R)}{|R|} -\sum_{u_i\ge T}\frac1{u_i}.

For each such k, use a cut that is full out on [s_k/2,4s_k], supported in [s_k/4,8s_k], and has gradients bounded by C/s_k. Let X_k be its out data as in Lemma 3.4; a bar will mean conditional expectation given X_k in this paragraph and below. Set

\varphi(v)=V(v)-\sum_{u_i<t}\frac1{|v-x_i|} -\sum_{u_i\ge T}\frac1{|v-x_i|}, \qquad \psi_k(v)=\overline{\varphi(v) -\sum_{l\le k-5}\sum_{i\in l}\frac1{|v-x_i|}}.

Every supported shell satisfies 32t\le s_k\le T/64. All sources defining \psi_k are outside \{s_k/4<|v|<8s_k\}: prefix electrons have radius <s_k/16, inner electrons have radius <t\le s_k/32, and exterior electrons have radius \ge T\ge64s_k. Thus \psi_k has a continuous harmonic version on this annulus. Newton’s sphere-average formula gives

\langle\psi_k\rangle_u =\frac{\bar q-\bar P_k}{u}+\bar B, \qquad s_k/4<u<8s_k, \tag{6.3}

where \langle F\rangle_u=(4\pi u^2)^{-1}\int_{|v|=u}F(v)\,dS(v). The shell-k positions are all recorded in X_k. We may therefore condition the selected interaction terms while retaining their weights. The preceding eigenstate inequality becomes

-\E\sum_k\sum_{i\in k}u_i\chi(u_i)^2\psi_k(x_i)\le C, \tag{6.4}

where k ranges over the supported shells. Conditional harmonic versions and sphere averages are justified directly by the positive distance to these sources and their fixed finite total masses.

A size-biased law for one shell. Fix a supported k. Choose a smooth function b_k, equal to one on [s_k,2s_k], supported in (s_k/2,4s_k), with 0\le b_k\le1 and |b_k'|\le C/s_k. Put

S_k=\sum_i b_k(u_i)^2,\qquad m_k=\E S_k.

Then n_k\le S_k\le n_{\mathrm{neigh},k}. If m_k=0, every shell-k contribution vanishes and can be omitted. Otherwise define

\Psi_k=\sqrt{S_k/m_k}\,\Psi,

and denote its expectation and L^2 norm by \E_k and \|\cdot\|_{2,k}. The square root of a sum of squares is Lipschitz, and, off its zero set,

|\nabla\sqrt{S_k}|^2 =\frac{\sum_i b_k(u_i)^2|\nabla b_k(u_i)|^2}{S_k} \le Cs_k^{-2}\1_{\{n_{\mathrm{neigh},k}>0\}} \le Cs_k^{-2}n_{\mathrm{neigh},k}.

Its gradient is zero almost everywhere on its zero set. The multiplier identity in Lemma 2.4 shows that \Psi_k is a \delta_k-state, with

\delta_k\le \frac{C\E n_{\mathrm{neigh},k}}{s_k^2m_k}. \tag{6.5}

The random variable S_k is X_k-measurable, because its support is inside the full-cut zone. The joint position and cut-label law changes by the factor S_k/m_k. Its conditional position law given X_k is therefore unchanged on S_k>0. In particular all the barred fields and counts above have the same conditional versions under this new law. This permits us to use the local estimates for \Psi_k without changing the fields in (6.4).

A positive bound and a signed harmonic comparison. On the broad annulus of harmonicity, the base and prefix sources lie outside the exclusion defining J_v. Its radius Aa_v is a fixed small fraction of |v|, since A/L is small. The additional electrons subtracted by J_v give the upper bound

\psi_k(v)\le\overline{J_v} +C\sum_{l\ge k-4}\frac{\bar n_l}{\max(s_l,s_k)}. \tag{6.6}

For comparable shells the exclusion supplies the denominator c s_k; for sufficiently larger shells radial separation supplies c s_l. These are precisely the electrons absent from the definition of \psi_k.

The cut defining X_k is covered by a universally bounded number of cells at scales comparable to s_k/L. Its gradients are C/s_k and a_v\ge1 there, so it meets the initial-cut hypothesis of Lemma 4.2. For targets in the same broad annulus, that lemma and (6.2), now applied under \Psi_k, give

\|(\psi_k(v))_+\|_{2,k} \le \frac{C(1+\sqrt{\delta_k s_k})}{s_k}.

Conditional Jensen’s inequality bounds \|\bar n_l\|_{2,k} by \|n_l\|_{2,k}. Thus the added count terms are bounded by the convergent series

C\sum_{l\ge k-4}\frac{1+\sqrt{\delta_k s_l}}{s_l} \le \frac{C(1+\sqrt{\delta_k s_k})}{s_k}.

Positive parts of harmonic functions are subharmonic. Covering the compact annulus \{s_k/2\le|v|\le3s_k\} by a fixed number of interior balls in the broad annulus, and using the ball submean inequality and Minkowski’s inequality, consequently gives

A_k=s_k\sup_{s_k/2\le|v|\le3s_k}(\psi_k(v))_+, \qquad \|A_k\|_{2,k}\le C(1+\sqrt{\delta_k s_k}). \tag{6.7}

The function A_k/s_k-\psi_k is nonnegative and harmonic in the interior of this latter annulus. Its value at any point of a sphere s_k\le u\le2s_k is at least c times its sphere mean, for one universal c>0. Indeed, after scaling, a bounded chain of interior balls joins any two points of these spheres; on a ball, this comparison follows by comparing its Poisson kernels on a smaller concentric ball. Applying this comparison and (6.3) gives

u\psi_k(v)\le C A_k+c(\bar q+u\bar B-\bar P_k), \qquad |v|=u\in[s_k,2s_k]. \tag{6.8}

The negative prefix term retains a fixed positive coefficient.

The endpoint fields. Put s_-=2t and s_+=T/2. For a supported shell and u\in[s_k,2s_k],

\bar q+u\bar B =(1-\vartheta(u))(\bar q+s_-\bar B) +\vartheta(u)(\bar q+s_+\bar B), \quad \vartheta(u)=\frac{u-s_-}{s_+-s_-}, \quad 0\le\vartheta(u)\le C s_k/T.

At either endpoint all base sources are outside the J_v exclusion. Sphere averaging \bar\varphi and adding back the annular electrons therefore yields

\bar q+s\bar B\le s\langle(\overline{J_v})_+\rangle_s +Cs\sum_l\frac{\bar n_l}{\max(s_l,s)}, \qquad s\in\{s_-,s_+\}. \tag{6.9}

Indeed, the omitted contribution of an annular electron is nonnegative and at most its full Coulomb kernel. The latter has sphere average 1/\max(s,u_i)\le1/\max(s,s_l) for an electron in shell l. For these targets a_v\asymp s/L. The initial cut is still at scale s_k/L, so the energy parameter in Lemma 4.2 satisfies e_*\le C(\min(s,s_k)^{-1}+\delta_k). The precise consequence is

\left\|s\langle(\overline{J_v})_+\rangle_s\right\|_{2,k} \le C\sqrt{\frac{s}{\min(s,s_k)}+\delta_k s}. \tag{6.10}

At s=s_- this is at most C(1+\sqrt{\delta_k s_k}). At s=s_+ the interpolation weight gives instead

C\frac{s_k}{T}\sqrt{\frac{T}{s_k}+\delta_k T} \le C\left(\sqrt{\frac{s_k}{T}} +\sqrt{\delta_k s_k}\sqrt{\frac{s_k}{T}}\right) \le C(1+\sqrt{\delta_k s_k}).

The inner endpoint count term in (6.9) has norm at most

C\sum_l2^{-l}(1+\sqrt{\delta_k2^lt}) \le C(1+\sqrt{\delta_k t}).

For the outer endpoint, s_+/\max(s_l,s_+)\le1; we retain its contribution as C(s_k/T)\bar L_{\mathrm{ann}}. Thus (6.8) supplies a nonnegative, X_k-measurable random variable D_k, the same for every electron in shell k, such that

u_i\psi_k(x_i)\le D_k+C\frac{s_k}{T}\bar L_{\mathrm{ann}}-c\bar P_k, \qquad \|D_k\|_{2,k}\le C(1+\sqrt{\delta_k s_k}). \tag{6.11}

Summation over shells. Changing to the size-biased law and using (6.5), s_k\ge1, and m_k\le\E n_{\mathrm{neigh},k}, gives

\begin{align*} \E[n_kD_k]&\le m_k\E_kD_k \le C m_k(1+\sqrt{\delta_k s_k})\\ &\le C\left(m_k+ \sqrt{m_k\E n_{\mathrm{neigh},k}/s_k}\right) \le C\E n_{\mathrm{neigh},k}. \tag{6.12}\end{align*}

The neighbor annuli for supported k lie inside \{t\le|x|<T\} and have bounded overlap, so these costs sum to C\E L_{\mathrm{ann}}. For the outer term, n_k is X_k-measurable and the tower property gives

\begin{align*} \sum_k\frac{s_k}{T}\E[n_k\bar L_{\mathrm{ann}}] &=\sum_k\frac{s_k}{T}\E[n_kL_{\mathrm{ann}}]\\ &\le\|L_{\mathrm{ann}}\|_2 \sum_k\frac{s_k}{T}\|n_k\|_2 \le C\|L_{\mathrm{ann}}\|_2.\end{align*}

Here the unconditioned norms use (6.2) with \delta=0, and \sum_k s_k/T\le1. Insert (6.11) into (6.4). The weights W_k=\sum_{i\in k}\chi(u_i)^2 are X_k-measurable and satisfy 0\le W_k\le n_k. Removing the bar on P_k by the tower property, we obtain

\E\sum_kW_kP_k\le C(1+\|L_{\mathrm{ann}}\|_2). \tag{6.13}

Let I_{\mathrm{mid}} consist of the shells entirely contained in [64t,T/64], and set L_{\mathrm{mid}}=\sum_{k\in I_{\mathrm{mid}}}n_k. On these shells W_k=n_k. The sum on the left of (6.13) therefore includes all products n_kn_l with k,l\in I_{\mathrm{mid}} and l\le k-5. For every omitted close pair |k-l|<5, including k=l, use the tilt at k and (6.2) to obtain

\E n_kn_l\le m_k\E_kn_l \le C m_k(1+\sqrt{\delta_k s_l}) \le C\E n_{\mathrm{neigh},k}.

The last step uses s_l\asymp s_k and the same calculation as (6.12). Each k has only a bounded number of such neighbors. Thus the close-pair costs sum to C\E L_{\mathrm{ann}}, rather than a cost proportional to J. Expanding L_{\mathrm{mid}}^2 now gives

\E L_{\mathrm{mid}}^2\le C(1+\|L_{\mathrm{ann}}\|_2).

Only a fixed number of endpoint shells were omitted, so \|L_{\mathrm{ann}}-L_{\mathrm{mid}}\|_2\le C by (6.2). Consequently X=\|L_{\mathrm{ann}}\|_2 satisfies X^2\le C(1+X), proving the lemma.

Lemma 6.2 (Exterior count). There is a universal constant C such that, for 0<s\le 1,

\E\#\{i:a_{x_i}\ge s\}\le CMs^{-3}. \tag{6.14}

The constant is independent of the charges and the distances between nuclei.

Proof. Write \mathcal R=\{R_1,\ldots,R_M\} and d(x)=\operatorname{dist}(x,\mathcal R). We use d(x)\le L a_x from Lemma 4.1. For a Borel set B, write n(B)=\#\{i:x_i\in B\}. The local count bound (4.36), applied with \delta=0, gives

\E n(B(y,a_y)) \le C\max\{a_y^{-3},1\}. \tag{6.15}

We first prove that

\E n(\{d\ge U\})\le CM \tag{6.16}

for a sufficiently large universal constant U. A direct summation of local bounds over all large distance scales would give an infinite series. We instead group scales into a bounded number of annuli to which Lemma 6.1 applies.

Nested sets of nuclear representatives. Fix

h=12,\qquad \varepsilon=2^{1-h}=\frac1{2048},\qquad D_0=1000,\qquad q=10.

Thus

\varepsilon<\frac1{200},\qquad D_0-\varepsilon>400, \qquad D_0>3\varepsilon,\qquad 2^q>D_0.

Choose an integer j_0 such that 2^{j_0}/L\ge1 and 2^{j_0-1} exceeds the lower threshold for the inner radius in Lemma 6.1. Set U=2^{j_0}. Since the nuclei are distinct, there is an integer l_0<j_0-h such that \mathcal R is 2^{l_0}-separated. Put P_{l_0}=\mathcal R. For each l>l_0, choose a maximal 2^l-separated subset P_l\subset P_{l-1}, where separated means that distinct points have distance at least 2^l.

For each p\in P_{l-1} choose a parent \pi_l(p)\in P_l, keeping \pi_l(p)=p for p\in P_l. Maximality permits this choice with |p-\pi_l(p)|<2^l whenever p is removed. Composing these maps gives an ancestor \alpha_l(R)\in P_l for every original nucleus R, and

|R-\alpha_l(R)|<2^{l+1}. \tag{6.17}

Indeed, the accumulated displacement is less than \sum_{k=l_0+1}^l2^k<2^{l+1}; at l=l_0 it is zero. Every representative is an original nucleus, and a removed nucleus never reappears in the nested sets.

For j\ge j_0, put u_j=2^j. Choose a nearest nucleus R(x) measurably, breaking ties by the least index. Assign a point of the dyad u_j\le d(x)<2u_j to c=\alpha_{j-h}(R(x))\in P_{j-h}, and denote its assigned set by A_{j,c}. These are Borel sets, disjoint at each scale, and

|R(x)-c|<\varepsilon u_j,\qquad A_{j,c}\subset B(c,(2+\varepsilon)u_j). \tag{6.18}

Only finitely many crowded pairs. Call (j,c) crowded if there is a distinct w\in P_{j-h} with |w-c|\le D_0u_j; otherwise call it isolated. We claim that the number of crowded pairs is at most CM. For each crowded pair choose one witness w. The points c and w cannot both survive to P_{j+q}, since that set is 2^{j+q}-separated and 2^{j+q}>D_0u_j. Let r be the first level at which either endpoint is removed, and charge (j,c) to one such removal event (r,p), where p\in P_{r-1}\setminus P_r. Then

j-h<r\le j+q, \qquad\text{or equivalently}\qquad r-q\le j\le r+h-1. \tag{6.19}

A fixed removal event can therefore receive charges from at most q+h levels j. At any one of these levels, a center c charging (r,p) is either p itself or has p as its witness. In either case, c\in P_{j-h}\cap\overline B(p,D_0u_j). Such centers are 2^{j-h}-separated. The disjoint balls of radius 2^{j-h-1} around them lie in the ball of radius D_0u_j+2^{j-h-1} around p, so their number is at most (1+2D_0 2^h)^3. This is a fixed constant. There are at most M-1 removal events, since the nested sets eventually contain one nucleus. Consequently

\#\{(j,c):j\ge j_0,\ (j,c)\text{ is crowded}\}\le CM. \tag{6.20}

Simultaneous removals cause no difficulty: the charge uses just one of the two removed endpoints.

Each crowded assigned set has bounded expected particle count. To see this, choose a maximal u_j/(2L)-separated subset of A_{j,c}. By (6.18), a volume comparison bounds its cardinality by CL^3. Its balls of radius u_j/(2L) cover A_{j,c}. At every center y we have a_y\ge d(y)/L\ge u_j/L\ge1, so these covering balls are contained in B(y,a_y). Equation (6.15) therefore gives

\E n(A_{j,c})\le C. \tag{6.21}

Together, (6.20) and (6.21) show that all crowded assigned sets cost at most CM expected particles.

Isolated runs give empty annuli. For a fixed nucleus c, the levels j\ge j_0 at which c\in P_{j-h} form an initial integer interval, possibly empty or infinite. Removing its crowded levels leaves consecutive runs of isolated levels. The number of these runs is at most one plus the number of crowded levels for c. Summing over c and using (6.20), the total number of isolated runs is at most CM.

At an isolated level j for c, every original nucleus R satisfies one of the two alternatives

|R-c|<\varepsilon u_j \qquad\text{or}\qquad |R-c|>(D_0-\varepsilon)u_j. \tag{6.22}

Indeed, if \alpha_{j-h}(R)=c, the first alternative follows from (6.17). Otherwise isolation gives |\alpha_{j-h}(R)-c|>D_0u_j, and the ancestor offset gives the second alternative.

The alternative for a fixed nucleus cannot change between consecutive isolated levels j and j+1 for the same center c. A nucleus near c at level j remains too close to satisfy the far alternative at j+1. Conversely, a nucleus far at j could be near at j+1 only if its fixed distance from c were both greater than (D_0-\varepsilon)u_j and less than 2\varepsilon u_j, which is impossible because D_0>3\varepsilon. Thus the set of near nuclei is constant throughout each isolated run. This argument permits ancestor maps to change and uses only the gap in (6.22).

Consider first a finite run j=a,\ldots,b and put

O=c,\qquad t=u_a/2,\qquad T=4u_b.

The near nuclei have distance less than \varepsilon u_a<t/100 from c. All other nuclei have distance greater than (D_0-\varepsilon)u_b>100T. There is a nucleus at c, and T/t=2^{b-a+3} is a power of two. By the choice of j_0, Lemma 6.1 applies. Every assigned point from this run belongs to its annulus, since c is itself a nucleus and

t\le u_a\le d(x)\le |x-c|<(2+\varepsilon)u_b<T.

It follows that the union of the assigned sets over this run has expected particle count at most C, independently of its length. For an infinite run, apply the same argument to each finite initial segment and then use monotone convergence for their increasing assigned unions. There are at most CM runs, so the total contribution of all isolated assigned sets is at most CM. Combined with the crowded sets, this proves (6.16).

The remaining distances. It remains to count particles with a_x\ge s and d(x)<U. For the part with d(x)<s, choose a maximal s/2-separated subset of \{d<s,\ a\ge s\}. Its centers lie in \bigcup_{m=1}^M B(R_m,s). Disjoint balls of radius s/4 around them show, by volume comparison, that there are at most CM centers. Their balls of radius s/2 cover the set and are contained in the corresponding local balls B(y,a_y), since a_y\ge s. Equation (6.15) bounds this contribution by CMs^{-3}.

For a distance dyad u\le d(x)<2u, choose a maximal u/(2L)-separated subset. Its centers lie in \bigcup_m B(R_m,2u), so there are at most CL^3M of them. Their local balls cover the dyad, because a_y\ge d(y)/L\ge u/L. Thus (6.15) bounds its expected count by

CM\max\{(u/L)^{-3},1\}.

Take u=2^ks for 0\le k\le K, where K is the least nonnegative integer such that 2^Ks\ge U. These dyads cover s\le d(x)<U. The sum of the inverse-cube terms is bounded by Cs^{-3}. For the constant terms with u<1, use 1\le u^{-3}; the number of remaining dyads, with 1\le u\le2U, is bounded by a universal constant. Their total contribution is therefore at most CMs^{-3}. Adding (6.16) proves (6.14).

7 Deterministic comparison fields

We now construct positive fields that can be compared across all the local scales. The construction uses only the nuclear measure. Its output is a family of continuous offsets satisfying a nonlinear subsolution inequality, together with a strictly positive gap when the scale doubles. The gap will allow the quantum field to replace a comparison field in the next stage of the proof.

Fix a nuclear system and a small parameter r_*>0. Its value in terms of the excess charge, together with the dyadic scales used for the observations, will be chosen in Section 8. Every smallness threshold for r_* in the present deterministic construction is universal and independent of the nuclear system.

Throughout this section, p=3/2, k=((5/3)\cT)^{-3/2}, and \cF=4\pi k. Recall that K(x)=|x|^{-1} and that a_x is the nuclear scale of Lemma 4.1. All constants in this section are independent of the nuclear configuration and charges. They may depend on the fixed localization constants and the smooth radial function g used for wave packets.

7.1 Global Thomas–Fermi fields

The variational and comparison framework for point and smoothed sources is classical [12, Theorems II.14, II.17–II.18, and IV.7–IV.10]. We give a proof on the Coulomb-space cone used here, including the decay needed for comparison on an unbounded domain. If \zeta is a finite sum of positive point charges and nonnegative smooth compactly supported radial charges, write V_\zeta=K*\zeta. A radial charge is specified by its center, profile, and total mass. Set

\mathcal X_+=\{\rho\ge0:\rho\in L^{5/3}(\mathbb R^3) \cap(\dot H^1(\mathbb R^3))^*\}.

By Lemma 3.1, the Coulomb energy of an element of this cone is the squared norm D(\rho)=\|\nabla K*\rho\|_2^2/(8\pi).

Lemma 7.1 (Global comparison problem). Let \zeta be as above, with total mass Q>0. The functional

\mathcal T_\zeta(\rho) =\cT\int\rho^{5/3}-\int V_\zeta\rho+D(\rho), \qquad \rho\in\mathcal X_+,

has a unique minimizer. Its field W=V_\zeta-K*\rho satisfies

\rho=kW_+^p,\qquad \Delta W=-4\pi\zeta+\cF W_+^p,\qquad W\ge0,\qquad \int\rho\le2Q. \tag{7.1}

The screening potential K*\rho is continuous and tends to zero at infinity. Consequently W tends to zero at infinity and is continuous away from point charges.

Proof. Smear the point charges at any fixed positive widths and leave the smooth charges unchanged. This decomposes V_\zeta=V_s+V_c with V_s\in\dot H^1 and compactly supported V_c\in L^{5/2}. Thus

\left|\int V_s\rho\right| \le C\|\nabla V_s\|_2\sqrt{D(\rho)},\qquad \left|\int V_c\rho\right| \le\|V_c\|_{5/2}\|\rho\|_{5/3}.

For the fixed source and smearing widths, both displayed potential norms are finite. Young’s inequality proves coercivity in both spaces defining \mathcal X_+. A bounded minimizing sequence has weakly convergent subsequences in these two reflexive spaces. Their limits agree as distributions, since both converge against compact smooth tests; nonnegativity passes to this limit. The two linear terms are weakly continuous in their respective spaces, and both positive terms are weakly lower semicontinuous. This proves existence. The strictly convex kinetic term proves uniqueness.

Nonnegative smooth compact variations give

d:=\tfrac53\cT\rho^{2/3}-V_\zeta+K*\rho\ge0 \quad\text{almost everywhere}.

For bounded smooth compactly supported \varphi, the variations (1+t\varphi)\rho are admissible for sufficiently small positive and negative t. Indeed |\varphi\rho|\le\|\varphi\|_\infty\rho, and positivity of the Coulomb kernel bounds its Coulomb energy. The nonnegative pairing property in Lemma 3.1 therefore justifies differentiating these variations and gives \int d\varphi\rho=0. Hence d\rho=0, proving the Euler equation in (7.1) and its distributional Laplacian.

To establish finite mass without assuming it, let the source components have centers R_m and masses Q_m, and put

U(x)=\sum_m\frac{Q_m}{|x-R_m|},\qquad w(x)=U(x)^{-1}.

Newton’s theorem gives V_\zeta\le U. Where \rho>0, the Euler equation gives K*\rho\le V_\zeta. For any ball B, multiply this inequality by 1_Bw\rho and restrict the screening integral below to B. Write q_m(x)=w(x)Q_m/|x-R_m|, so that \sum_mq_m=1. The triangle inequality gives

\frac{w(x)+w(y)}{|x-y|} \ge\sum_m\frac{q_m(x)q_m(y)}{Q_m}.

The resulting symmetrization and Cauchy–Schwarz yield, with m_B=\int_B\rho,

m_B\ge\frac12\sum_m\frac{(\int_Bq_m\rho)^2}{Q_m} \ge\frac{m_B^2}{2Q}.

All integrals in this calculation are local and finite; in particular w is bounded on B, and the local Coulomb energy is finite. Increasing B proves \int\rho\le2Q.

For completeness, L^1\cap L^{5/3} implies continuity and decay of the screening potential. The kernel restricted to a fixed ball belongs to L^{5/2}, so its pairing with translates of \rho is continuous. The complementary kernel contributes at most \|\rho\|_1/R when the cutoff radius is R. For fixed R, the local L^{5/3} norm of \rho on a ball whose center tends to infinity tends to zero. First letting the center tend to infinity and then R\to\infty proves decay.

Finally, (W+\varepsilon)_- is compactly supported away from point charges for every \varepsilon>0: W\to0 at infinity, and its positive Coulomb singularities dominate the continuous screening potential. On the support of this test \rho=0, and hence \Delta W\le0. Testing the equation gives \int|\nabla(W+\varepsilon)_-|^2\le0. The test is justified by compact H^1 approximation away from the singularities. Letting \varepsilon\downarrow0 proves W\ge0.

Lemma 7.2 (Point fields and mixtures). For one point charge Q>0 at R, the field in Lemma 7.1 satisfies

W(x)\ge c\min\left(\frac{Q}{|x-R|},|x-R|^{-4}\right). \tag{7.2}

For a single point charge or radial smooth charge of mass Q, its screening potential is bounded by CQ^{4/3}.

More generally, select source components of masses Q_i, truncate them to masses q_i\le Q_i, and put q=\sum_iq_i>0. Let W_i be the single-source field of mass q at the ith center with that source’s normalized profile. If W is the full-source field, then

\sum_i\frac{q_i}{q}W_i\le W. \tag{7.3}

Proof. For a single source, Newton’s theorem and the Euler equation give \rho(z)\le k(Q/|z-R|)^{3/2}. For every x,R and s>0,

\int_{B(x,s)}\frac{dz}{|x-z|\,|z-R|^{3/2}} \le Cs^{1/2}. \tag{7.4}

To see the uniformity in R, apply Hölder with exponent q_1\in(3/2,2) to the second factor and its conjugate q_1'\in(2,3) to the first. The integrals of both radial powers over B(x,s) are bounded by their integrals over centered balls of the same radius. Their powers of s combine to s^{1/2}. Split K*\rho(x) at s=Q^{-1/3}. The near part is at most CQ^{3/2}s^{1/2} by (7.4), and the far part at most 2Q/s by Lemma 7.1. Both are CQ^{4/3}.

For a point charge this gives W\ge Q/(2d) for d=|x-R|\le cQ^{-1/3}. Outside that sphere set v=\lambda d^{-4}. For sufficiently small universal \lambda>0,

\Delta v=12\lambda d^{-6}\ge \cF v^{3/2},

and its boundary value is below the preceding lower bound. On the exterior domain, testing the equation for v-W with (v-W-\varepsilon)_+ gives a nonpositive gradient square bounded below by zero. This test has compact support since both fields decay. Thus v\le W. Together with the inner estimate this proves (7.2).

For the mixture F=\sum_i(q_i/q)W_i, convexity gives

\Delta F\ge-4\pi\zeta_{\rm truncated}+\cF F^p \ge-4\pi\zeta+\cF F^p.

Compare with the equation for W and test with (F-W-\varepsilon)_+. The support is compact. Near a point charge whose mass was strictly decreased, F-W tends to -\infty, so the test vanishes there. If the masses agree, the singular terms cancel and the difference is locally H^1. The remaining density terms are locally in L^{5/3}, so compact H^1 approximation is valid. Monotonicity of the power gives F\le W.

7.2 Fields adapted to the nuclear scale

Fix a sufficiently small constant c_1\in(0,1/100). Smear the mth nucleus with the radial probability g_{c_1a_{R_m}}^2 and denote the resulting density by \nu_s. Put

V_s=K*\nu_s,\qquad V_c=V-V_s\ge0. \tag{7.5}

The subscript c records the part confined near the nuclei. A nucleus contributing to V_c(x) lies within 2c_1a_x of x. Its scale is comparable to a_x, and the total contributing charge is at most a_x^{-3}. Therefore

\nu_s(x)\le Ca_x^{-6},\qquad V_c\in L^{5/2}_c(\mathbb R^3). \tag{7.6}

The smooth potentials of nuclei within any of the fixed local multiples of a_x used below sum to at most Ca_x^{-4}. Indeed each such width is comparable to a_x, each unit-mass smooth potential is at most C/a_x, and the total local charge is at most a_x^{-3}.

Let W_0,\rho_0 be the field and density for the original nuclear measure \nu. Its continuous offset is

h_0=W_0-V_c=V_s-K*\rho_0.

For a fixed positive \theta, to be chosen below, let W_s be the field for the smooth source \theta\nu_s.

Lemma 7.3 (Two reference fields). There are fixed constants c_0>0, \theta>0, c_\theta>0, and C<\infty such that, off the nuclei,

W_0(x)\ge c_0a_x^{-4},\qquad |h_0(x)|\le Ca_x^{-4}, \tag{7.7}

and everywhere

c_\theta a_x^{-4}\le W_s(x)\le Ca_x^{-4},\qquad |\nabla W_s(x)|\le Ca_x^{-5},\qquad W_s(x)\le1.01W_0(x). \tag{7.8}

Here h_0 is continuous, and W_s is locally C^1. Both fields decay at infinity.

Proof. By the scale definition, \nu(B(x,2La_x))>(2a_x)^{-3}. Truncate charges in this ball to total q=(2a_x)^{-3} and apply Lemma 7.2. Their distances from x are at most 2La_x, so (7.2) gives the first bound in (7.7) with a fixed c_0>0.

If some charges contribute to V_c(x), denote their total by q\le a_x^{-3}. The screening estimate for each single field of charge q, followed by the mixture comparison, gives

W_0(x)\ge\sum_{\rm contributors}\frac{z_m}{|x-R_m|}-Cq^{4/3} \ge V_c(x)-Ca_x^{-4}.

If there are no contributors, the same conclusion follows from W_0\ge0.

For the upper bound, set a=a_x, s=4a, and let V_{\rm loc} be the potential of nuclei within 20a of x. On B(x,s) the function

V_{\rm loc}(z)+\frac{C s^4}{(s^2-|z-x|^2)^4}

is a supersolution of the field equation when C is large: the Laplacian of the second term is at most 80Cs^6/(s^2-|z-x|^2)^6, whereas its pth power has the same spatial dependence and coefficient C^{3/2}. The boundary blowup dominates W_0-V_{\rm loc}. The positive-difference test is legitimate because the point singularities cancel. Thus W_0(x)\le V_{\rm loc}(x)+Ca^{-4}. Subtracting V_c(x) and using the smooth local potential bound proves the upper offset estimate. The expression defining h_0 proves its continuity.

For W_s, the same bump without V_{\rm loc} is a supersolution after its coefficient is enlarged to absorb the locally bounded source 4\pi\theta\nu_s. This proves W_s\le Ca^{-4}. Its Laplacian is bounded by Ca^{-6} on a local ball. Subtract the Newton potential of this source restricted to that ball. Its gradient is bounded by Ca^{-5}, since the integral of |z|^{-2} on a ball of radius a is Ca. The remaining harmonic function is bounded by Ca^{-4} on a smaller ball; its interior gradient bound proves the stated estimate and local C^1 regularity.

For the lower bound, select and truncate the same charges as in the first paragraph, before multiplying them by \theta. Their smearing widths are at most 3c_1a, because their centers are within 2La. A single such blob of charge \theta(2a)^{-3} has bare potential at x at least c_L\theta a^{-4}: every source point is within (2L+3c_1)a of x. Its screening potential is at most C\theta^{4/3}a^{-4}. Choose \theta sufficiently small and apply the mixture comparison to obtain W_s\ge c_\theta a^{-4}.

Decrease \theta further if necessary. The source bound and the lower bound for W_0 imply

4\pi\theta\nu_s \le \cF\bigl(1.01^{3/2}-1.01\bigr)W_0^{3/2}.

Consequently 1.01W_0 is a supersolution for the field of \theta\nu_s; its extra negative point sources have the required sign. The positive-difference test for W_s-1.01W_0, supported away from those point singularities, proves the final comparison. Decay follows from Lemma 7.1.

The reference fields now have positive lower bounds at every scale. To compare them with the local quantum constructions, we also need to control variation over a much smaller ball. The offset is the right quantity for this purpose: subtracting V_c removes every nuclear singularity from the function being compared.

Lemma 7.4 (Oscillation of offsets). Fix y and write a=a_y. Let h=h_0, or let h=W-V_c for an interior Thomas–Fermi patch centered at y satisfying the hypotheses of Lemma 4.3. Then h has a continuous representative. For 0<s\le a/10 and |z-y|\le s,

|h(z)-h(y)|\le Ca^{-4}(s/a)^{1/2}+C(s/a)h(y)_-. \tag{7.9}

For h=h_0 the final term can be omitted.

Proof. In either case the local upper field estimate in (4.23) or Lemma 7.3 gives h\le Ca^{-4} on a fixed ball about y. The patch core is absent there. The Euler equation, the bound on \nu_s, and the weighted power inequality give

|\Delta h(z)|\le Ca^{-6} +Ca^{-3/2}\sum_{\rm loc}z_m|z-R_m|^{-3/2}. \tag{7.10}

Here all centers in the sum belong to one fixed local ball and their total charge is at most a^{-3}. The same estimate holds for h_0 by Lemma 7.3.

Take the Newton particular solution for this Laplacian restricted to a ball of radius a. Equation (7.4) bounds it by Ca^{-4} on a smaller ball. Its variation over distance s is at most Ca^{-4}(s/a)^{1/2}. In detail, the part within distance Cs of either evaluation point is at most

C\bigl(a^{-6}s^2+a^{-9/2}s^{1/2}\bigr).

On a dyadic ring of radius l\ge Cs, the difference of the two Coulomb kernels is at most Cs/l^2, and the source mass in that ring is at most C(a^{-6}l^3+a^{-9/2}l^{3/2}). Summing the rings up to radius a gives the asserted variation.

The harmonic remainder is bounded above by Ca^{-4}. Harnack’s inequality and the harmonic gradient estimate, applied to this upper constant minus the remainder, bound its variation by C(s/a)(a^{-4}+h(y)_-). Combining the estimates gives (7.9), as well as continuity. For h_0, Lemma 7.3 bounds its negative part by Ca^{-4}, which is absorbed by the first term.

7.3 Averaging at a smaller radius

Fix w=10^{-5}, and use the small parameter r_* fixed above. Define the smearing widths, center kernels, and averaging operator by

t_z=c_1a_z\min(a_z,r_*)^w,\qquad \mathcal K_z(y)=g_{t_z}^2(y-z),\qquad Rf(y)=\int\mathcal K_z(y)f(z)\,dz, \qquad \tau_y=t_y/a_y. \tag{7.11}

Thus R smooths a mass at its own center-dependent width. It preserves total mass, although it need not preserve the constant function exactly.

Lemma 7.5 (Kernel and potential estimates). Uniformly as r_*\downarrow0, a center contributing to Rf(y) satisfies |z-y|\le2t_y and t_z/t_y=1+O(r_*^w). Moreover,

R1(y)=1+O(r_*^w),\qquad \|\nabla_z\mathcal K_z(y)\|_\infty\le Ct_y^{-4},\qquad \|\nabla_z\mathcal K_z(y)\|_2\le Ct_y^{-5/2}. \tag{7.12}

The norms in these gradient estimates are taken in the center variable z. The operator R is bounded on L^{5/3} and preserves integrals. The correction

q_0=K*(\rho_0-R\rho_0) \tag{7.13}

is nonnegative, continuous, belongs to \dot H^1, and tends to zero at infinity. It satisfies

0\le q_0(y)\le Ca_y^{-4}\tau_y^{1/2}. \tag{7.14}

Proof. The scale function is 1/L-Lipschitz. The function a\mapsto c_1a\min(a,r_*)^w has Lipschitz constant O(r_*^w). Thus |t_z-t_y|\le O(r_*^w)|z-y|. If |z-y|\le t_z, this proves the support and comparability assertions. Replacing t_z by t_y changes the kernel by at most Cr_*^wt_y^{-3} on a ball of radius 2t_y, giving the first assertion of (7.12). The chain rule for a Lipschitz width gives the gradient bounds, first pointwise almost everywhere and then in L^2 by the support bound. Since \int\mathcal K_z(y)\,dy=1, Fubini proves preservation of integrals. Weighted Jensen followed by Fubini, using the bound on R1, proves the L^{5/3} estimate.

Newton’s theorem gives the nonnegative representation

q_0(y)=\int\rho_0(z) \bigl[K(y-z)-(K*g_{t_z}^2)(y-z)\bigr]\,dz.

Only |z-y|\le2t_y contributes. The local field bound gives

\rho_0(z)\le Ca_y^{-6} +Ca_y^{-3/2}\sum_{\rm loc}z_m|z-R_m|^{-3/2}.

Equation (7.4) therefore bounds the displayed integral by C(a_y^{-6}t_y^2+a_y^{-9/2}t_y^{1/2}), proving (7.14). Both \rho_0 and R\rho_0 belong to L^1\cap L^{5/3}, hence also to L^{6/5}. Their potentials are continuous and decay by the proof of Lemma 7.1; the Sobolev inequality and the Coulomb energy identity put their difference in \dot H^1.

Define the nonlinearity acting on an offset h\in\mathbb R by

f_y(h)=\cF\int\mathcal K_z(y)(V_c(z)+h)_+^p\,dz. \tag{7.15}

For each y, this is finite, convex, continuous, and nondecreasing in h. These properties follow from those of the positive power and the local integrability of V_c^p. We will use this averaged law in place of the unsmeared Thomas–Fermi equation.

7.4 Barriers with a strict gap between scales

We have established the reference fields and the averaging estimates. The remaining task is to lower the reference field just enough that its averaged density pays for the Laplacian of the lowering term. The strict inequality between the coefficients below leaves room for all errors from averaging.

Lemma 7.6 (Comparison barriers). There are fixed positive constants \alpha,\epsilon_0,C'_0,c_b,c' with the following properties for all sufficiently small r_*>0. For 0<r\le r_* define

\Gamma_r=\epsilon_0W_s+C'_0r^{4\alpha}W_s^{1+\alpha},\qquad B_r=W_0+q_0-\Gamma_r,\qquad b_r=B_r-V_c, \qquad h_b=h_0-c_ba^{-4}. \tag{7.16}

The offsets b_r are continuous and locally H^1 and decay at infinity. On \{a\ge r\} their Laplacian densities satisfy

\Delta b_r\ge-4\pi\nu_s+f_y(b_r). \tag{7.17}

More precisely, this inequality holds almost everywhere there between the locally integrable densities representing the two sides; on every open set contained in this region it is also a distributional inequality. On the same region,

B_r\ge0.9W_0>0,\qquad h_b+c'a^{-4}\le b_r\le Ca^{-4}. \tag{7.18}

For every contributing center z in (7.15),

V_c(z)+h_b(y)\ge ca_y^{-4} \quad\text{almost everywhere in }z. \tag{7.19}

All these constants are independent of r,r_* and the nuclear system.

Proof. First fix \theta as in Lemma 7.3. That lemma implies

D_*:=\sup_x\frac{|\nabla W_s(x)|^2}{W_s(x)^{5/2}}<\infty

with a fixed universal bound. Since \Delta W_s\le \cF W_s^{3/2}, the chain rule gives

\Delta(W_s^{1+\alpha}) \le(1+\alpha)(\cF+\alpha D_*)W_s^{\alpha+3/2}.

Choose \alpha>0 so small that (1+\alpha)(1+\alpha D_*/\cF)\le1.1. Consequently

\Delta\Gamma_r\le1.1\cF\sqrt{W_s}\,\Gamma_r. \tag{7.20}

All chain rules are local: W_s is positive and locally C^1 with locally bounded Laplacian, so multiplication in the weak equation justifies them.

Choose c_b>0 smaller than a sufficiently small fixed fraction of c_0. On a\ge r, r^{4\alpha}W_s^\alpha\le C^\alpha. We may therefore choose positive \epsilon_0,C'_0 so small that, throughout this region, \Gamma_r is a tiny fixed fraction of W_s, is at most 0.1c_0a^{-4}, and is at most (c_b/2)a^{-4}. At the same time,

\Gamma_r\ge\epsilon_0c_\theta a^{-4}. \tag{7.21}

These choices precede every smallness requirement on r_*.

The equations for h_0 and q_0 give the exact cancellation

\Delta(h_0+q_0)=-4\pi\nu_s+\cF R(W_0^p). \tag{7.22}

Fix y with a_y\ge r. For a contributing center z, the offset oscillation estimate and (7.14) imply

\begin{align*} V_c(z)+b_r(y) &=W_0(z)+h_0(y)-h_0(z)+q_0(y)-\Gamma_r(y)\\ &\le W_0(z)-\Gamma_r(y)+Ca_y^{-4}\tau_y^{1/2}.\end{align*}

By (7.21), the final error is o(\Gamma_r(y)) uniformly as r_*\to0. Furthermore,

W_0(z)\ge\frac{W_s(z)}{1.01} \ge\frac{1-o(1)}{1.01}W_s(y),

using the gradient and lower bounds for W_s and |z-y|\le2t_y. The chosen small ratio \Gamma_r/W_s and the derivative of the power therefore give

W_0(z)^p-(V_c(z)+b_r(y))_+^p \ge 1.35\sqrt{W_s(y)}\,\Gamma_r(y)

for sufficiently small damping fractions and then sufficiently small r_*. Indeed the limiting coefficient is p/\sqrt{1.01}>1.49. After integration in z, the factor R1(y)=1+o(1) leaves the lower bound 1.3\sqrt{W_s(y)}\Gamma_r(y). Combine this with (7.22) and (7.20) to prove (7.17). All terms represent locally integrable densities, so the assertion includes points of a level set of a up to a Lebesgue-null set; no regularity of those level sets is required.

Because q_0\ge0 and \Gamma_r\le0.1W_0, we have B_r\ge0.9W_0. The upper offset bound follows from b_r\le h_0+q_0. Also

b_r-h_b=q_0-\Gamma_r+c_ba^{-4}\ge(c_b/2)a^{-4},

so one may take c'=c_b/2. On the kernel support,

V_c(z)+h_b(y) =W_0(z)+h_0(y)-h_0(z)-c_ba_y^{-4} \ge ca_y^{-4},

by the lower bound for W_0, scale comparability, and the offset oscillation estimate, after decreasing r_* further. This proves (7.19).

Finally, h_0,q_0 are continuous and locally H^1, and the same is true of \Gamma_r. Their decay proves the remaining assertions.

Lemma 7.7 (Gap under doubling). Fix \kappa\in(0,1/10). The barriers in Lemma 7.6 have a fixed constant \gamma>0 such that, whenever R_+=2r\le r_*,

b_r-b_{R_+}\ge\gamma R_+^{-4} \qquad\text{on }\{R_+\le a\le(1+\kappa)R_+\}. \tag{7.23}

Proof. The difference is exactly

b_r-b_{R_+} =C'_0(1-2^{-4\alpha})R_+^{4\alpha}W_s^{1+\alpha}.

The lower bound for W_s gives the assertion with

\gamma=C'_0(1-2^{-4\alpha}) c_\theta^{1+\alpha}(1+\kappa)^{-4(1+\alpha)}>0.

The lower margin in (7.19) also controls inversion of the averaged law. If \delta_0>0 is a sufficiently small fixed constant, differentiation under the integral gives

\frac{d}{dh}\frac{f_y(h)}{4\pi}\ge ca_y^{-2} \qquad\text{for }h\ge h_b(y)-\delta_0a_y^{-4}. \tag{7.24}

Indeed (V_c(z)+h)_+^{p-1}\ge ca_y^{-2} on the kernel support, and R1(y) is bounded below. This derivative bound and the gap (7.23) are the two margins used in the conditional field comparisons and the subsequent passage from r to 2r.

8 Noisy observations and conditional screening

We compare the conditional electron density with the nonlinear reaction law of Section 7. The observation noise makes a rare data event inexpensive to impose on the eigenstate. A local quantum comparison in the resulting state will then rule out each failure of the desired inverse relation. We use the master kernels and deterministic barriers of Section 7, with the small parameter now chosen from the proposed excess charge.

Suppose, towards a contradiction, that the asserted uniform excess-charge bound fails. By Lemma 2.3, choose systems at their largest strictly bound sectors such that

K_{\rm exc}:=N-Z>0,\qquad K_{\rm exc}/M\longrightarrow\infty.

Fix a universal constant B_0>2, to be enlarged in the final argument, and define

r_*=(B_0M/K_{\rm exc})^{1/3}\longrightarrow0,\qquad r_0=2^{-n}r_*,\qquad r_j=2^jr_0\quad(0\le j\le n), \tag{8.1}

where the finite integer n\ge1 is chosen so that r_0<Z^{-1/3}. The crude bound N\le3Z and M\ge1 imply r_*>Z^{-1/3}. All subsequent smallness assertions concern this sequence of systems; their thresholds will be universal and independent of n.

8.1 The common observation construction in molecular geometry

Set \ell_j=r_j^{1.01} for j<n. Use the unordered arrays and likelihood versions of Section 5, with N particles, indices j,\ldots,n-1, and \mathcal F_n trivial. The master kernels are those of (7.11). Define

\mu_j(y)=\E\left[\sum_{i=1}^N\mathcal K_{x_i}(y)\mid\mathcal F_j\right], \qquad H_j=V_s-K*\mu_j.

Lemma 5.1 gives the joint versions, fixed-system regularity, Poisson equation, and the tower property. Here the ground state attains E, so Lemma 5.2 gives offset C\ell_j^{-2}\log^5(e/P_A) for every event of probability P_A>0.

8.2 Upper tails and a spatial cap

The observations have two uses. First, their conditional electron density is a continuous field to which elliptic comparisons apply. Second, an event of these observations can be imposed at the small energy cost in Lemma 5.2. We first use that cost to exclude large positive fields and excessive local observed counts.

For this subsection fix a numerical constant L_1\ge1. Its value will be chosen after the universal field caps have been obtained. At scale r=r_j, put R_+=2r. Constants in estimates of small probabilities may depend on L_1; the field thresholds below do not.

Lemma 8.1 (Positive conditional-field tail). If r/2\le a_y\le5L_1r, then, for a universal C and every s>C,

\Prob\{H_j(y)>s a_y^{-4}\} \le e\exp\{-c_{L_1}(s-C)^{2/5}a_y^{-1+.004}\}. \tag{8.2}

All estimates hold for sufficiently small r_*, uniformly in j<n.

Proof. Write a=a_y and tilt the event in question, if it has positive probability P_A. By the tower property, its average of K*\mu_j is the tilted raw average of the potential of the master smears. Nuclei within a fixed multiple of a contribute at most Ca^{-4} to V_s. More distant electron smears have exactly their bare potential at y: a contributing smear near y has center within 2t_y\ll a. Dropping the remaining negative electron terms therefore gives

\E[H_j(y)\mid A]\le Ca^{-4}+\E_{\psi_A}J_y.

Lemmas 4.2 and 4.4, with no initial cut, bound the last expression by Ca^{-4}+C\sqrt{\delta/a}. Indeed, for small a, their scale quantity is bounded by C(a^{-7}+\delta). Lemma 5.2 and \ell_j\ge c_{L_1}a^{1+.01} imply

s-C\le C a^{7/2}\ell_j^{-1}\log^{5/2}(e/P_A) \le C_{L_1}a^{2.49}\log^{5/2}(e/P_A).

Solving for P_A proves the assertion. The deterministic threshold comes solely from the universal local field estimates.

Call \{r\le a\le2L_1R_+\} the participating band. Use a grid of closed cubes Q of side r/100 meeting this band. Let Q' be concentric enlargements, chosen with bounded overlap to contain every ball of radius r centered in Q, with an additional margin. The Lipschitz bound for a ensures that a_Q:=\inf_{Q'}a\ge r/2 and that all points in Q' fall in the range of Lemma 8.1. Choose smooth 0\le\chi_Q\le1 equal to one on Q, supported in Q', with |\Delta\chi_Q|\le Cr^{-2}.

Lemma 8.2 (Spatial cap and its exceptional cost). There are universal thresholds C'_{\rm cap},C_{\rm cap} with the following properties. Define

\begin{split} Q\text{ is bad}&\quad\Longleftrightarrow\quad \sup_QH_j>C'_{\rm cap}a_Q^{-4},\\ B_Q&=\1_{\{Q\text{ bad}\}}\sup_Q(H_j)_+, \qquad \Pi=\sum_QB_Q\chi_Q,\qquad \mathcal E=\bigcup_{Q\text{ bad}}Q'. \end{split}

Then H_j-\Pi\le C_{\rm cap}a^{-4} on the participating band. For each fixed m\ge1 and A'>0,

\Prob(Q\text{ bad})+a_Q^{4m}\E B_Q^m \le C_{L_1,m,A'}r^{A'}. \tag{8.3}

At each deterministic point, \Prob(y\in\mathcal E) has the same arbitrarily high polynomial bound. The cube families are finite, and

\sum_Q|Q'|\le C_{L_1}Mr^3. \tag{8.4}

All these random objects are jointly measurable in the data and the spatial variable. For the fixed system and scale, their sizes and supports have deterministic bounds.

Proof. Since \Delta H_j\ge-Ca_Q^{-6} on Q', adding a quadratic and applying the ball submean inequality gives, for any fixed large C' and a universal C'',

\sup_QH_j\le C''a_Q^{-4} +Cr^{-3}\int_{Q'}(H_j-C'a_Q^{-4})_+.

The same inequality follows for distributional Laplacians by mollification. Choose C' above the threshold in Lemma 8.1. Because a_z/a_Q is bounded and a_z\le5L_1r on Q', integration of that tail yields

\E(H_j(z)-C'a_Q^{-4})_+^m \le C a_Q^{-4m}r^{A'}

for arbitrary fixed m,A'. Jensen’s inequality for the spatial average gives the same bound for the integral term. Taking C'_{\rm cap}>C''+1, Markov’s inequality gives the bad-cube probability. On a bad cube its supremum is bounded by the integral term plus C''a_Q^{-4}; the probability just proved controls the latter contribution to every moment. This proves (8.3).

If a point lies in a bad cube, the corresponding term of \Pi dominates (H_j)_+ there. Otherwise the good-cube bound gives the asserted cap, since a_Q and the local scale are comparable by a universal factor. At a fixed point only a bounded number of enlarged cubes occur, proving the estimate for \mathcal E. Every participating or enlarged cube lies within distance C_{L_1}r of some nucleus, by d_y\le La_y. Counting grid cubes in this union proves finiteness and (8.4). Cube suprema are measurable through a countable dense subset, because H_j is continuous. The bounds from Lemma 5.1 also give the last assertion.

8.3 The inverse comparison and the order of constants

We now fix the constants needed for propagation. Choose C_{\rm inv} larger than the barrier upper bound in a^{-4} units and than C_{\rm cap}. Choose C_{\rm top}>C_{\rm inv} sufficiently large and put h_{\rm top}(y)=C_{\rm top}a_y^{-4}; this also exceeds h_b with a fixed margin. If \gamma is the constant in Lemma 7.7, choose 0<\lambda_2<\lambda_1<\gamma/4. Choose L_1 sufficiently large that, when a>L_1R_+, subtracting \lambda_2R_+^{-4} from either upper cap places it strictly below b_{R_+}. This is possible since |b_{R_+}|\le Ca^{-4} there. The preceding probability estimates now apply with this fixed L_1.

Choose a safety constant e_0>0 so small that \eta=e_0R_+^{-4} is smaller than the barrier margin above h_b throughout R_+\le a\le2L_1R_+ and than the shift gap. Finally choose \delta_0>0 small compared with that margin, \lambda_2, and \lambda_1-\lambda_2, so that

16\delta_0+2e_0<\lambda_1-\lambda_2,\qquad \delta_0<\lambda_2,\qquad 2e_0<c'(2L_1)^{-4}. \tag{8.5}

These choices precede the final smallness requirement on r_*.

Define

T_y(h)=\frac{f_y(h)}{4\pi},\qquad I_y(m)=\begin{cases} h_b(y),&m\le T_y(h_b(y)),\\ T_y^{-1}(m),&T_y(h_b(y))<m<T_y(h_{\rm top}(y)),\\ h_{\rm top}(y),&m\ge T_y(h_{\rm top}(y)). \end{cases}

The positivity on the master kernel established with the barriers implies

T_y'(h)\ge ca_y^{-2} \quad(h\ge h_b(y)-\delta_0a_y^{-4}). \tag{8.6}

Indeed, differentiating the power 3/2 leaves a positive square root bounded below by ca_y^{-2} on a kernel of integral 1+o(1). Thus the inverse on the indicated interval exists and is continuous. The clipped inverse satisfies

\begin{aligned} m\ge T_y(h_b)&\ \Longrightarrow\ T_y(I_y(m))\le m,\\ m\le T_y(h_{\rm top})&\ \Longrightarrow\ T_y(I_y(m))\ge m. \end{aligned} \tag{8.7}

Lemma 8.3 (One-sided inverse comparisons). Fix j<n, and put r=r_j and R_+=2r. For each deterministic y with r\le a_y\le2L_1R_+, the failure probability of each implication below is less than r^{40}:

\begin{aligned} \mu_j(y)\ge T_y(h_b(y)) &\ \Longrightarrow\ H_j(y)\ge I_y(\mu_j(y))-\delta_0a_y^{-4},\\ \mu_j(y)\le T_y(h_{\rm top}(y)) &\ \Longrightarrow\ H_j(y)\le I_y(\mu_j(y))+\delta_0a_y^{-4}. \end{aligned} \tag{8.8}

The constants and the smallness threshold for r_* are independent of the system and the number of scales.

Proof. The argument has three steps. Observation matching first relates the conditional density to the particles retained by a fresh patch. The patch comparison then determines the local offset except for a small event, whose negative-field cost must also be controlled. Finally, two separate tower identities transfer the offset comparison back to the master field.

A count-good event and the fresh patch. Write a=a_y, t=t_y, \tau=t/a. Recall that Rf(y)=\int\mathcal K_z(y)f(z)\,dz: the averaging and the kernel gradient estimates below concern the center variable z. There is a universal K_0 such that

\Prob\{\#\{i:Y_{ji}\in B(y,3a)\}>K_0a^{-3}\}<r^{42}. \tag{8.9}

Otherwise tilt this event. Lemma 5.2 gives \delta\le Cr^{-2.02}\log^5(e/r^{42})\le a^{-7+.02} for small r_*. The last inequality is uniform: after multiplication by a^{6.98} its left side is at most C_{L_1}r^{4.96}\log^5(e/r^{42}). Every compatible raw configuration has the same excessive count in B(y,4a), because \sqrt3\ell_j=o(a). A fixed cell cover and Lemma 4.4 contradict this for large enough K_0.

Call the complement of this excessive-count event count-good. On such an observation path, match its entries to any compatible raw configuration. The kernel Lipschitz bound gives

\left|\sum_i\mathcal K_{x_i}(y) -\sum_i\mathcal K_{Y_{ji}}(y)\right| \le Ca^{-3}\ell_jt^{-4}. \tag{8.10}

Only observations in B(y,3a) can contribute to this difference. The conditional ratios in Lemma 5.1 are supported on compatible configurations. Averaging (8.10) therefore gives the same bound with \mu_j(y) replacing the raw sum.

If an implication in (8.8) fails with probability at least r^{40}, intersect its failure event with count-good data and call the result A. Then P_A:=\Prob(A)\ge r^{41} for small r. Write P for the original joint law of raw variables and all noisy arrays, and Q=P(\cdot\mid A). Its raw marginal is the law of \psi_A=\sqrt{p_A/P_A}\Psi, with \delta\le a^{-7+.02}. Apply Lemma 4.3 to this state, choosing b=a^{1+.2} and \beta=b/a=a^{.2}. Once selected by shell averaging, the patch radius is deterministic. Extend Q by sampling the fresh cut labels conditionally on the raw variables with the cut’s squared partition probabilities. The raw-label marginal is exactly the patch construction for \psi_A. Write X for its cut data, \rho_X^c for its conditional core density, \rho for its local Thomas–Fermi minimizer, and \sigma for its retained fine density. These are conditional objects under this tilted patch law. In contrast, \mu_j remains the conditional density defined under P.

LawConstruction and conditional quantities
P=\ProbThe raw state \Psi with independent noisy arrays. The fields \mu_j,H_j retain their definitions using \mathcal F_j under this law.
QP(\cdot\mid A), extended by the fresh cut labels. The quantities \rho_X^c,\rho,\sigma use its raw-label marginal and the cut data X.

The fine smearing moves retained centers by at most \sqrt3b. Every particle relevant to the master kernel is in the retained central region. Thus (8.10) implies, Q-almost surely,

|R\sigma(y)-\mu_j(y)|\le Ca^{-3}(\ell_j+b)t^{-4}=o(a^{-6}). \tag{8.11}

Let G=\{D(\sigma-\rho)\le a^{-7+.01}\}. Lemma 4.6 gives

\E_Q\left[D(\sigma-\rho)+\int W_-\sigma\right] \le Ca^{-7+.02},\qquad \E_Q\int\sigma^{5/3}\le Ca^{-7}. \tag{8.12}

In particular Q(G^c)\le Ca^{.01}. On G, Lemma 3.1 gives

|R\rho(y)-R\sigma(y)|\le Ct^{-5/2}a^{-3.5+.005}=o(a^{-6}).

For clarity, after division by a^{-6} these two errors are bounded by

C\{a^{.01}\tau^{-4}+a^{.2}\tau^{-4} +a^{.005}\tau^{-5/2}\}=o(1). \tag{8.13}

The lower bound \tau\ge c_{L_1}a^w, w=10^{-5}, makes every power positive.

The local inverse comparison and rare negative fields. Put h_X=W-V_c. On G, in the high-density case one must have

h_X(y)\ge I_y(\mu_j(y))-\tfrac14\delta_0a^{-4}. \tag{8.14}

Indeed, the opposite inequality and Lemma 7.4 imply on the master kernel h_X(z)\le I_y(\mu_j(y))-\delta_0a^{-4}/8. To cover arbitrarily negative h_X(y), note that h\mapsto h+C\tau h_- is increasing for small \tau; evaluate it at the proposed upper threshold, which is bounded in a^{-4} units. The oscillation error there is o(a^{-4}). The Thomas–Fermi equation, (8.6), and the first part of (8.7) then yield R\rho(y)\le\mu_j(y)-c\delta_0a^{-6}, contradicting (8.13). In the low-density case the lower oscillation estimate and the increasing function h\mapsto h-C\tau h_- similarly give, on G,

h_X(y)\le I_y(\mu_j(y))+\tfrac14\delta_0a^{-4}. \tag{8.15}

Here the second clipping inequality is used.

The deterministic upper bound h_X(y)\le Ca^{-4} controls the positive error on G^c in the low-density case. The high-density case requires a bound on negative fields there. By kernel positivity, \mu_j\ge T_y(h_b)\ge ca^{-6}. Equation (8.11) and \mathcal K_z(y)\le Ct^{-3} force, on every configuration,

m_\sigma:=\int_{B(y,2t)}\sigma\ge ca^{-6}t^3=ca^{-3}\tau^3.

The upper oscillation bound implies on this ball

W_-\ge(1-C\tau)h_X(y)_--V_c-Ca^{-4}\tau^{1/2}.

Integrate against \sigma, divide by m_\sigma, and average over G^c. The patch bound controls the W_-\sigma numerator by Ca^{-7+.02}. For the nuclear term, weighted convexity and the uniform integral of |z-R_m|^{-5/2} on a radius-2t ball give

\int_{B(y,2t)}V_c^{5/2}\le Ca^{-7}\tau^{1/2}.

Hölder’s inequality on probability times space therefore gives

\begin{split} \E_Q\1_{G^c}\int_{B(y,2t)}V_c\sigma &\le\left(\E_Q\int\sigma^{5/3}\right)^{3/5} \left(Q(G^c)\int_{B(y,2t)}V_c^{5/2}\right)^{2/5}\\ &\le Ca^{-7+.004}\tau^{.2}. \end{split}

We conclude that

\E_Q\1_{G^c}h_X(y)_- \le Ca^{-4}\{a^{.02}\tau^{-3}+a^{.004}\tau^{-2.8} +Q(G^c)\tau^{1/2}\}=o(a^{-4}). \tag{8.16}

Since |I_y|\le Ca^{-4}, the bounds on G now imply the corresponding one-sided comparisons in expectation, with error \delta_0a^{-4}/4+o(a^{-4}).

Transfer of averaged fields. The remaining step compares the expectation of this fresh patch offset with that of the master offset under the event law Q. Apply Lemma 5.3 with the nuclear splitting V=V_s+V_c, master width t=t_y, and fine width b=a^{1.2}. Lemma 4.6 gives the raw local density and Coulomb error bounds; the deleted shell estimate is (4.26). The pointwise density bound required for the nuclear remainder follows from \rho=kW_+^{3/2} and (4.23); its potential on a radius-t ball is Ca^{-4}(t/a)^{1/2} by (7.4). Thus the explicit transfer estimate is

|\E_Q(H_j-h_X)(y)| \le Ca^{-4}\{\tau^{1/5}+\beta^{1/5}+\beta^{1/2} +a^{.01}\tau^{-1/2}+\tau^{1/2}\}=o(a^{-4}). \tag{8.17}

Here \beta=a^{.2}, c_{L_1}a^w\le\tau\le c_1r_*^w, and .01-w/2>0. The two expectations in the common lemma use different conditional laws; this verification identifies neither posterior pathwise.

On the high failure event, every path has H_j(y)<I_y(\mu_j(y))-\delta_0a^{-4}. Equations (8.14) and (8.16), together with (8.17), instead give

\E_QH_j(y)\ge\E_QI_y(\mu_j(y)) -\tfrac14\delta_0a^{-4}-o(a^{-4}),

a contradiction. The low failure event is contradicted in the same way by (8.15), the deterministic upper bound on h_X, and (8.17). All remainders are uniform: a\asymp_{L_1}r, \tau\ge c_{L_1}a^w, and the smallest power in (8.16) is .004-2.8w>0. The constants were fixed before letting r_*\to0.

8.4 Moments for the integrated exceptional cost

The inverse estimates concern each deterministic spatial point. Their use in the next section requires integrable costs for failed comparisons, not a single event on which all points succeed.

Lemma 8.4 (Conditional-density and reaction moments). Fix j<n, put r=r_j and R_+=2r, and let r\le a_y\le2L_1R_+. Under the original joint law P=\Prob,

\|\mu_j(y)\|_2\le Ct_y^{-3}a_y^{-3},\qquad \|f_y(H_j(y))\|_2 \le Ca_y^{-6}(1+\tau_y^{-3/2}). \tag{8.18}

Consequently, if F_y is either failure event from Lemma 8.3, then

\int_{\{r\le a_y\le2L_1R_+\}} \E\big[\1_{F_y}(\mu_j(y)+f_y(H_j(y)))\big]\dd y \le CM r^{20-3-3w}. \tag{8.19}

The same bound holds with F_y replaced by \{y\in\mathcal E\}, and the expected integral over all of \R^3 of r^{-2}\sum_QB_Q\1_{Q'} is bounded by the right side as well.

Proof. Conditional Jensen, the master-kernel support, and Lemma 4.4 give

\|\mu_j(y)\|_2\le Ct_y^{-3} \|\#\{i:x_i\in B(y,a_y)\}\|_2 \le Ct_y^{-3}a_y^{-3}.

The tail bound implies \|(H_j(y)_+)^{3/2}\|_2\le Ca_y^{-6}. For the nuclear part of the reaction, weighted convexity and the uniform integral of |z-R_m|^{-3/2} on a radius-2t_y ball give

\int\mathcal K_z(y)V_c(z)^{3/2}\dd z \le Ct_y^{-3}a_y^{-9/2}t_y^{3/2} =Ca_y^{-6}\tau_y^{-3/2}.

This proves (8.18). Cauchy–Schwarz against \Prob(F_y)<r^{40} contributes r^{20}. Use a_y\asymp_{L_1}r, \tau_y\ge c_{L_1}r^w, and (8.4) to obtain (8.19). The arbitrarily high polynomial bounds in Lemma 8.2 give the other assertions, choosing their exponent larger if necessary. All integrations are licensed by the joint measurable versions already constructed.

9 Outward propagation and the excess-charge bound

The inverse comparisons now allow us to replace a reaction term by the conditional electron density on one more layer of local scales. We perform this replacement before forgetting the observations at the current scale. The failed comparisons contribute a nonnegative error density. Its expected integral, rather than the probability of a simultaneous comparison throughout space, is the quantity that we shall sum.

We use the scales r_j=2^j r_0, r_n=r_* and the retained data \mathcal F_j of Section 8. The data \mathcal F_n are trivial. Write \mu_j for their conditional smoothed density. At each step we take a local maximum of the previous comparison field and the observed field H_j, after lowering them by different constants. The previous field supplies the nonlinear reaction; H_j supplies the actual density through its Poisson equation. The unequal shifts let the inverse comparisons prove the missing source inequality for each branch that can attain the maximum.

After the last observations are forgotten, the resulting positive exterior field will bound the smoothed electron mass in \{a<r_*\} by Z plus the accumulated error. The exterior-count estimate of Lemma 6.2 controls the remaining smoothed mass, while the error has integral o(M). These are the two contributions to the final excess-charge estimate.

The invariant at scale r=r_j is a continuous locally H^1 offset u and a nonnegative bounded compactly supported error density d_j such that

\Delta u\ge -4\pi\nu_s +4\pi\1_{\{a<r\}}\mu_j-4\pi d_j +\1_{\{a\ge r\}}f_y(u) \quad\text{in distributions}, \tag{9.1}

and

b_r\le u\le C_{\mathrm{inv}}a^{-4}\quad\text{on }\{a\ge r\}, \qquad u=b_r\quad\text{on }\{a>L_1r\}. \tag{9.2}

Here and below an inequality between spatial functions is asserted for every positive-density retained path, using the versions of Lemma 5.1. The functions u,d_j are jointly measurable in the retained data and space. We also maintain deterministic bounds, for the fixed physical system and step, on the modulus of continuity and the H^1 norm of u on every compact set, and on the size and support of d_j. These additional bounds justify conditional integration. The integral estimate for d_j will instead have universal constants.

9.1 Replacing one layer of reaction by density

For this subsection put r=r_j, R_+=2r, and H=H_j. All parameters are fixed in the order specified in Section 8. We record the inequalities that enter the argument:

\lambda_1<\frac\gamma4,\qquad 16\delta_0+2e_0<\lambda_1-\lambda_2,\qquad \delta_0<\lambda_2,\qquad 2e_0<c'(2L_1)^{-4}. \tag{9.3}

The constant c'>0 is the margin in b_r\ge h_b+c'a^{-4}. Set \eta=e_0R_+^{-4} and T_y=f_y/(4\pi).

For the current data, denote the high and low failure sets of Lemma 8.3 by

\begin{align*} \mathcal B^{\mathrm h} &=\{y:\mu_j(y)\ge T_y(h_b(y)),\quad H(y)<I_y(\mu_j(y))-\delta_0a_y^{-4}\},\\ \mathcal B^{\mathrm l} &=\{y:\mu_j(y)\le T_y(h_{\mathrm{top}}(y)),\quad H(y)>I_y(\mu_j(y))+\delta_0a_y^{-4}\}.\end{align*}

These sets are used only within the participating band r\le a\le2L_1R_+. Let \Pi, B_Q, Q' and \mathcal E be the penalty, its cube coefficients, the enlarged cubes and their bad union from Lemma 8.2. In particular \Pi=0 off \mathcal E and H-\Pi\le C_{\mathrm{cap}}a^{-4} throughout this band.

Proposition 9.1 (One outward step). Suppose that u,d_j satisfy the inductive conditions above, including (9.1)–(9.2), at scale r=r_j. There are an offset u' and a nonnegative error density \widetilde d, measurable with respect to the same data \mathcal F_j, that satisfy these inequalities at scale R_+ with \mu_j still in the core term. One may take

\begin{align*} \widetilde d={}&d_j+C r^{-2}\sum_Q B_Q\1_{Q'}\\ &+\1_{\{r\le a<R_+\}}\mu_j \1_{\mathcal E\cup\mathcal B^{\mathrm h}}\\ &+\1_{\{R_+\le a\le2L_1R_+\}}T_y(H) \1_{\mathcal E\cup\mathcal B^{\mathrm l}}, \tag{9.4}\end{align*}

where C is a universal constant large enough to dominate the penalty Laplacian.

Proof. Define two shifted offsets

u_1=u-\lambda_1R_+^{-4},\qquad u_2=H-\lambda_2R_+^{-4}-\Pi.

Use the following open cover to define u':

\begin{array}{c|c} \text{open region}&u'\\ \hline a<(1+\kappa)R_+&\max(u_1,u_2)\\ (1+\kappa/2)R_+<a<2L_1R_+&\max(u_1,u_2,b_{R_+})\\ a>L_1R_+&b_{R_+}. \end{array} \tag{9.5}

The definitions agree on overlaps. On the lower overlap, Lemma 7.7 and (9.3) give

u_1\ge b_r-\lambda_1R_+^{-4}>b_{R_+}.

On the upper overlap the shifted cap inequalities, ensured by the choice of L_1, put both u_1 and u_2 below b_{R_+}. Thus the local maxima glue to a continuous locally H^1 function. No assertion about the measure or regularity of a level set of a is required. The new exterior bounds follow from the same comparisons: for R_+\le a<(1+\kappa)R_+ the lower bound is supplied by u_1, and elsewhere the barrier is an included branch.

We verify the differential inequality locally. At a fixed point in one of the open regions, discard branches more than \eta below the maximum. There is a neighborhood on which these discarded branches cannot attain the maximum, while every retained branch is within 2\eta of it. We show that each retained branch satisfies the common inequality

\Delta v\ge -4\pi\nu_s+4\pi\1_{\{a<R_+\}}\mu_j -4\pi\widetilde d+\1_{\{a\ge R_+\}}f_y(v) \tag{9.6}

on that neighborhood.

For u_1, the old core inequality suffices on a<r, and monotonicity of f_y gives the required reaction on a\ge R_+. On the gain region r\le a<R_+, the error in () pays \mu_j at points of \mathcal E\cup\mathcal B^{\mathrm h}. At every other gain point, \Pi=0 and near activity yields

H\le u-(\lambda_1-\lambda_2)R_+^{-4}+2\eta.

Here h_b\le u\le h_{\mathrm{top}}. If \mu_j>T_y(u), then the high comparison applies and I_y(\mu_j)\ge u, including the case where the inverse is clipped at its upper endpoint. It would follow that

H\ge u-\delta_0a^{-4}\ge u-16\delta_0R_+^{-4},

contrary to (9.3). Thus 4\pi\mu_j\le f_y(u). The old reaction supplies precisely the new core term on the gain region.

For u_2, the identity \Delta H=-4\pi\nu_s+4\pi\mu_j gives the required core term on all of a<R_+, while the first increment in () pays the Laplacian of \Pi. Consider the remaining points where u_2 is retained. The lower splice or the included barrier gives

u_2\ge b_{R_+}-2\eta \ge h_b+c'a^{-4}-2e_0R_+^{-4}>h_b.

The last inequality uses a\le2L_1R_+ and (9.3). On \mathcal E\cup\mathcal B^{\mathrm l} the last error term pays the reaction because u_2\le H and f_y is nondecreasing. Otherwise \Pi=0 and the cap gives H<h_{\mathrm{top}}. If \mu_j<T_y(u_2), the low comparison applies and I_y(\mu_j)\le u_2, also when the inverse is clipped at its lower endpoint. We would obtain

H\le u_2+\delta_0a^{-4}\le u_2+\delta_0R_+^{-4},

contradicting H=u_2+\lambda_2R_+^{-4}. Therefore 4\pi\mu_j\ge f_y(u_2), as required.

The barrier branch appears only where a>R_+, and Lemma 7.6 gives (9.6) there. The old error density and every additional error are nonnegative, so they can only weaken the required lower bound.

These comparisons cover the exact level sets as well: a=r belongs to the gain region and uses the old reaction, whereas a=R_+ belongs to the new exterior and uses its reaction. All right-side comparisons hold almost everywhere on the chosen neighborhood and therefore upgrade each retained branch’s distributional inequality to (9.6). The source \nu_s is a smooth bounded density for the fixed system, and all branches here are continuous and locally H^1. The reaction is also bounded on bounded ranges of its argument: for a fixed system, t_{\min}:=\inf_z t_z>0 and V_c\in L_c^{5/2} give, for every A>0,

\sup_{y,\,|h|\le A} f_y(h) \le C t_{\min}^{-3}\int V_c^{3/2} +CA^{3/2}\sup_y R1(y)<\infty.

Thus the first, nonsingular part of Lemma 5.4, followed by a partition of unity, proves the inequality for u' on all of \R^3. No vanishing of the reaction near the original nuclei is needed in this step.

9.2 Averaging the data and summing the error

The next step explains why the nonlinear reaction survives the removal of observations. It also records the integrability needed in that operation.

Lemma 9.2 (Forgetting the current observations). Set

u_{j+1}=\E[u'\mid\mathcal F_{j+1}],\qquad d_{j+1}=\E[\widetilde d\mid\mathcal F_{j+1}].

Then u_{j+1},d_{j+1} satisfy (9.1)–(9.2) at scale r_{j+1}, with conditional density \mu_{j+1}. They retain continuity and local H^1 regularity for the offset and bounded compact support for the nonnegative error density.

Proof. For the fixed system there are finitely many scales and cubes, and all master smoothing widths have a positive minimum. Lemma 5.1 therefore gives deterministic bounds for the conditional densities, their potentials and their gradients. The offsets and error densities in the assertion are jointly measurable: maxima, clipped inverses and failure flags preserve measurability, and each cube supremum may be taken over a fixed countable dense subset.

Inductively the branches have deterministic continuity moduli and local H^1 bounds on each compact set. Their open definitions agree on overlaps; a finite subcover of a compact set supplies a Lebesgue number and hence a modulus for the glued function. The gradient of a finite maximum is almost everywhere one of the branch gradients. Conditional averaging consequently preserves continuity. It preserves the local H^1 bound by testing weak derivatives against compactly supported vector fields, using Fubini and Cauchy–Schwarz. The error terms have deterministic bounded size and support for the fixed system and step, so the same is true after averaging.

Integrate the distributional inequality of Proposition 9.1 against a fixed nonnegative compact test and then against the explicit positive-parent conditional law of Lemma 5.1. The preceding bounds justify Fubini. The tower property gives \E[\mu_j\mid\mathcal F_{j+1}]=\mu_{j+1}, while convexity gives

\E[f_y(u')\mid\mathcal F_{j+1}] \ge f_y\bigl(\E[u'\mid\mathcal F_{j+1}]\bigr).

This is the required lower bound for the reaction. The exterior bounds and the exterior equality are deterministic and pass to the average.

Lemma 9.3 (Integrated error). Starting with u=b_{r_0} and d_0=0, the preceding construction reaches scale r_n=r_* and produces a deterministic error density with

\int d_n\le C M r_*^{17-3w}=o(M) \qquad\text{along the contradiction sequence}. \tag{9.7}

The constant is independent of the number of scales and of the nuclear configuration.

Proof. Since r_0<Z^{-1/3}\le a, Lemma 7.6 gives the initial invariant everywhere; there is no initial core region.

At scale r=r_j, apply Lemma 8.4 to the three increments in (). The high-failure estimate pays \mu_j on the gain region; the low-failure estimate pays T_y(H)=f_y(H)/(4\pi) on the remaining participating region. The same Lemma pays membership in \mathcal E and the penalty Laplacian. For \mathcal B\in\{\mathcal B^{\mathrm h},\mathcal B^{\mathrm l}\}, use \1_{\mathcal E\cup\mathcal B}\le\1_{\mathcal E}+\1_{\mathcal B}. All these integrands are nonnegative, so restriction to the indicated subregions only improves their bounds. We obtain

\E\int(\widetilde d-d_j)\le C M r^{17-3w}.

Conditional averaging preserves the unconditional expected integral of a nonnegative density. Because \beta=17-3w>0,

\sum_{j=0}^{n-1}r_j^\beta =r_*^\beta\sum_{h=1}^{n}2^{-h\beta} \le\frac{r_*^\beta}{2^\beta-1}.

At the last step the data are trivial, so d_n is deterministic. This proves (9.7), uniformly in n. The argument has used the failure probability separately at each spatial point and then integrated it; it has imposed no simultaneous good-data event in space.

9.3 The total-charge comparison

We have reached the unconditional density \mu_n and replaced the reaction by this density throughout \{a<r_*\}, at total error o(M). A final potential comparison converts this statement to a bound on the number of electrons in that region.

Proof of Theorem 1.1. Use the contradiction sequence and sector eigenstates of Section 8. Its terminal scale is r_*=(B_0M/K_{\mathrm{exc}})^{1/3}. The universal B_0 will exceed the fixed count constant below. All deterministic parameters and tolerances are chosen before taking the sequence limit. The smallness requirements of the preceding lemmas then hold for all its sufficiently late members, uniformly over their scales.

At the final step put

U=V_c+u_n,\qquad S=\nu-\1_{\{a<r_*\}}\mu_n+d_n.

The signed measure S has compact support. In fact \{a<r_*\} lies in a finite union of balls around the nuclei, the error density has compact support, and the nuclei are finite. Since \Delta V_c=-4\pi\nu+4\pi\nu_s, the final invariant implies

\Delta(U-K*S)\ge\1_{\{a\ge r_*\}}f_y(u_n)\ge0.

The nuclear singularities cancel in the explicit identity

U-K*S =u_n-V_s+K*(\1_{\{a<r_*\}}\mu_n)-K*d_n. \tag{9.8}

The right-hand side is continuous and locally H^1 on all of \R^3: the last two potentials have bounded compactly supported densities, and the other terms have the stated regularity from the construction.

Far from the nuclei, (9.2) gives U=B_{r_*}=W_0+q_0-\Gamma_{r_*}, which tends to zero by the deterministic field estimates. The compact source potential K*S also tends to zero. For every \epsilon>0, the function (U-K*S-\epsilon)_+ consequently has compact support and is an admissible H^1 test in the subharmonic inequality. Testing gives a nonpositive squared gradient norm, so this positive part vanishes. Letting \epsilon\downarrow0 proves

U\le K*S\qquad\text{away from the nuclear points}.

On every sufficiently large sphere U=B_{r_*}\ge .9W_0>0. The spherical mean of the potential of a compactly supported signed measure, on a sphere centered at the origin and enclosing its support, equals its total mass divided by the sphere radius. Hence

0<\int\dd S =Z-N+\int_{\{a\ge r_*\}}\mu_n+\int d_n. \tag{9.9}

Only positivity on a far sphere is used here; no asymptotic charge formula for W_0 is needed.

At the last scale the data have been completely averaged away, so

\mu_n(y)=\E_\Psi\sum_i\mathcal K_{x_i}(y).

If a kernel centered at x contributes to a point with a_y\ge r_*, then its support and the Lipschitz scale estimate imply

a_y\le a_x+\frac{|x-y|}{L} \le a_x\left(1+\frac{c_1r_*^w}{L}\right).

For small r_* this forces a_x\ge r_*/2. Each kernel has integral one, and Lemma 6.2 therefore gives

\int_{\{a\ge r_*\}}\mu_n \le\E_\Psi\#\{i:a(x_i)\ge r_*/2\} \le C M r_*^{-3}.

Combining this with (9.7) and (9.9) yields

K_{\mathrm{exc}}<C M r_*^{-3}+o(M) =\frac{C}{B_0}K_{\mathrm{exc}}+o(M).

Choose B_0>2C, increasing it also to ensure the initial scale choice in Section 8. Since K_{\mathrm{exc}}/M\to\infty, the last inequality is impossible. This proves the existence of one universal finite constant bounding the excess per nucleus in every strictly bound sector.

For an arbitrary strictly bound sector, the largest strictly bound sector of the same system has at least as many electrons, so the same bound applies. For every integer N>Z+CM, strict adjacent binding is therefore impossible. Sector monotonicity gives E_N\le E_{N-1}, and exclusion of the strict inequality gives E_N=E_{N-1}. Taking M=1 proves both atomic assertions for every real nuclear charge Z\ge1.

10 Conditional density and field comparisons

We now specialize to one nucleus at the origin and use V(y)=Z/|y|, d_y=|y|, and the atomic distance scale a_y=d_y/L with L=10^5. The comparisons in this section allow every real Z\ge1; the neutral-sector conclusions below use integer charges.

Fix 0\le D_0<\infty and a normalized ground state \Psi in a sector with n\le3Z and E_n\le E+D_0. The ground-state assumption in this section is used in the multiplier identity (2.4); the patch comparisons themselves apply to the resulting states with an energy offset. All probabilities below initially refer to the raw position-and-spin law of \Psi, enlarged by the explicitly specified independent random variables. The common likelihood and event-cost estimates of Section 5 now give a simultaneous comparison throughout an atomic annulus. This strengthens the pointwise molecular comparison by using the absence of nuclear singularities from these annuli.

10.1 Nested observations and master smoothing

Choose 0<\eps<1 and 0<s<1, and suppose Z is large enough that 2r_0\le s. Set

r_0=\eps Z^{-1/3},\qquad r_j=2^jr_0,\qquad m=\max\{j:r_j\le s\},\qquad \ell_j=r_j^{1.01}\quad(j<m). \tag{10.1}

Thus s/2<r_m\le s. At scale j<m observe the positions x_i+\ell_j U_{ji} and then forget the particle labels separately in each array. All Cartesian coordinates of all U_{ji}, at all scales, are independent with density

\zeta(u)=c_\zeta\exp\!\left(-\frac1{1-u^2}\right) \1_{\{|u|<1\}}.

Represent the unordered array by its lexicographically sorted tuple Y_j. Ties have probability zero. Write \mathcal F_j=\sigma(Y_j,\ldots,Y_{m-1}) and let \mathcal F_m be trivial. These sigma-fields decrease with j.

Fix w=10^{-5} and 0<c_1<(10L)^{-1}. With the same smooth radial packet g as in Section 3, define

\begin{gathered} D_x^0=\max(d_x,r_0),\qquad t_x=c_1D_x^0\min(D_x^0,s)^w,\qquad \mathcal K_x(y)=g_{t_x}(y-x)^2,\\ \mu_j(y)=\E\!\left[\sum_{i=1}^n\mathcal K_{x_i}(y) \,\middle|\,\mathcal F_j\right],\qquad H_j=V-K*\mu_j,\qquad \mathcal R f(y)=\int\mathcal K_z(y)f(z)\,\dd z. \end{gathered} \tag{10.2}

The lower clamp in D_x^0 is retained also for particles close to the nucleus; the upper clamp is only on the factor raised to w. In particular, t_x\ge t_{\min}:=c_1r_0^{1+w}>0 and t is Lipschitz with constant at most c_1(1+w)s^w.

Use the likelihood-ratio versions of Lemma 5.1 for these arrays and kernels. They give joint measurability, fixed-system derivative bounds, \mu_j\ge0, \int\mu_j=n, and

\E[\mu_j\mid\mathcal F_{j+1}]=\mu_{j+1},\qquad \E[H_j\mid\mathcal F_{j+1}]=H_{j+1}. \tag{10.3}

The offset H_j-V is locally Lipschitz and

\Delta H_j=-4\pi\nu+4\pi\mu_j. \tag{10.4}

Lemma 5.2 applies with baseline E_n and offset D_0. In particular, an event of probability p>0 at index j has tilted energy at most E+D_0+C\ell_j^{-2}\log^5(e/p). We retain this full baseline dependence throughout the argument.

10.2 The simultaneous inverse comparison

Proposition 10.1 (Conditional density determines the field). There is a universal constant C_{\rm cap} with the following property. Fix L_1\ge2, 0<h_l<h_h<\infty, and a sufficiently small \xi>0; it suffices to require \xi<h_l/16. There exists s_*=s_*(D_0,L_1,h_l,h_h,\xi)>0 such that, whenever 0<s\le s_*, at each j<m, with r=r_j, there is an event \mathcal G_j\in\mathcal F_j satisfying \Prob(\mathcal G_j^c)\le Cr^{25} on which, simultaneously for r\le d_y\le4L_1r and h_l\le h\le h_h,

\begin{aligned} d_y^6\mu_j(y)>kh^{3/2} &\quad\Longrightarrow\quad d_y^4H_j(y)\ge h-\xi,\\ d_y^6\mu_j(y)<kh^{3/2} &\quad\Longrightarrow\quad d_y^4H_j(y)\le h+\xi. \end{aligned} \tag{10.5}

On the same event, H_j(y)\le C_{\rm cap}d_y^{-4} throughout that band. The constant C may depend on the fixed parameters, whereas C_{\rm cap} does not depend on D_0,L_1,h_l,h_h,\xi. All estimates are uniform in Z, the ground state, j, and m.

Proof. We first control the observed count and the positive field throughout the band. At a fixed point and height, a hypothetical failure then defines a tilted state. Its fresh patch compares the observed density with the patch field, including the contribution of rare negative fields; the two expectation towers turn this into a contradiction. Finally, spatial and height nets give the simultaneous statement. Every occurrence of o(1) below tends to zero as s\downarrow0, uniformly for r_0\le r=r_j\le s and the stated bands, after the fixed parameters in the proposition have been chosen.

Kernel geometry. Put a=a_y=d_y/L, t=t_y and \tau=t/a. If \mathcal K_z(y)\ne0, the Lipschitz bound on t gives |z-y|\le t_z\le t_y+Cs^w|z-y|, hence |z-y|\le2t_y. On this support, t_z/t_y=1+O(s^w). Comparison with the fixed-width kernel g_t(y-z)^2 therefore gives

\int\mathcal K_z(y)\,\dd z=1+O(s^w),\qquad |\mathcal K_z(y)|\le Ct^{-3},\qquad |\nabla_y\mathcal K_z(y)|+|\nabla_z\mathcal K_z(y)|\le Ct^{-4}. \tag{10.6}

The center derivative is a weak derivative where t_z has a corner; its stated bound also gives the needed Lipschitz estimate. For r/2\le d_y\le8L_1r one has a\asymp_{L_1}r and

c_{L_1}a^w\le\tau\le Cs^w. \tag{10.7}

For example, when d_y\ge r_0, the formula is \tau=c_1L\min(d_y,s)^w; on the indicated band \min(d_y,s)\ge c_{L_1}d_y. The case d_y<r_0 is comparable, since d_y\ge r_0/2.

An observed-count event. Let M_j be the number of entries of Y_j with radii in [r/4,12L_1r]. For a sufficiently large fixed C_{L_1},

\Prob\{M_j>C_{L_1}r^{-3}\}\le r^{40}. \tag{10.8}

Indeed, if the event had probability p>r^{40}, its tilted raw state from Lemma 5.2 would have offset

\delta\le D_0+Cr^{-2.02}\log^5(e/r^{40}).

Each configuration compatible with the event has more than C_{L_1}r^{-3} raw points in [r/8,13L_1r], because observation displacements are at most \sqrt3\ell_j=o(r). But (4.45) bounds its expected count by C'_{L_1}(r^{-3}+\sqrt{\delta r})\le2C'_{L_1}r^{-3} for small s, a contradiction if C_{L_1}>2C'_{L_1}. Call the complementary event in (10.8) \mathcal C_j. For data in \mathcal C_j, every compatible configuration has at most C_{L_1}r^{-3} centers relevant to the master kernels on r/2\le d_y\le8L_1r. Conditional averaging and (10.6) imply there

\mu_j(y)\le Cr^{-6-3w},\qquad |\nabla\mu_j(y)|\le Cr^{-7-4w}. \tag{10.9}

A universal spatial field cap. Fix y in the same enlarged band and tilt an event A'=\{H_j(y)>b\,d_y^{-4}\} of positive probability p. The original-law tower gives

\E[H_j(y)\mid A'] =V(y)-\E_{\Psi_{A'}}\sum_i(K*\mathcal K_{x_i})(y) \le\E_{\Psi_{A'}}J_y.

To justify the last inequality, a master smear whose potential at y differs from the point potential has |x_i-y|<t_{x_i} and hence |x_i-y|\le2t_y<Aa_y for small s. All terms outside that exclusion therefore have their exact point potential, and dropping the remaining electron terms gives J_y. By (4.39) without an initial cut and Lemma 5.2,

b\le C_2+C_{L_1}r^{2.49}\log^{5/2}(e/p). \tag{10.10}

Here C_2 is universal: the local field term in these units is C d_y^4a_y^{-4}=CL^4, and the contribution C d_y^{7/2}\sqrt{D_0} is at most one after decreasing s. Solving (10.10) for p shows that for b\ge2C_2,

\Prob\{d_y^4H_j(y)>b\} \le e\exp\{-c_{L_1}(b-C_2)^{2/5}r^{-0.996}\}.

Tail integration consequently gives, for each fixed M>0,

\E(d_y^4H_j(y)-2C_2)_+\le C_{M,L_1}r^M.

Subharmonicity permits a simultaneous conclusion without a Z-dependent derivative estimate. Apply the ball submean inequality with radius d_y/10 for 3r/4\le d_y\le6L_1r. The averaging ball is contained in \{r/2\le d_z\le8L_1r\} and d_z\asymp d_y there, so

d_y^4H_j(y)\le C_3+Cr^{-3} \int_{\{r/2\le d_z\le8L_1r\}} (d_z^4H_j(z)-2C_2)_+\,\dd z.

The constant C_3 is universal. The integral term has expectation O_{M,L_1}(r^M), since its integration volume is O_{L_1}(r^3). Markov’s inequality proves that, outside an event of probability C_{M,L_1}r^M,

H_j(y)\le C_{\rm cap}d_y^{-4} \quad(3r/4\le d_y\le6L_1r),\qquad C_{\rm cap}=C_3+1. \tag{10.11}

This establishes the claimed order of dependence of the cap.

A fixed spatial point and height. Fix now r\le d_y\le4L_1r and h\in[h_l/2,2h_h]. Consider either failure of (10.5) with tolerance \xi/4, intersected with \mathcal C_j. If its probability were at least r^{42}, call that event A' and write Q=\Prob(\,\cdot\mid A'). The raw marginal is the state \Psi_{A'} of Lemma 5.2, with

\delta\le D_0+Cr^{-2.02}\log^5(e/r^{42}) \le a^{-7+.02} \tag{10.12}

for small s. Apply the refined patch (4.42) to this raw state at y, with \beta=a^{.2} and b=\beta a. Extend Q by fresh cut labels sampled conditional on the raw positions, exactly as in that patch. Let X be these patch data, let \rho_X^c be its conditional core density, and let \rho,W,\sigma be its minimizing density, screened field, and fine-smear density. Thus

W=V-K*\rho_X^c-K*\rho,\qquad \rho=kW_+^{3/2}\ \hbox{on the patch},\qquad \E_Q\left[D(\sigma-\rho)+\int W_-\sigma\right] \le Ca^{-7+.02}.

The roles of these densities and their laws are distinct. The pair \mu_j,H_j keeps its original-observation definition in (10.2). Under the event law Q, the fresh patch gives the conditional core density \rho_X^c and its field \Phi_X=V-K*\rho_X^c; \sigma is the fine smear of retained out particles, whereas \rho is the auxiliary minimizing density and W=\Phi_X-K*\rho. The field comparison is made after taking Q-expectations in (10.19) below.

Each compatible raw configuration matches the observed array Y_j after a permutation, with displacement at most \sqrt3\ell_j per position. Both configurations and their conditional averages at those same data therefore differ, when tested against x\mapsto\mathcal K_x(y), by at most Cr^{-3}\ell_jt^{-4}. This follows from the count bound and the center Lipschitz estimate in (10.6); only entries within 2t+O(\ell_j) of y can contribute. All such raw particles are retained by the fresh patch. Its radial fine smear moves a retained point by at most \sqrt3b, adding at most Cr^{-3}bt^{-4} to the error. Consequently, on every compatible path, including paths where the Coulomb error is large,

|\mathcal R\sigma(y)-\mu_j(y)| \le Cr^{-3}(\ell_j+b)t^{-4} \le Ca^{-6}\big(a^{.01}\tau^{-4}+a^{.2}\tau^{-4}\big) =o(a^{-6}). \tag{10.13}

In the comparison with the conditional average, one may first compare each raw sum with \sum_i\mathcal K_{Y_{j,i}}(y), then average this same bound using the original posterior law. The array is fixed in both comparisons, so no equality of posterior laws is being used.

Let G=\{D(\sigma-\rho)\le a^{-7+.01}\}. Then Q(G^c)\le Ca^{.01}. The test function z\mapsto\mathcal K_z(y) has support in B(y,2t) and gradient norm at most Ct^{-5/2}. Coulomb duality gives on G

|\mathcal R(\sigma-\rho)(y)| \le Ca^{-7/2+.005}t^{-5/2} =Ca^{-6}a^{.005}\tau^{-5/2}=o(a^{-6}). \tag{10.14}

The positivity of the two powers used so far is explicit: .01-4w=.00996 and .005-(5/2)w=.004975.

On G, a high-density antecedent forces

W(y)\ge(h-\xi/16)d_y^{-4}. \tag{10.15}

For if the reverse strict inequality held, the oscillation bound (4.44) on B(y,2t) would give W(z)\le(h-\xi/32)d_y^{-4} there for sufficiently small s. This remains uniform when W(y) is arbitrarily negative: the upper estimate is W(y)+C\tau(a^{-4}+W(y)_-), and v\mapsto v+C\tau v_- is increasing for C\tau<1. Using the patch equation and \int\mathcal K_z(y)\,\dd z=1+O(s^w) would then give

\mathcal R\rho(y) \le k(h-\xi/32)^{3/2}d_y^{-6}(1+O(s^w)) <kh^{3/2}d_y^{-6}-c_{h_l,h_h,\xi}a^{-6},

contradicting (10.13)–(10.14). Similarly, on G a low-density antecedent forces

W(y)\le(h+\xi/16)d_y^{-4}. \tag{10.16}

Indeed the contrary is positive, so the lower oscillation estimate gives W(z)\ge(h+\xi/32)d_y^{-4} on the contributing ball; its reaction density contradicts the low antecedent with the same strict margin. Constants from d_y=La are fixed before s is decreased.

The negative field on the exceptional patch event. The upper bound (10.16) passes to expectation with an o(a^{-4}) error, by the patch bound W(y)\le Ca^{-4} and Q(G^c)\le Ca^{.01}. To pass the lower bound to expectation we need more than this small probability. Under the high-density antecedent, (10.13) holds on all paths and gives \mathcal R\sigma(y)\ge ca^{-6}, since h\ge h_l/2>0. The support and upper bound of the master kernel imply the deterministic mass bound

M_\sigma:=\int_{B(y,2t)}\sigma\ge ca^{-6}t^3.

For Y=W(y)_-, (4.44) gives throughout this ball W(z)_-\ge(1-C\tau)Y-C\tau a^{-4}. Taking C\tau\le1/2, integrating against \sigma, and using the mass bound yields

Y\le C(a^{-6}t^3)^{-1}\int W_-\sigma+C\tau a^{-4}.

Multiply by \1_{G^c} and use the refined patch budget under the same law Q. We obtain

\E_Q[\1_{G^c}W(y)_-] \le Ca^{-4}\big(a^{.02}\tau^{-3}+\tau\big)=o(a^{-4}), \tag{10.17}

because .02-3w=.01997>0. Thus the high and low antecedents give, respectively,

\E_QW(y)\ge(h-\xi/16)d_y^{-4}-o(a^{-4}),\qquad \E_QW(y)\le(h+\xi/16)d_y^{-4}+o(a^{-4}). \tag{10.18}

Transfer between the two conditioning procedures. Apply Lemma 5.3 with V_s=V, V_c=0 and h_X=W. Its two towers are taken under the original observation law and the fresh tilted patch law, respectively. The refined patch provides all its inputs: the raw density bound and Coulomb budget are (4.42), the deleted count bound is (4.26), and \rho\le Ca^{-6} on the contributing ball by (4.25). Therefore

|\E_Q(H_j-W)(y)| \le Ca^{-4}\{\tau^{1/5}+\beta^{1/5}+\sqrt\beta +a^{.01}\tau^{-1/2}+\tau^{1/2}\}=o(a^{-4}). \tag{10.19}

Here \beta=a^{.2} and (10.7) makes every positive-power error vanish. The source-free potential remainder actually has the sharper power \tau^2, so the common upper bound is sufficient. No equality of posterior laws is used in this transfer.

On a high-failure event, its defining inequality is d_y^4H_j(y)<h-\xi/4, whereas (10.18) and (10.19) give d_y^4\E_QH_j(y)\ge h-\xi/16-o(1), a contradiction for small s. On a low-failure event the inequalities are reversed and give the same contradiction. Thus each such failure intersected with \mathcal C_j has probability less than r^{42}. Including (10.8), the two implications at a fixed point and height, with tolerance \xi/4, fail with probability at most Cr^{40}.

Spatial and height nets. Choose a net of the closed band \{r\le d_y\le4L_1r\} with spacing at most r^2 and at most C_{L_1}r^{-3} points. For example, select one band point in each intersecting cube of side r^2/2; the cube count follows from the volume of its O(r^2) enlargement. Choose a finite height net in [h_l/2,2h_h] with mesh at most \xi/64, including its endpoints. Exclude every point-and-height failure, the count failure, and the cap failure with M=40 in (10.11). A union bound gives exceptional probability Cr^{37}, and hence at most Cr^{25} for r<1.

On the retained event, (10.9) shows that d_y^6\mu_j(y) varies by at most Cr^{1-4w}=o(1) between a band point and a net point within Cr^2. To control the field, work in a ball of radius cr around a band point, contained in the enlarged cap band. On this ball B, let Q=K*(\1_B\mu_j). Then H_j+Q is harmonic on B. The value and gradient of Q are bounded by Cr^{-4-3w} and Cr^{-5-3w}, respectively, so H_j+Q is bounded above by Cr^{-4-3w}. Its nonnegative distance from that upper bound has, by the Poisson formula on a smaller concentric ball, oscillation bounded by its central value times the relative distance. It follows that

|H_j(z)-H_j(y)| \le Cr\big(r^{-4-3w}+H_j(y)_-\big) \quad(|z-y|\le Cr^2). \tag{10.20}

This estimate also controls the change of the normalized field d_y^4H_j(y), since d_z/d_y=1+O(r). In particular, if its value at y is below h-\xi, its value at z is below h-3\xi/4 for small s. Arbitrarily negative values cause no problem: the relevant upper estimate has the form v+Crv_-+O(r^{1-3w}), increasing in v when Cr<1. If the value at y exceeds h+\xi, it is positive and the cap and (10.20) make its value at z greater than h+3\xi/4.

Suppose now a high-density implication failed at some (y,h). At a nearby spatial net point choose a height-net value h'\in[h-\xi/4,h-\xi/8]. The positive lower height bound and the o(1) density variation preserve the high antecedent at h', while the field is below h-3\xi/4<h'-\xi/4. This is an excluded net failure. For a low-density failure choose h'\in[h+\xi/8,h+\xi/4]; its antecedent is preserved and the field exceeds h+3\xi/4>h'+\xi/4. The height intervals lie inside [h_l/2,2h_h] by the stipulated smallness of \xi. This proves simultaneity and finishes the proposition.

We record also an unconditional estimate used to pay for a failed band. For fixed L_1 and r\le d_y\le4L_1r, the support and size of the master kernel, conditional Jensen, and (4.45) in the original state give

\|\mu_j(y)\|_2 \le Ct_y^{-3} \left\|\#\{i:r/2<d_{x_i}<8L_1r\}\right\|_2 \le Ct_y^{-3}r^{-3}\le Cr^{-6-3w}. \tag{10.21}

The middle inequality uses the offset D_0 and sufficiently small s; its constant is uniform in the state and scale.

The order of choices is relevant. The fixed screening constants, g,c_1,w, and the universal cap C_{\rm cap} come first. One may then choose L_1,h_l,h_h,\xi and a bounded offset D_0, and finally make s small enough for every estimate above. Thereafter any sufficiently large Z with 2r_0\le s is permitted. In particular no step requires D_0=0, and the number of dyadic scales introduces no loss in the constants.

11 Outward propagation and an electron deficit

The conditional comparisons let us extend a prescribed electron source from the scale Z^{-1/3} to a small radius independent of Z. The result applies to ground states whose energy has a bounded offset from the minimum over all particle numbers.

Proposition 11.1 (Deficit inside a fixed small ball). There is a universal constant c_{\mathrm{def}}>0 with the following property. For every D_0\in[0,\infty) there is s_*(D_0)>0 such that, for each 0<s\le s_*(D_0), there is an integer Z_*(D_0,s) for which every integer Z\ge Z_*(D_0,s) and every normalized sector ground state \Psi satisfying

n\le3Z,\qquad q_n[\Psi]=E_n\le E+D_0

obey

Z-\E_\Psi\#\{i:|x_i|<s/4\} \ge c_{\mathrm{def}}s^{-3}>1. \tag{11.1}

All thresholds are independent of the sector and of the choice of its ground state. In particular, admissible fixed radii s can be taken arbitrarily small.

To prove the deficit, we construct fields u_j satisfying a lower bound for their Laplacian. Alongside the nuclear term -4\pi\nu, this bound uses the conditional density term 4\pi\mu_j inside radius r_j and the model reaction 4\pi k(u_j)_+^{3/2} outside. Each outward step replaces that reaction by the actual density on one more annulus, then forgets the current observation array. An error density records the source omitted on exceptional data. A positive lower barrier and a small expected error will force a positive residual charge at the terminal scale. The construction also gives the following result at every intermediate stopping index.

Proposition 11.2 (Intermediate atomic subsolutions). There are universal constants \eps,B,C_{\rm inv}>0 and L_1>2 with the following property. Fix D_0<\infty, then take s>0 sufficiently small and integer Z sufficiently large as in Proposition 11.1. For every sector ground state in that proposition use the common observations and master packets (10.1)–(10.2), with r_0=\eps Z^{-1/3} and s/2<r_m\le s. For each 0\le j\le m there exist jointly measurable \mathcal F_j-measurable fields u_j and densities p_j^{\rm err} with the following properties. Put d=|y|, r=r_j, and f(t)=4\pi k(t_+)^{3/2}, and define

b_r(y)=Bd^{-4}\left(1-\frac r{8d}\right)\quad(d\ge r).
\begin{split} \Delta u_j&\ge-4\pi\nu+4\pi\1_{\{d<r\}}\mu_j -4\pi p_j^{\mathrm{err}}+\1_{\{d\ge r\}}f(u_j),\\ b_r\le u_j&\le C_{\mathrm{inv}}d^{-4}\quad(d\ge r), \qquad u_j=b_r\quad(d>L_1r). \end{split} \tag{11.2}

The differential inequality is global in distributions. The offsets u_j-V are continuous and locally Lipschitz on all of \R^3; p_j^{\rm err}\ge0 is bounded and supported in |y|\le r_j. For each fixed system and step, the offsets have deterministic size and Lipschitz bounds on every compact set; the errors have deterministic size bounds. Universally,

\E\int p_j^{\rm err} \le C r_0^{32}+C\sum_{i<j}r_i^{19/2-3w} \le C\left(r_0^{32}+r_j^{19/2-3w}\right),\qquad w=10^{-5}. \tag{11.3}

In particular this is at most C(s^{32}+s^{19/2-3w}). The expectations cannot in general be omitted for j<m; the terminal fields are deterministic. The same master kernels are used at every intermediate stopping index. The constants \eps,B,C_{\rm inv},L_1 are independent of any additional inverse-comparison parameters. Such a comparison uses these same observations whenever its own smallness condition on s is met.

Proof of Propositions 11.2 and 11.1. Use the observations and master packets (10.1)–(10.2), with \eps fixed during initialization below and Z large enough that m\ge1. The resulting densities and fields satisfy

\E[\mu_j\mid\mathcal F_{j+1}]=\mu_{j+1},\qquad \E[H_j\mid\mathcal F_{j+1}]=H_{j+1}. \tag{11.4}

Write \kappa=1/8. The barrier b_r in the proposition is positive on d\ge r and, for sufficiently small fixed B>0, satisfies

\Delta b_r=Bd^{-6}(12-20\kappa r/d) \ge\frac{19}{2}Bd^{-6}\ge f(b_r). \tag{11.5}

For example, 4\pi k\sqrt B\le19/2 suffices. If R=2r, then

b_r-b_R=B\kappa r d^{-5}\ge\gamma R^{-4} \quad(R\le d\le1.1R),\qquad \gamma=\frac{B\kappa}{2(1.1)^5}>0. \tag{11.6}

Initialization. With probability at least 1-Cr_0^{35}, the initial conditional density satisfies

P_0(y):=K*(\1_{\{d<r_0\}}\mu_0)(y) \le0.1\,Z/r_0\qquad(r_0\le |y|\le1.1r_0). \tag{11.7}

To prove this, fix a point y in this annulus and let A_y=\{P_0(y)>0.05Z/r_0\}, an event of \mathcal F_0. Suppose that p=\Prob(A_y)>r_0^{40}. By Lemma 5.2, the raw marginal conditioned on this event is the squared law of an antisymmetric state of offset at most

D_0+C r_0^{-2.02}\log^5(e/r_0^{40}).

For the fixed \eps this is at most Z^{7/3} when Z is large enough. The global estimate (3.3) therefore bounds the tilted density \rho_{A_y} by \int\rho_{A_y}^{5/3}\le C Z^{7/3}, with a universal C.

Only packet centers with |x|<2r_0 can contribute to the truncated density in P_0: a center outside this ball has t_x\le c_1s^w|x|<|x|/2, so its packet misses B(0,r_0). A truncated packet has potential at most that of the full packet, which by radial smearing is at most K(y-x). The conditional tower identity and Hölder’s inequality consequently give

\begin{align*} \E[P_0(y)\mid A_y] &\le\int_{|x|<2r_0}\frac{\rho_{A_y}(x)}{|y-x|}\,\dd x\\ &\le C Z^{7/5}r_0^{1/5} =C\eps^{6/5}\,Z/r_0.\end{align*}

Choose \eps small enough that the last coefficient is less than 0.05. This contradicts the definition of A_y, so \Prob(A_y)\le r_0^{40}.

The minimum packet width is t_{\min}=c_1r_0^{1+w}. Integrating |y-z|^{-2} against a bounded packet gives the deterministic bound

\|\nabla P_0\|_\infty\le Cn t_{\min}^{-2} \le C Z r_0^{-2-2w}.

A net in the annulus of spacing O(r_0^2) has O(r_0^{-3}) points. The union bound gives failure probability O(r_0^{37}), and the variation between a point and its net point, divided by Z/r_0, is O(r_0^{1-2w})=o(1). For large Z this proves (11.7), with the stated weaker exponent 35.

Let G_0 denote the event in (11.7), and set

\mu^{\mathrm{in}}=\1_{G_0}\1_{\{d<r_0\}}\mu_0, \qquad p_0^{\mathrm{err}}=\1_{G_0^c}\1_{\{d<r_0\}}\mu_0.

On d<2r_0 use the branch

v=V-K*\mu^{\mathrm{in}}-0.7Z/r_0 +C_3(Z/r_0)^{3/2}d^2.

Choose C_3 universally so that 6C_3\ge4\pi k2^{3/2}, and then choose \eps sufficiently small to meet the preceding tilt condition and 4C_3\eps^{3/2}\le0.05. The quadratic term on this ball is at most 0.05Z/r_0, since Zr_0^3=\eps^3. For r_0\le d<2r_0 we thus have v\le2Z/r_0 and

\Delta v=-4\pi\nu+4\pi\mu^{\mathrm{in}} +6C_3(Z/r_0)^{3/2}, \qquad 6C_3(Z/r_0)^{3/2}\ge f(v).

On r_0\le d<1.06r_0, the good-event bound (and the easier bound \mu^{\mathrm{in}}=0 on its complement) give

v\ge(1/1.06-0.1-0.7)Z/r_0>0.14Z/r_0.

On 1.9r_0<d<2r_0 we instead have v\le(1/1.9-0.7+0.05)Z/r_0<0. Fix B satisfying the barrier condition and 0<B\le0.1\eps^3. Then v>b_{r_0} on the lower overlap, whereas v<0<b_{r_0} on the upper overlap. Define

u_0=\begin{cases} v,&d<1.06r_0,\\ \max(v,b_{r_0}),&r_0<d<2r_0,\\ b_{r_0},&d>1.9r_0. \end{cases}

The definitions agree on their open overlaps. Lemma 5.4 proves (11.2) initially; near d=r_0 the branch v alone attains the maximum, and its displayed Laplacian supplies both required densities. The exterior upper bound holds, for example, when C_{\mathrm{inv}}\ge\max(B,32\eps^3). Also, using n\le3Z=3\eps^3r_0^{-3},

\E\int p_0^{\mathrm{err}} \le n\Prob(G_0^c)\le C r_0^{32}. \tag{11.8}

Order of the remaining constants. The constants C_3,\eps,B have now been fixed universally. Increase C_{\mathrm{inv}} to exceed also the universal cap C_{\mathrm{cap}} in Proposition 10.1. After fixing \gamma in (11.6), choose 0<\lambda_2<\lambda_1<\gamma/2. Choose L_1>2 so large that C_{\mathrm{inv}}L_1^{-4}<\lambda_2. This ensures

C_{\mathrm{inv}}d^{-4}-\lambda_2R^{-4}<b_R \qquad(d>L_1R).

Next fix 0<h_l<B/4 and h_h>C_{\mathrm{inv}}, and then choose e_0,\xi>0 sufficiently small that

2e_0(2L_1)^4<B/4,\qquad 16\xi+2e_0<\lambda_1-\lambda_2,\qquad \xi<\lambda_2, \tag{11.9}

with \xi also in the range of Proposition 10.1. Only now restrict s according to that proposition, D_0, and the other smallness conditions in this proof. Finally take Z large according to D_0,s and the initialization requirements. Thus no constant is chosen in terms of a later scale or a particular state.

One outward step. Suppose that (11.2) holds at r=r_j, write R=2r, and abbreviate u=u_j. On the good band event of Proposition 10.1, for the band r\le d\le4L_1r=2L_1R, introduce

v_1=u-\lambda_1R^{-4},\qquad v_2=H_j-\lambda_2R^{-4}.

Define a new function on a fixed open cover by

\begin{array}{c|c} \text{region}&u'\\ \hline d<1.08R&\max(v_1,v_2)\\ 1.04R<d<2L_1R&\max(v_1,v_2,b_R)\\ d>L_1R&b_R. \end{array} \tag{11.10}

On bad band data omit v_2 in every row. In both cases set

\widetilde p=p_j^{\mathrm{err}} +\1_{\{\mathrm{bad}\}}\1_{\{r\le d<R\}}\mu_j. \tag{11.11}

On the lower overlap, (11.6) gives v_1\ge b_r-\lambda_1R^{-4}>b_R. On the upper overlap, the caps on u and, on good data, H_j put both shifted branches below b_R. The definitions therefore agree. For R\le d<1.08R the lower bound u'\ge b_R follows already from v_1; farther out the barrier is included explicitly. The upper bound u'\le C_{\mathrm{inv}}d^{-4} and the equality u'=b_R for d>L_1R follow from the same caps.

We prove the distributional inequality at radius R before averaging. The open-neighborhood formulation is as follows. At a point y_0 in one of the open sets of (11.10), let M be the maximum of its candidate family and put \eta=e_0R^{-4}. Keep precisely those candidates v with M(y_0)-v(y_0)\le\eta, and choose a maximizer v_* at y_0. Continuity and finiteness give an open neighborhood U of y_0, inside the chosen open set, on which every discarded candidate is strictly below v_* and every retained candidate satisfies

M-v<2e_0R^{-4}. \tag{11.12}

The retained family has maximum M throughout U. At the origin make this construction with the continuous offsets by V; the family there contains only branches having that common singularity.

Each retained branch satisfies on the whole of this neighborhood the common inequality

\Delta v\ge-4\pi\nu+4\pi\1_{\{d<R\}}\mu_j -4\pi\widetilde p+\1_{\{d\ge R\}}f(v). \tag{11.13}

For v_1, retain its old distributional inequality and compare its right side with the new one almost everywhere. On d<r the old source suffices. On d\ge R, use f(u)\ge f(v_1). On the gain region r\le d<R, bad data are paid by the added error in (11.11). On good data, v_2 is a candidate there, so (11.12) gives

H_j\le u-(\lambda_1-\lambda_2-2e_0)R^{-4}.

Moreover h_l<7B/8\le d^4u\le C_{\mathrm{inv}}<h_h. If 4\pi\mu_j>f(u), the high implication in (10.5), at height h=d^4u, would give

H_j\ge u-\xi d^{-4}\ge u-16\xi R^{-4},

contrary to (11.9). Hence 4\pi\mu_j\le f(u), and the old reaction supplies the added source.

For v_2, which occurs only on good data, start from its identity on all of U,

\Delta v_2=-4\pi\nu+4\pi\mu_j.

This supplies (11.13) on d<R, since \widetilde p\ge0. At any remaining point where v_2 is retained, the lower splice or the included barrier gives M\ge b_R, and d\le2L_1R. Thus

d^4v_2\ge B(1-\kappa R/d)-2e_0(d/R)^4 \ge7B/8-2e_0(2L_1)^4>5B/8>h_l.

The cap also gives d^4v_2\le C_{\mathrm{cap}}<h_h. If 4\pi\mu_j<f(v_2), the low implication in (10.5), with h=d^4v_2, would imply

H_j\le v_2+\xi d^{-4} \le v_2+\xi R^{-4}<v_2+\lambda_2R^{-4}=H_j,

which is impossible. Consequently 4\pi\mu_j\ge f(v_2) there. The barrier branch occurs only where d>R and satisfies the common inequality by (11.5).

These verifications compare zero-order densities almost everywhere on the same open set U; they do not restrict or differentiate a weak inequality across an activity set or a sphere. In particular they apply on a neighborhood crossing d=R. The common reaction is F(y,t)=\1_{\{d\ge R\}}f(t), which meets Lemma 5.4’s hypotheses after canceling V near the origin. That lemma proves (11.13) for the local maximum. These local conclusions give the inequality globally by a partition of unity. We have proved the desired invariant at radius R with density \mu_j, function u', and error \widetilde p.

Forgetting the current observations. Define the next offset and error by conditional integration,

u_{j+1}=V+\E[u'-V\mid\mathcal F_{j+1}],\qquad p_{j+1}^{\mathrm{err}}=\E[\widetilde p\mid\mathcal F_{j+1}].

We give the regularity justification as well as the formal calculation. For the fixed system t_{\min}>0, and integration of each packet gives deterministic bounds

\|\mu_j\|_\infty\le Cnt_{\min}^{-3},\qquad \|K*\mu_j\|_\infty\le Cnt_{\min}^{-1},\qquad \|\nabla K*\mu_j\|_\infty\le Cnt_{\min}^{-2}.

The same potential bounds hold for the initially truncated density. The explicit initial branches therefore have deterministic local Lipschitz bounds for their offsets. Subtracting a constant and taking a finite maximum preserve such bounds. Where b_R occurs, its offset b_R-V is smooth and separated from the origin. The fixed open cover and agreement on overlaps preserve local bounds after gluing. The errors are bounded, nonnegative, and supported in a deterministic ball. Induction supplies all the claimed bounds at every step, without requiring them to be uniform in Z.

All functions are jointly measurable in data and position. Indeed the conditional densities have the likelihood versions described in Section 10; the initialization flag is a supremum of a continuous function on a fixed compact annulus, testable on a countable dense set; and the band flags and finite maxima are measurable. Conditional integration of functions with deterministic local Lipschitz bounds preserves those bounds. It also commutes with weak derivatives by Fubini. Nonnegative smooth tests in a countable dense family first give simultaneous almost-sure weak inequalities; local bounds extend them to every test. Thus the following conditional integration is legitimate as an inequality of distributions.

Integrate (11.13) conditionally on \mathcal F_{j+1}. The tower property supplies \mu_{j+1}, while convexity gives

\E[f(u')\mid\mathcal F_{j+1}] \ge f\bigl(V+\E[u'-V\mid\mathcal F_{j+1}]\bigr).

The deterministic bounds b_R\le u'\le C_{\mathrm{inv}}d^{-4} and the equality outside L_1R pass to this average. Positivity, boundedness, and support of the error do as well. This proves (11.2) at step j+1.

Summing the lost source. For r\le d_y<2r, every master packet contributing to \mu_j(y) has its center in a fixed annulus comparable to r, and its width is comparable to t_y. Conditional Jensen and the annular count estimate (4.45), applied with offset at most D_0, yield

\|\mu_j(y)\|_2\le Ct_y^{-3}r^{-3} \le Cr^{-6-3w}.

Here r\le s\le1 and s is small according to D_0, so \max(r^{-3},1)+\sqrt{D_0r}\le Cr^{-3}. The bad band probability is at most Cr^{25} by Proposition 10.1. Cauchy–Schwarz in data and integration over the gain annulus give

\E\int(\widetilde p-p_j^{\mathrm{err}}) \le C r^{25/2}r^3r^{-6-3w} =Cr^{\alpha},\qquad \alpha=\frac{19}{2}-3w>0.

Conditional averaging preserves the expected integral. Stopping the sum before any index j and using (11.8) proves (11.3), with the same master kernels and without replacing an expectation by a pathwise bound. At the terminal index the geometric progression of radii gives

\int p_m^{\mathrm{err}} =\E\int p_m^{\mathrm{err}} \le Cr_0^{32}+C\sum_{j=0}^{m-1}r_j^\alpha \le C(s^{32}+s^\alpha). \tag{11.14}

The last error is deterministic because \mathcal F_m is trivial. The constants are independent of the number of scales and of Z.

From the potential to the raw electron count. Put r=r_m, u=u_m, and introduce the compactly supported signed measure

S=\nu-\1_{\{d<r\}}\mu_m\,\dd y+p_m^{\mathrm{err}}\,\dd y.

The invariant implies \Delta(u-K*S)\ge0. Its singularities cancel in the identity

u-K*S=(u-V)+K*(\1_{\{d<r\}}\mu_m)-K*p_m^{\mathrm{err}},

whose right side is continuous and locally H^1 on all of \R^3. The difference tends to zero at infinity: u=b_r outside L_1r, and the potential of the finite compact source S tends to zero. For each a>0, the positive part (u-K*S-a)_+ has compact support and is an admissible H^1 test in its subharmonic inequality. Testing gives a nonpositive squared gradient integral, hence this positive part vanishes. Letting a\downarrow0 proves u\le K*S.

On the sphere d=2r, the invariant gives u\ge b_r(2r)=15B r^{-4}/256. The spherical mean of K*S there equals the total mass of S divided by 2r, since S is supported in \{d\le r\}. Consequently

Z-\int_{d<r_m}\mu_m+\int p_m^{\mathrm{err}} \ge\frac{15B}{128}r_m^{-3}. \tag{11.15}

No sign condition on the measure S is needed for this mean identity.

Finally \mu_m is the unconditional master-smoothed density. If |x|<s/4, then r_0\le s/2 and D_x^0\le s/2, so t_x\le c_1(s/2)s^w<s/4. The packet at x is therefore wholly contained in B(0,s/2)\subset B(0,r_m). Since every packet has mass one,

\E_\Psi\#\{i:|x_i|<s/4\}\le\int_{d<r_m}\mu_m.

Combining this with (11.15), (11.14), and r_m\le s gives

Z-\E_\Psi\#\{i:|x_i|<s/4\} \ge\frac{15B}{128}s^{-3}-C(s^{32}+s^\alpha).

Take c_{\mathrm{def}}=15B/256 and decrease s_*(D_0) so that the error is at most c_{\mathrm{def}}s^{-3} and c_{\mathrm{def}}s^{-3}>1 for every 0<s\le s_*(D_0). All remaining requirements are met by increasing Z_*(D_0,s). This proves the proposition.

12 Returning to the neutral sector

The deficit estimate was proved for ground states whose energy is within a fixed distance of the minimum over all particle numbers. We first apply it at that minimum. A screened deletion comparison will then put the neutral and singly ionized ground states in the same class.

We record explicitly the harmonic-field estimate used in the deletion and again in the final tail argument. For a configuration \omega=(x_i,\sigma_i)_{i=1}^n and h>0, write

B_h(x;\omega)=V(x)-\sum_{|x_i|<h}K(x-x_i). \tag{12.1}

This field is harmonic on \{|x|>h\}, configuration by configuration.

Lemma 12.1 (Conditional fields on annuli). Fix positive constants \alpha<\alpha'<\beta'<\beta and \alpha_0<\beta_0. Let u>0, 0<h\le\alpha u/2, and let \psi be a normalized \delta-state with n\le3Z, where \delta<\infty is arbitrary. Let Y be the data from a cut whose out support lies in \{\alpha_0u<|x|<\beta_0u\} and whose squared gradient cost is at most C u^{-2}. The cut may also be absent, in which case Y is trivial. There is a jointly measurable version

H_Y(x)=\E_\psi[B_h(x)\mid Y]

which is harmonic on \{\alpha u<|x|<\beta u\} for almost every datum. Put

M(Y)=\sup_{\alpha'u\le|x|\le\beta'u}(H_Y(x))_+.

Then

\|M\|_2\le C\left\{ \frac{\max(u^{-3},1)+\sqrt{\delta u}}{u} +\sum_{j=0}^\infty \frac{\max((2^jh)^{-3},1)+\sqrt{\delta\,2^jh}} {\max(u,2^jh)}\right\}. \tag{12.2}

The constant depends only on the fixed annular ratios and cut-gradient constant, in addition to the fixed screening constants L,A. In particular it does not depend on n,Z,\delta,h,u.

Proof. For x in the broad annulus, every source with |x_i|<h lies outside B(x,Aa_x): indeed h\le|x|/2 and A/L<1/2. Consequently

B_h(x)=J_x+ \sum_{\substack{|x_i|\ge h\\|x_i-x|\ge Aa_x}}K(x-x_i). \tag{12.3}

If 2^jh\le|x_i|<2^{j+1}h and the summand occurs, then

K(x-x_i)\le\frac{C}{\max(u,2^jh)}.

For radii comparable to or below u this follows from the exclusion |x_i-x|\ge Aa_x\ge A\alpha u/L; for radii greater than 2\beta u it follows from |x_i-x|\ge|x_i|/2.

The initial-cut hypotheses of Proposition 4.5 hold uniformly here. Cover its support by a fixed finite number of cells B_z with a_z\asymp u, the constants being allowed to depend on L and the annular ratios. For each target x in the broad annulus these cell scales are comparable to a_x. The gradient bound can be written as \sum_zD_z^2a_z^{-2}\1_{B_z}, with D_z^2\le C(a_z/u)^2. Since a_zm_z\ge1 and the screening parameter P\ge1,

\frac{D_z^2}{a_zm_z}\le C\le C_0\sqrt P.

Enlarging the fixed cover constant C_0 suffices for every finite \delta. Thus (4.39), conditional Jensen, the triangle inequality in L^2, and (4.45) applied to (12.3) give, pointwise in the spatial variable,

\|(H_Y(x))_+\|_2\le C\left\{ \frac{\max(u^{-3},1)+\sqrt{\delta u}}{u} +\sum_{j\ge0} \frac{\max((2^jh)^{-3},1)+\sqrt{\delta\,2^jh}} {\max(u,2^jh)}\right\}.

The series converges: its large-j terms are bounded by a constant times 2^{-j}h^{-1}+\sqrt\delta\,2^{-j/2}h^{-1/2}.

For completeness, conditional fields here have simultaneous spatial versions. On every compact subset of \{|x|>h\}, the kernels in (12.1) and each fixed number of their derivatives have deterministic bounds for the fixed finite system. Conditional integration therefore gives continuous harmonic functions, with measurable dependence on the data. One may first use the conditional law of configurations supplied by the cut and then differentiate under that integral. For a harmonic function H, its positive part is subharmonic. Balls of radius c u about points of the smaller annulus remain in the broad annulus, so their mean-value inequalities imply

\sup_{\alpha'u\le|x|\le\beta'u}H(x)_+ \le C u^{-3}\int_{\alpha u<|z|<\beta u}H(z)_+\,\dd z.

Minkowski’s integral inequality and the pointwise bound prove (12.2). Suprema can be taken on countable dense sets, which also proves their measurability.

Two forms of this estimate will be used. With fixed t>0, h=t/4, u=2^\ell t, and \delta=0, it gives for the positive conditional supremum on u\le|x|\le2u the bound

\|M\|_2\le C_t\frac{1+\ell}{u}. \tag{12.4}

Indeed the terms with 2^jh\le u have total numerator at most C_t(1+\ell), and the remaining series is O_t(u^{-1}). With h=u/8, u\ge1, and the smaller annulus u/2\le|x|\le4u, the broad annulus u/4<|x|<6u is admissible and gives

\|M\|_2\le C\big(u^{-1}+\sqrt\delta\,u^{-1/2}\big). \tag{12.5}

In the first application the broad annulus can be u/2<|x|<3u. The non-strict equality h=\alpha u/2 causes no boundary issue, since the broad annulus is open and still separated from the sources.

Lemma 12.2 (An upper bound on an inner deficit). For each fixed t>0 and every normalized \delta-state with n\le3Z,

Z-\E\#\{i:|x_i|<t/4\}\le C_t(1+\sqrt\delta). \tag{12.6}

Proof. Use Lemma 12.1 with no cut, h=t/4, and u=t. Its convergent series is bounded by C_t(1+\sqrt\delta). The spherical average of the expected field B_{t/4} on |x|=t equals

\frac{Z-\E\#\{i:|x_i|<t/4\}}{t},

by the spherical mean of the Coulomb kernel. Bounding this average from above by the positive supremum proves the assertion, with the fixed factor t absorbed into C_t.

Proposition 12.3 (A bounded offset for neutral sectors). There are universal constants C,Z_0<\infty such that, for Z\ge Z_0,

E_{Z-1}\le E+C. \tag{12.7}

Proof. Take a normalized ground state \Psi_* in sector N_*, where Z\le N_*\le3Z and E_{N_*}=E, as provided by Lemma 2.6. Proposition 11.1, with D_0=0, supplies a fixed sufficiently small t>0 such that

\E_{\Psi_*}\big[Z-\#\{i:|x_i|<2t\}\big]>1

for all sufficiently large Z. Choose a smooth square partition c^2+o^2=1, with c=1 on |x|\le t, c=0 on |x|\ge2t, and |\nabla c|^2+|\nabla o|^2\le C t^{-2} supported in the intervening annulus. Let X be its full out data and set q^c=Z-n_c, where n_c is the number of core particles. Since n_c\le\#\{i:|x_i|<2t\}, we have \E q^c>1.

We first show that the favorable event G=\{n_c\le Z-1\} has probability bounded below independently of Z. Independently of the cut labels, observe one unordered array with the smooth compact noise law of Lemma 5.2, choosing its fixed width so that each spatial displacement is less than t/8. Put

q^{\rm obs}=Z-\#\{\text{array entries in }B(0,t/2)\}.

Every entry counted here comes from a particle of radius less than 5t/8, which must be core. Thus q^c\le q^{\rm obs} on the enlarged probability space. Conversely every particle of radius less than t/4 produces an entry in B(0,t/2).

For an event A_\lambda=\{q^{\rm obs}>\lambda\} of probability p>0, the single-array version of (5.4) produces a normalized state \Psi_{A_\lambda} whose raw configuration law is the law conditioned on that event and whose offset satisfies

\delta\le C_t\log^5(e/p).

Every compatible configuration obeys Z-\#\{|x_i|<t/4\}>\lambda. Hence Lemma 12.2 gives

\lambda\le C_t\big(1+\log^{5/2}(e/p)\big).

For sufficiently large \lambda this implies p\le e\exp(-c_t\lambda^{2/5}); the inequality is also harmless when p=0. Integrating the tail yields

\E(q^c)_+^2\le\E(q^{\rm obs})_+^2\le C_t, \qquad \Prob(G)=\Prob(q^c>0) \ge\frac{(\E(q^c)_+)^2}{\E(q^c)_+^2}\ge c_t>0. \tag{12.8}

Here the equality of events uses the integer-valued core count, and \E(q^c)_+\ge\E q^c>1.

We next estimate the average energy of the core slices. The localization error is O_t(1) by (4.45) at offset zero. In the attractive term of (3.6), retain only the core repulsion from particles with radius less than t/4, which are core with probability one. Conditional integration followed by averaging the original cut labels gives

\E\sum_{i\ {\rm out}}\Phi_X(x_i) \le\E_{\Psi_*}\sum_i o(x_i)^2 B_{t/4}(x_i). \tag{12.9}

This comparison of expectations uses the raw inner particles; it does not identify fields from different core slices.

Divide the nonzero terms on the right into shells u\le|x_i|<2u, u=2^\ell t, \ell\ge0. For each shell use an auxiliary cut of the original state, full out on that shell, supported in u/2<|x|<4u, with gradient cost C u^{-2}, and call its data Y. All weighted shell positions and their weights o(x_i)^2 are then recorded. Conditional integration of the raw field, with the harmonic version of Lemma 12.1, bounds the shell expectation by \E[n_u M(Y)], where n_u=\#\{u\le|x_i|<2u\}. Equations (4.45) and (12.4) give

\E[n_uM]\le\|n_u\|_2\|M\|_2 \le C_t\frac{1+\ell}{2^\ell t}.

The constants are independent of the shell index and this series is summable. For each fixed system the original attraction and repulsion expectations are finite by the form bounds, so the shell decomposition is legitimate; alternatively one can first use finitely many shells and pass to the limit. Dropping the nonnegative out kinetic energy and out–out repulsion from (3.6), and using (12.9), now proves

0\le\E(e_X-E)\le C_t. \tag{12.10}

Every slice satisfies e_X\ge E, and on G sector monotonicity gives e_X\ge E_{n_c}\ge E_{Z-1}. Therefore

c_t(E_{Z-1}-E) \le\Prob(G)(E_{Z-1}-E) \le\E(e_X-E)\le C_t,

which proves (12.7). This argument has used only the zero-offset ground state and the general-offset screening estimates; no neutral offset or ionization gap was assumed.

By monotonicity, E_Z\le E_{Z-1}\le E+C. We may consequently apply Proposition 11.1 again, now with this fixed value of D_0, to every normalized neutral ground state. There are universal s_*>0 and Z_1 such that

\int_{|x|\ge s_*}\rho_{\Psi_Z}(x)\,\dd x>\frac12 \qquad (Z\ge Z_1). \tag{12.11}

In fact the deficit proposition gives a tail greater than one at an appropriate such radius. Absolute continuity of the density makes the choice between strict and non-strict radial endpoints immaterial.

13 A uniform positive ionization gap

The energy bound of Section 12 makes a distant insertion trial effective in every singly ionized atom. Averaging the insertion center recovers its unit unscreened charge; a complementary localized state controls the attraction lost when a hole is made for the orbital.

Proposition 13.1 (Positive ionization energy). There are universal constants c>0 and Z_2<\infty such that

E_{Z-1}-E_Z\ge c\qquad(Z\ge Z_2). \tag{13.1}

Proof. For Z\ge\max(Z_0,2), take a normalized ground state \Phi of H_{Z-1,Z}. It exists by Lemma 2.5, and its offset from E is bounded by Proposition 12.3. In this proof S\ge1 will be a large universal constant, fixed at the end, and b=S^{3/5}. Angle brackets denote normalized Lebesgue averaging over the centers \mathcal A_S=\{y:S\le|y|\le2S\}.

Use the real normalized radial packet g_b from Section 3. Choose smooth real functions c_y,o_y with c_y^2+o_y^2=1, c_y=0 on B(y,2b), c_y=1 outside B(y,3b), and

|\nabla c_y|^2+|\nabla o_y|^2 \le Cb^{-2}\1_{B(y,3b)}.

Set

F_y=\prod_{i=1}^{Z-1}c_y(x_i),\quad n_y^{\rm near}=\#\{i:|x_i-y|<3b\},\quad N_y=\E_\Phi n_y^{\rm near},\quad A_y=\E_\Phi F_y^2.

The unnormalized core F_y\Phi has no particles in B(y,2b). Wedge this core with the normalized one-spin orbital g_b(\cdot-y); the resulting unnormalized Z-electron vector has squared norm A_y. Spatial separation makes the terms assigning different particle labels to the two groups orthogonal. It also makes its energy equal to the core energy, plus the orbital energy times A_y, plus the direct cross repulsion. In particular, with the raw-configuration field

H_y^{\rm add} =\int g_b(x-y)^2 \left(V(x)-\sum_{i=1}^{Z-1}K(x-x_i)\right)\,\dd x,

the multiplier identity (2.4) and the variational principle give

\begin{align*} (E_Z-E_{Z-1})A_y &\le \frac12\E_\Phi|\nabla F_y|^2 +\frac{\|\nabla g\|_2^2}{2b^2}A_y -\E_\Phi[F_y^2H_y^{\rm add}]\\ &\le Cb^{-2}(1+N_y)-\E_\Phi[F_y^2H_y^{\rm add}]. \tag{13.2}\end{align*}

This inequality also holds if A_y=0, since its derivation uses the unnormalized trial and its zero norm.

For every raw configuration, averaging the full insertion field gives

\langle H_y^{\rm add}\rangle\ge\frac1{2S}. \tag{13.3}

To verify this without a symmetry assumption on \Phi, fix the center radius r\in[S,2S]. The nuclear packet average is Z/r since b<r. For any fixed electron position z, the spherical average in y of its packet potential is

\int g_b(v)^2\frac1{\max(r,|z-v|)}\,\dd v\le\frac1r.

This follows by first averaging K(y+v-z) over |y|=r and then integrating v. There are Z-1 electrons, so the averaged field is at least 1/r\ge1/(2S). Radial averaging proves (13.3).

The mean number of particles near a proposed center is small. For large S, 3b<S/2, and a particle can lie in B(y,3b) for some y\in\mathcal A_S only if S/2\le|x_i|\le3S. The fraction of such centers for any particle is at most Cb^3/S^3. Fubini and (4.45), with the bounded offset of \Phi, yield

\langle N_y\rangle \le C(b/S)^3\E_\Phi\#\{i:S/2\le|x_i|\le3S\} \le C(b/S)^3(1+\sqrt S) \le CS^{-7/10}. \tag{13.4}

Writing p_y=1-A_y=\E_\Phi(1-F_y^2), the product inequality 1-\prod_i c_y(x_i)^2\le\sum_i(1-c_y(x_i)^2) gives p_y\le N_y.

It remains to bound the potentially positive field lost on the discarded configurations. The symmetric multiplier G_y=\sqrt{1-F_y^2} is Lipschitz, even where it vanishes, and

|\nabla G_y|^2\le Cb^{-2}n_y^{\rm near}. \tag{13.5}

For a direct justification, take all products of c_y and o_y in the particle variables except the all-core product. Their Euclidean norm is G_y. The squared gradient of a norm is bounded by the sum of the squared gradients of its components; the full product partition has squared gradient sum \sum_i(|\nabla c_y|^2+|\nabla o_y|^2)(x_i). This proves (13.5) and the stated Lipschitz property.

If p_y>0, put \Phi_y^{\rm loss}=G_y\Phi/\sqrt{p_y}. This is a normalized antisymmetric form-domain vector. By (2.4), (12.7), and (13.5), its offset satisfies

\delta_y\le C+Cb^{-2}N_y/p_y. \tag{13.6}

Choose S large enough also that b<A S/L. At each center y in the annulus, the nucleus and every electron included in J_y lie outside the radial packet. Their packet averages equal their point potentials at y. All omitted electron terms enter with a negative sign, whence H_y^{\rm add}\le J_y pointwise in the configuration. Using (4.39) with no initial cut, now in the state \Phi_y^{\rm loss}, gives

\begin{align*} \E_\Phi[(1-F_y^2)H_y^{\rm add}] &=p_y\E_{\Phi_y^{\rm loss}}H_y^{\rm add}\\ &\le Cp_y\big(S^{-1}+\sqrt{\delta_y}\,S^{-1/2}\big)\\ &\le C\left[ p_y(S^{-1}+S^{-1/2}) +b^{-1}S^{-1/2}\sqrt{p_yN_y}\right]. \tag{13.7}\end{align*}

Here we may assume S/L\ge1; L is fixed. If p_y=0, the left side is zero and the same bound holds. All expectations in this calculation are finite for a fixed system by the form bounds (the packet potential is bounded as well).

Since p_y\le N_y, (13.4) implies

\left\langle\E_\Phi[(1-F_y^2)H_y^{\rm add}]\right\rangle \le C\left(S^{-17/10}+S^{-6/5}+S^{-9/5}\right) =o(S^{-1}).

Also

Cb^{-2}(1+\langle N_y\rangle) \le C(S^{-6/5}+S^{-19/10})=o(S^{-1}).

These estimates explain the width choice: any b=S^a with 1/2<a<2/3 would make the kinetic term and the largest averaged field loss smaller than S^{-1}. All these limits are uniform in Z and in the ground state \Phi. Average (13.2) and write F_y^2H_y^{\rm add}=H_y^{\rm add}-(1-F_y^2)H_y^{\rm add}. Equations (13.3) and (13.7) then show, for one sufficiently large universal choice of S,

(E_Z-E_{Z-1})\langle A_y\rangle\le-\frac1{4S}.

In particular \langle A_y\rangle>0. As it is at most one, dividing gives E_{Z-1}-E_Z\ge1/(4S). This proves (13.1).

Proof of Corollary 1.3. In the notation E_Z(n)=E(n,Z) of the corollary, Proposition 12.3 gives universal C_0,Z_0<\infty such that, for Z\ge Z_0,

I_1(Z)=E_Z(Z-1)-E_Z(Z) \le E_Z(Z-1)-\inf_{n\ge0}E_Z(n)\le C_0.

The first inequality uses \inf_{n\ge0}E_Z(n)\le E_Z(Z). Proposition 13.1 gives universal c_0>0 and Z_2<\infty such that I_1(Z)\ge c_0 for Z\ge Z_2.

Choose an integer Z_*\ge\max\{2,Z_0,Z_2\}. For each integer 1\le Z<Z_*, the finite-sector Coulomb forms are bounded below and admit finite-energy trial states, so E_Z(Z-1) and E_Z(Z) are finite; the vacuum energy is E_Z(0)=0. Lemma 2.5, applied with n=Z, gives I_1(Z)>0. Thus all the finitely many remaining gaps lie in (0,\infty). Set

c=\min\{c_0,I_1(1),\ldots,I_1(Z_*-1)\}, \qquad C=\max\{C_0,I_1(1),\ldots,I_1(Z_*-1)\}.

These constants satisfy 0<c\le C<\infty. They are universal because Z_* is universal and the exceptional gaps belong to finitely many atoms in the fixed normalization. The large-Z bounds and these choices prove the assertion for every integer Z\ge1.

14 The outer tail and the half-electron radius

We now combine the positive ionization gap with a weighted shell estimate. The conditional field is estimated after changing the law by the shell mass itself; the measurability of this mass in the cut data is what avoids an additional particle-count factor.

Proposition 14.1 (Uniform exterior mass). There exist universal C,R_0,Z_3<\infty such that every normalized neutral ground state with Z\ge Z_3 satisfies

\int_{|x|>R}\rho_{\Psi_Z}(x)\,\dd x\le\frac C R \qquad(R\ge R_0). \tag{14.1}

Proof. Fix any such ground state \Psi=\Psi_Z and write \E for its raw configuration expectation. By Proposition 12.3 its offset is bounded by a universal constant, and by Proposition 13.1 its ionization gap is at least c>0. For u\ge1, choose a smooth radial cutoff \chi_u(r)=\chi(r/u), where 0\le\chi\le1, \chi=1 on [1,2], and \chi is supported in [1/2,4]. Put

\begin{gathered} w_i=\chi_u(|x_i|)^2,\qquad S_u=\sum_{i=1}^Z w_i,\qquad m_u=\E S_u,\\ n_{\rm adj}=\#\{i:u/2\le|x_i|\le4u\},\qquad N_u=\E n_{\rm adj}. \end{gathered}

In particular m_u\le N_u. Define

\mathcal B_u(x)=V(x)-\sum_{|x_j|<u/8}K(x-x_j) =B_{u/8}(x).

Only its values on the support of \chi_u will be used, so the selected electron never occurs among these inner sources.

Testing the weak eigen-equation by S_u\Psi, and decomposing the result into its i-th weighted terms, gives a useful lower bound. For fixed x_i and spin, the other Z-1 variables are antisymmetric; their energy is at least E_{Z-1} times their squared norm. The selected electron’s kinetic pairing is

\operatorname{Re}\frac12\int \nabla_i\overline\Psi\cdot\nabla_i(w_i\Psi) =\frac12\int w_i|\nabla_i\Psi|^2 -\frac14\int(\Delta_iw_i)|\Psi|^2 \ge-Cu^{-2}\E\1_{\{u/2\le|x_i|\le4u\}}.

The integration by parts follows first for smooth form approximants; w_i and its first two derivatives are bounded, so it passes to the form domain. Keeping only the selected electron’s repulsion from inner sources, and discarding its other nonnegative pair terms, therefore gives

c m_u\le C u^{-2}N_u +\E\sum_i w_i \mathcal B_u(x_i). \tag{14.2}

Suppose first that m_u>0. The normalized antisymmetric state

\Psi_u^*=\sqrt{S_u/m_u}\,\Psi

is form admissible. Indeed \sqrt{S_u} is the Euclidean norm of the vector (\chi_u(|x_i|))_i, hence is Lipschitz. Where S_u>0,

|\nabla\sqrt{S_u}|^2 =\frac{\sum_i\chi_u(|x_i|)^2|\nabla_i\chi_u(|x_i|)|^2}{S_u} \le C u^{-2};

its gradient vanishes almost everywhere on its zero set. In particular this is bounded by Cu^{-2}n_{\rm adj}. Identity (2.4) shows that its offset satisfies

\delta_u\le C+Cu^{-2}N_u/m_u<\infty. \tag{14.3}

There is no assumed positive lower bound on m_u.

We reveal every position carrying a positive shell weight so that S_u is determined by the data. Use an auxiliary cut which is full out on u/2\le|x|\le4u, supported in u/4<|x|<8u, and has squared gradient cost at most Cu^{-2}. Let \omega denote the raw configuration, let \ell denote these cut labels, and let Y=Y(\omega,\ell) be all recorded out data. If Q(\dd\ell\mid\omega) is the conditional label kernel, use exactly this kernel for both states. Their joint laws are then

\begin{split} P(\dd\omega,\dd\ell) &=|\Psi(\omega)|^2\,\dd\omega\,Q(\dd\ell\mid\omega),\\ P^*(\dd\omega,\dd\ell) &=\frac{S_u(\omega)}{m_u}\,P(\dd\omega,\dd\ell). \end{split} \tag{14.4}

Integration in \omega includes the spin sum. Every particle with positive w_i is recorded by this cut, so

S_u(\omega)=s(Y):= \sum_{i\ {\rm recorded}}\chi_u(|x_i|)^2.

This equality includes the random labels in the transition regions: particles there have weight zero. It follows from (14.4) that

\frac{\dd P_Y^*}{\dd P_Y}=\frac{s(Y)}{m_u},\qquad \E_{P^*}[F\mid Y]=\E_P[F\mid Y]\quad\text{on }\{s>0\} \tag{14.5}

for every bounded measurable F, and then for integrable F by truncation wherever the conditional expectations are defined. For example, multiply the asserted equality by s(Y) and integrate over an arbitrary data event to check it directly. At the slice level the same fact says that \sqrt{S_u/m_u} is constant in the surviving core variables and cancels when their wavefunction is normalized. The set s=0 has zero P^*-mass and contributes nothing to the original weighted sum.

Let

h_Y(x)=\E_P[\mathcal B_u(x)\mid Y],\qquad M(Y)=\sup_{u/2\le|x|\le4u}(h_Y(x))_+.

On the broad annulus u/4<|x|<6u all the inner sources are separated from the evaluation point. Lemma 12.1 supplies continuous harmonic versions of these fields. Applying (14.5) first at a countable dense set of points and then using continuity makes the conditional fields for P and P^* equal on the entire broad annulus, outside one data-null set on \{s>0\}. The two data laws are equivalent on that set. Thus the equality applies at recorded random positions as well as to the positive supremum.

Use (12.5) in the state \Psi_u^*. It gives

\|M\|_{L^2(P^*)} \le C\big(u^{-1}+\sqrt{\delta_u}\,u^{-1/2}\big). \tag{14.6}

This is an application of the screening estimate for arbitrary finite offsets, not of its small-offset refinement. In particular the cut condition is uniform even if m_u is very small: as checked in Lemma 12.1, its cell coefficients obey D_z^2/(a_zm_z)\le C for every \delta_u, because a_zm_z\ge1.

To see explicitly how the weighted count is used, introduce the data-measurable measure

\eta_Y=\sum_{i\ {\rm recorded}}w_i\delta_{x_i}, \qquad \eta_Y(\R^3)=s(Y).

Conditional integration and (14.4) now yield

\begin{align*} \E\sum_iw_i\mathcal B_u(x_i) &=\E_P\int h_Y\,\dd\eta_Y\\ &=m_u\E_{P^*} \left[\frac1{s(Y)}\int h_Y\,\dd\eta_Y\right]\\ &\le m_u\E_{P^*}M \le C m_u\big(u^{-1}+\sqrt{\delta_u}\,u^{-1/2}\big). \tag{14.7}\end{align*}

The quotient may be defined as zero on s=0. This exact change of measure accounts for all shell weights, so there is no further particle-count factor in the last bound.

Substituting (14.3) into (14.7), and then into (14.2), gives

\begin{align*} c m_u &\le Cu^{-2}N_u +Cm_u(u^{-1}+u^{-1/2}) +Cu^{-3/2}\sqrt{m_uN_u}\\ &\le C(u^{-2}+u^{-3/2})N_u +Cm_u(u^{-1}+u^{-1/2}).\end{align*}

The second line uses m_u\le N_u. When m_u=0 it holds trivially without introducing a biased law. For all sufficiently large u, absorb the last term into the left side. Applying (4.45) in the original state, whose offset is uniformly bounded, gives N_u\le C(1+\sqrt u) and hence

\E\#\{i:u\le|x_i|\le2u\}\le m_u\le C/u. \tag{14.8}

Finally, sum over u=2^jR, j\ge0. The density gives zero mass to the intervening spheres, and \sum_{j\ge0}(2^jR)^{-1}=2/R. This proves (14.1).

Completion of the proof of Theorem 1.2. For all sufficiently large Z, (12.11) supplies a fixed s_*>0 for which the exterior mass exceeds 1/2. Monotonicity of that mass as a function of the radius implies R(\Psi_Z)\ge s_*. Proposition 14.1 supplies a fixed large R_* for which the exterior mass is at most 1/2, and hence R(\Psi_Z)\le R_*.

For clarity we give uniform arguments over the entire ground-state space for each of the finitely many remaining charges. Fix such a Z. The strict gap E_Z<E_{Z-1} and the compactness conclusion in Lemma 2.5 show that every sequence of normalized neutral ground states has a strongly L^2 convergent subsequence. In particular their configuration laws are uniformly tight. To see directly why compactness gives the required uniform tail, suppose otherwise and choose radii R_k\to\infty and normalized ground states \Psi_k with

\int_{|x|>R_k}\rho_{\Psi_k}(x)\,\dd x>\frac12.

After a subsequence \Psi_k\to\Psi strongly in L^2. The bounded multiplication operator \sum_i\1_{\{|x_i|>R_k\}} has norm at most Z, so its expectations in \Psi_k and \Psi differ by at most 2Z\|\Psi_k-\Psi\|_2. Its expectation in the fixed \Psi tends to zero by dominated convergence, a contradiction. Thus a finite upper radius works uniformly for this Z.

For the lower bound, the kinetic estimate (3.3), with the fixed finite offset E_Z-E, gives

\int\rho_{\Psi_Z}^{5/3}\le C_Z

uniformly over its normalized ground states. Hölder’s inequality therefore yields

\int_{|x|<r}\rho_{\Psi_Z}(x)\,\dd x \le |B(0,r)|^{2/5} \left(\int\rho_{\Psi_Z}^{5/3}\right)^{3/5} \le C_Z r^{6/5}.

Choose a positive r_Z making this less than Z-1/2. The exterior mass then exceeds 1/2, uniformly over the ground states, so R(\Psi_Z)\ge r_Z.

Taking the minimum of s_* and these finitely many positive lower radii, and the maximum of R_* and the finitely many upper radii, gives universal 0<c\le C<\infty. All density measures used above are absolutely continuous. Their exterior masses are consequently continuous in the radius, start at Z, and tend to zero. Thus the infimum defining the half-electron radius has the stated bounds for every normalized neutral ground state, as required.

15 Interfaces for atomic asymptotics

The estimates used in questions about ionization energies and outer radii have different offset requirements. We collect their precise scope here; the complete proofs are in the preceding sections.

Arbitrary energy offsets. For a finite-sector state of energy at most E+\delta, the exact cut identity, coherent insertion, and fine-density lower bounds are Lemmas 3.4, 3.5, and 3.6. In atomic distance geometry, Proposition 4.5 and Corollary 4.9 allow every finite \delta\ge0; their count unit is \max(a^{-3},1)+\sqrt{\delta a}. For sectors n\le3Z, Lemma 12.1 keeps this dependence in its complete convergent series for conditional inner fields. The fine comparison Lemma 4.6 has the additional restriction \delta\le a^{-7+.02}. These are distinct assertions.

Events of a sector ground state. For a ground state of energy E_n, Lemma 5.2 bounds the cost above E_n by C\ell_j^{-2}\log^5(e/p), independent of the number of particles or arrays. The offset above E is therefore E_n-E+C\ell_j^{-2}\log^5(e/p). This exact baseline dependence is available when the offset grows. The fixed-offset comparison Proposition 10.1, by contrast, first fixes a finite D_0\ge E_n-E, then takes s sufficiently small according to D_0 and the stated band and accuracy parameters. It is not a uniform comparison at arbitrary growing D_0.

Common observations and intermediate fields. The master-kernel formula and its universal constants in (10.2) do not depend on the inverse-comparison heights or accuracy. To use several comparisons with the same conditional density and field, choose s to satisfy all their corresponding smallness conditions in Proposition 10.1, then fix the resulting packet widths and observation arrays. This applies to any collection admitting such a common s; for finitely many fixed requests, the minimum of their thresholds suffices. Proposition 11.2 uses exactly these packets at every intermediate index; its error bound (11.3) is in expectation before the last array is forgotten. Its differential inequality holds globally after cancellation of the nuclear singularity, its lower barrier persists at every index, and its exterior equality holds beyond L_1r_j. The construction may be stopped at any prefix without changing the master smoothing.

Classical comparison and the neutral offset. The Thomas–Fermi minimizer and point-source comparison required for coefficient identification are Lemmas 7.1 and 7.2, valid for every positive real point charge. The quantum offset needed for neutral states is Proposition 12.3. It follows from zero-offset deletion and is uniform over all neutral ground states by sector monotonicity. These are independent inputs: the excess-charge conclusion itself does not replace either the Thomas–Fermi estimates or the neutral-sector argument.

References

  1. [1]R. Benguria and Elliott H. Lieb. The most negative ion in the Thomas–Fermi–von Weizsäcker theory of atoms and molecules. Journal of Physics B: Atomic and Molecular Physics, 18(6):1045–1059, 1985. doi:10.1088/0022-3700/18/6/006.
  2. [2]Charles L. Fefferman and Luis A. Seco. Asymptotic neutrality of large ions. Communications in Mathematical Physics, 128(1):109–130, 1990. doi:10.1007/BF02097048.
  3. [3]Enrico Fermi. Un metodo statistico per la determinazione di alcune proprietà dell’atomo. Rendiconti dell’Accademia Nazionale dei Lincei, 6:602–607, 1927.
  4. [4]Dirk Hundertmark, Nikolaos Pattakos, and Marvin Raimund Schulz. On the Excess Charge Problem of Atoms. 2025. Version 1, 25 April 2025. doi:10.48550/arXiv.2504.18487, arXiv:2504.18487.
  5. [5]Victor Ivrii. Asymptotics of the ground state energy of heavy molecules and related topics. 2012. arXiv:1210.1132v2, 28 March 2017. arXiv:1210.1132.
  6. [6]Mathieu Lewin. Geometric methods for nonlinear many-body quantum systems. Journal of Functional Analysis, 260(12):3535–3595, 2011. doi:10.1016/j.jfa.2010.11.017, arXiv:1009.2836.
  7. [7]Mathieu Lewin. Some open mathematical problems concerning charged quantum particles. Comptes Rendus. Physique, 26:369–380, 2025. doi:10.5802/crphys.249.
  8. [8]Elliott H. Lieb. Bound on the maximum negative ionization of atoms and molecules. Physical Review A, 29(6):3018–3028, 1984. doi:10.1103/PhysRevA.29.3018.
  9. [9]Elliott H. Lieb, Israel M. Sigal, Barry Simon, and Walter Thirring. Asymptotic Neutrality of Large-Z Ions. Physical Review Letters, 52(12):994–996, 1984. doi:10.1103/PhysRevLett.52.994.
  10. [10]Elliott H. Lieb, Israel M. Sigal, Barry Simon, and Walter Thirring. Approximate neutrality of large-Z ions. Communications in Mathematical Physics, 116(4):635–644, 1988. doi:10.1007/BF01224904.
  11. [11]Elliott H. Lieb and Barry Simon. Thomas–Fermi Theory Revisited. Physical Review Letters, 31(11):681–683, 1973. doi:10.1103/PhysRevLett.31.681.
  12. [12]Elliott H. Lieb and Barry Simon. The Thomas–Fermi theory of atoms, molecules and solids. Advances in Mathematics, 23(1):22–116, 1977. doi:10.1016/0001-8708(77)90108-6.
  13. [13]Elliott H. Lieb and Walter E. Thirring. Bound for the Kinetic Energy of Fermions Which Proves the Stability of Matter. Physical Review Letters, 35(11):687–689, 1975. Erratum: Physical Review Letters 35 (1975), 1116. doi:10.1103/PhysRevLett.35.687.
  14. [14]Phan Thành Nam. New Bounds on the Maximum Ionization of Atoms. Communications in Mathematical Physics, 312(2):427–445, 2012. doi:10.1007/s00220-012-1479-y, arXiv:1009.2367.
  15. [15]OpenAI. Generalized ionization energies for full Coulomb atoms. OpenAI Math Release preprint PDF, 2026. Reading view on this site: Generalized ionization energies for full Coulomb atoms.
  16. [16]OpenAI. Generalized outer-electron radii of neutral Coulomb atoms. OpenAI Math Release preprint PDF, 2026. Reading view on this site: Generalized outer-electron radii of neutral Coulomb atoms.
  17. [17]Michel Rumin. Balanced distribution-energy inequalities and related entropy bounds. Duke Mathematical Journal, 160(3):567–597, 2011. doi:10.1215/00127094-1444305, arXiv:1008.1674.
  18. [18]Luis A. Seco, Israel M. Sigal, and Jan Philip Solovej. Bound on the ionization energy of large atoms. Communications in Mathematical Physics, 131(2):307–315, 1990. doi:10.1007/BF02161416.
  19. [19]Barry Simon. Schrödinger operators in the twenty-first century. In A. Fokas, A. Grigoryan, T. Kibble, and B. Zegarlinski, editors, Mathematical Physics 2000, pages 283–288, Imperial College Press, 2000. doi:10.1142/9781848160224_0014.
  20. [20]Jan Philip Solovej. Proof of the ionization conjecture in a reduced Hartree–Fock model. Inventiones mathematicae, 104:291–311, 1991. doi:10.1007/BF01245077.
  21. [21]Jan Philip Solovej. The ionization conjecture in Hartree–Fock theory. Annals of Mathematics, 158(2):509–576, 2003. doi:10.4007/annals.2003.158.509, arXiv:math-ph/0012026.
  22. [22]Jan Philip Solovej. A new look at Thomas–Fermi theory. Molecular Physics, 114(7–8):1036–1040, 2016. doi:10.1080/00268976.2015.1130273, arXiv:1601.00497.
  23. [23]L. H. Thomas. The calculation of atomic fields. Proceedings of the Cambridge Philosophical Society, 23(5):542–548, 1927. doi:10.1017/S0305004100011683.
  24. [24]G. M. Zhislin. A study of the spectrum of the Schrödinger operator for a system of several particles. Trudy Moskovskogo Matematicheskogo Obshchestva, 9:81–120, 1960. Erratum: volume 10 (1961), 437. https://www.mathnet.ru/eng/mmo97.
  25. [25]G. M. Zhislin and A. G. Sigalov. The spectrum of the energy operator for atoms with fixed nuclei on subspaces corresponding to irreducible representations of the group of permutations. Izvestiya Akademii Nauk SSSR. Seriya Matematicheskaya, 29(4):835–860, 1965. https://www.mathnet.ru/eng/im3076.