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Shadow Theory

Section 10 9 October 2026

The actual compact-profile electron–source parent

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10 The actual compact-profile electron–source parent

Choose a real radial cutoff with χR=1\chi_R=1 for ∣r∣≤R|r|\leq R, χR=0\chi_R=0 for ∣r∣≥R+1|r|\geq R+1, 0≤χR≤10\leq\chi_R\leq1 and ∣χR′∣≤8|\chi_R'|\leq8. Such a smooth flat cutoff is explicit: on 0<t<10<t<1 use

χR(R+t)=1−e−1/te−1/t+e−1/(1−t). \chi_R(R+t)=1- \frac{e^{-1/t}}{e^{-1/t}+e^{-1/(1-t)}}.

For t≤1/2t\leq1/2 its derivative is bounded by e2−1/t(t−2+4)≤8e^{2-1/t}(t^{-2}+4)\leq8; reflection treats the other half. Set

dR(r)=rzχR(∣r∣),d0=∥dR∥∞≤R+1,H=h+Hs+gYdR, d_R(r)=r_z\chi_R(|r|),\quad d_0=\|d_R\|_\infty\leq R+1,\qquad H=h+H_s+gYd_R , (10.1)

with real constant gg. This is a prescribed compact-profile scalar parent. The finite annular electrostatic density −ϵ0ΔdR-\epsilon_0\Delta d_R does not by itself construct its quantized source, field energy or laboratory realization.

Lemma 10.1 (Physical domains and forcing tail)

The parent (10.1) is self-adjoint on D(h)∩D(Hs)D(h)\cap D(H_s) and has form domain H1(R3×R)∩{Yψ∈L2}H^1(\mathbb R^3\times\mathbb R)\cap\{Y\psi\in L^2\}. It satisfies

H+2+g2d02Ω≥I+14pr2+12Hs. H+2+\frac{g^2d_0^2}{\Omega} \geq I+\tfrac14p_r^2+\tfrac12H_s . (10.2)

For fR=dRϕf_R=d_R\phi and R≥40R\geq40,

∥fR−f∥2≤ϵR2:=e−2R(23R4+43R3+2R2+2R+1),∥(h+1)1/2(fR−f)∥≤41.5+R−2 ϵR.\begin{align}\|f_R-f\|^2&\leq\epsilon_R^2:= e^{-2R}\left(\tfrac23R^4+\tfrac43R^3+2R^2+2R+1\right), \tag{10.3}\\ \|(h+1)^{1/2}(f_R-f)\| &\leq\sqrt{41.5+R^{-2}}\,\epsilon_R . \tag{10.4}\end{align}

At R=40R=40 these upper bounds are respectively 6⋅10−156\cdot10^{-15} in norm and 4⋅10−144\cdot10^{-14} in first-form norm.

Proof

Hardy and interpolation make Coulomb infinitesimally Laplacian bounded. The independent electron and oscillator operators commute; after a common positive shift their sum has domain D(h)∩D(Hs)D(h)\cap D(H_s). Since ∥Yψ∥≤2/Ω∥Hs1/2ψ∥\|Y\psi\|\leq\sqrt{2/\Omega}\|H_s^{1/2}\psi\| and dRd_R is bounded, gYdRgYd_R is infinitesimally operator bounded relative to this sum. This proves the operator assertion and the corresponding common closed form.

The square 14∥∇u+2r^ u∥2≥0\frac14\|\nabla u+2\widehat r\,u\|^2\geq0 gives h+1≥pr2/4h+1\geq p_r^2/4. Young's inequality gives gYdR≥−ΩY2/4−g2d02/ΩgYd_R\geq-\Omega Y^2/4-g^2d_0^2/\Omega and Hs−ΩY2/4≥Hs/2H_s-\Omega Y^2/4\geq H_s/2, proving (10.2).

The omitted forcing is confined to r≥Rr\geq R and has magnitude at most that of ufu_f. Integrating (4/3)r4e−2r(4/3)r^4e^{-2r} gives (10.3). For the radial error w=(χR−1)ufw=(\chi_R-1)u_f, ∣uf′∣≤uf|u_f'|\leq u_f on this tail and therefore ∣w′∣≤9uf|w'|\leq9u_f. The positive upper bound on the remaining radial form potential is 1+r−21+r^{-2}. Thus

⟨w,(h1+1)w⟩≤(812+1+R−2)∫R∞∣uf∣2 dr, \langle w,(h_1+1)w\rangle \leq\left(\tfrac{81}2+1+R^{-2}\right) \int_R^\infty|u_f|^2\,dr,

which is (10.4). Reciprocal positive Taylor sums for e80e^{80} enclose the stated numerical tails.

□

The cutoff is essential to the actual source parent. With an uncut gYrzgYr_z, completing the source square leaves −g2rz2/(2Ω)-g^2r_z^2/(2\Omega). Electron packets translated to rz=Lr_z=L and source packets translated to Y=−gL/ΩY=-gL/\Omega have energy tending to −∞-\infty. Thus no stable uncut source Hamiltonian is being approximated here. Equations (10.3)–(10.4) compare forcing vectors, not complete actual parents.

10.1 Exact blocks, including source feedback

Let

P=∣ϕ⟩⟨ϕ∣⊗I,Q=I−P,Ψ=ϕp+q,q=QΨ. P=|\phi\rangle\langle\phi|\otimes I,\qquad Q=I-P,\qquad \Psi=\phi p+q,\quad q=Q\Psi .

The projection PP does not reduce HH. The odd profile has PdRP=0Pd_RP=0, so the exact equations are

iq˙=Aq+Lp,A=QHQ,Lp=gfR⊗Yp,ip˙=(Hs−12)p+gY⟨ϕ,dRq⟩r.\begin{align}i\dot q&=Aq+Lp,& A&=QHQ,& Lp&=gf_R\otimes Yp, \tag{10.5}\\ i\dot p&=(H_s-\tfrac12)p+ gY\langle\phi,d_Rq\rangle_r . \tag{10.6}\end{align}

The subscript on the last inner product means integration in the electron coordinate only. The actual vector p(Y,t)p(Y,t) retains its source phase and every finite internal coefficient. It is not prescribed as a free source waveform.

On QQ put

A0=Q(h+Hs)Q,K0=A0+1,K=A+1,Tph=I+12pr2+Hs. A_0=Q(h+H_s)Q,\qquad K_0=A_0+1,\qquad K=A+1,\qquad T_{\rm ph}=I+\tfrac12p_r^2+H_s . (10.7)

Here A0A_0 is the self-adjoint restriction of h+Hsh+H_s to QHQ\mathcal H. The spectral projection QQ preserves the common operator and form domains. More precisely, AA denotes the self-adjoint operator A0+gYQdRQA_0+gYQd_RQ on D(A0)D(A_0): the electronic factor QdRQQd_RQ is bounded and commutes with the source coordinate, so the same infinitesimal relative-bound argument used in Lemma 10.1 applies. Thus QHQQHQ denotes this proved realization, rather than an assumed self-adjoint compression.

Since the complete excited electronic floor is −1/8-1/8,

K0≥7/8+Hs,K0≥pr2/4+Hs,Tph≤(22/7)K0. K_0\geq7/8+H_s,\qquad K_0\geq p_r^2/4+H_s,\qquad T_{\rm ph}\leq(22/7)K_0 . (10.8)

For the last inequality take 4/114/11 of the first lower bound and 7/117/11 of the second, then multiply by 22/722/7. This gives the exact coefficients 11 and 1/21/2 of the identity and electron kinetic terms; the source coefficient is larger than required.

The unbounded source interaction has the bounded form sandwich

∥K0−1/2gYQdRQK0−1/2∥≤θ:=∣g∣d02Ω(7/8). \|K_0^{-1/2}gYQd_RQK_0^{-1/2}\| \leq\theta:=|g|d_0\sqrt{\frac{2}{\Omega(7/8)}}. (10.9)

Indeed use ∥u∥≤(7/8)−1/2∥K01/2u∥\|u\|\leq(7/8)^{-1/2}\|K_0^{1/2}u\| on one factor, and ∥Yv∥≤2/Ω∥K01/2v∥\|Yv\|\leq\sqrt{2/\Omega}\|K_0^{1/2}v\| on the other. This bounds the full sesquilinear form and hence its operator. If θ<1\theta<1, then

(1−θ)K0≤K≤(1+θ)K0. (1-\theta)K_0\leq K\leq(1+\theta)K_0 . (10.10)

All these inequalities are physical form inequalities on the complete QQ space. They neither truncate the oscillator nor delete QYdRQQYd_RQ.

10.2 The spectral supremum and its correction

For ζ=E+iη\zeta=E+i\eta, η>0\eta>0, the spectral theorem gives

Jspec(E,η):=∥K01/2(A0−ζ)−1K01/2∥=sup⁡a∈σ(A0)a+1∣a−ζ∣≤J‾(E,η):=sup⁡a≥−1/8+Ω/2a+1∣a−ζ∣.\begin{align}J_{\rm spec}(E,\eta) &:=\|K_0^{1/2}(A_0-\zeta)^{-1}K_0^{1/2}\| =\sup_{a\in\sigma(A_0)}\frac{a+1}{|a-\zeta|} \notag\\ &\leq\overline J(E,\eta):= \sup_{a\geq-1/8+\Omega/2}\frac{a+1}{|a-\zeta|}. \tag{10.11}\end{align}

The inequality can be strict. The half-line in the last expression contains spectral gaps and cannot generally replace σ(A0)\sigma(A_0) in an equality.

Example 10.2 (A strict gap in the half-line bound)

Take Ω=.01\Omega=.01, E=−.117E=-.117, η=.0001\eta=.0001. The lowest spectral points of A0A_0 are −.120-.120 and −.110-.110; the n≥3n\geq3 electronic ladders begin above −.051-.051, and the continuum begins at .005.005. At a=Ea=E, the half-line expression is 88308830. On the actual spectrum the maximum is

Jspec=.88.0032+.00012<294. J_{\rm spec}=\frac{.88}{\sqrt{.003^2+.0001^2}}<294.

Indeed the first point gives a value above 280280, while for every other spectral point a≥−.110a\geq-.110 the quotient is at most .89/.007<128.89/.007<128. Thus the half-line equality fails by a large factor even for this concrete parent.

Theorem 10.3 (An earned low-window inverse for the actual block)

If J‾θ<1\overline J\theta<1, then

∥K01/2(A−ζ)−1LHs−1/2∥≤∣g∣1−J‾θ{2Ωsup⁡s≥Ω/2∫e+s+1∣e+s−ζ∣2 μfR(de)}1/2. \|K_0^{1/2}(A-\zeta)^{-1}LH_s^{-1/2}\| \leq\frac{|g|}{1-\overline J\theta} \left\{\frac2\Omega\sup_{s\geq\Omega/2} \int\frac{e+s+1}{|e+s-\zeta|^2}\,\mu_{f_R}(de)\right\}^{1/2}. (10.12)

For the static row

Ω=1/100,∣g∣≤10−6,R=40,d0≤41,E≤−.47,η>0, \Omega=1/100,\quad |g|\leq10^{-6},\quad R=40,\quad d_0\leq41, \qquad E\leq-.47,\quad\eta>0, (10.13)

the complete physical sandwich satisfies

∥Tph1/2(A−E−iη)−1LHs−1/2∥2<4.035635⋅10−9<4.05⋅10−9. \|T_{\rm ph}^{1/2}(A-E-i\eta)^{-1}LH_s^{-1/2}\|^2 <4.035635\cdot10^{-9}<4.05\cdot10^{-9}. (10.14)
Proof

Let V0=K0−1/2gYQdRQK0−1/2V_0=K_0^{-1/2}gYQd_RQK_0^{-1/2} and B0=K01/2(A0−ζ)−1K01/2B_0=K_0^{1/2}(A_0-\zeta)^{-1}K_0^{1/2}. The bounded form pencil of A−ζA-\zeta has inverse

K01/2(A−ζ)−1K01/2=(I+B0V0)−1B0. K_0^{1/2}(A-\zeta)^{-1}K_0^{1/2} =(I+B_0V_0)^{-1}B_0.

The order is fixed: the pencil is B0−1+V0=B0−1(I+B0V0)B_0^{-1}+V_0=B_0^{-1}(I+B_0V_0). The Neumann bound is ∥(I+B0V0)−1∥≤(1−J‾θ)−1\|(I+B_0V_0)^{-1}\|\leq(1-\overline J\theta)^{-1}. This is the concrete form-inverse construction of Theorem 5.1; no Hilbert-norm boundedness of YQdRQYQd_RQ has been assumed.

In the baseline squared norm, integrate out only the electron spectral measure. The remaining positive source operator is

Hs−1/2YF(Hs)YHs−1/2,F(s)=∫e+s+1∣e+s−ζ∣2 μfR(de). H_s^{-1/2}YF(H_s)YH_s^{-1/2},\qquad F(s)=\int\frac{e+s+1}{|e+s-\zeta|^2}\,\mu_{f_R}(de).

Bound FF by its supremum, then use ∥YHs−1/2∥≤2/Ω\|YH_s^{-1/2}\|\leq\sqrt{2/\Omega}. This proves (10.12). Moving YY through F(Hs)F(H_s) or through the resolvent would not prove that estimate.

For (10.13), θ<.00062\theta<.00062 and J‾≤88/35\overline J\leq88/35. To see the latter, first lower every denominator to a+.47a+.47 and use a≥−.12a\geq-.12; the resulting (a+1)/(a+.47)(a+1)/(a+.47) decreases and has value 88/3588/35 at the floor. Thus the correction in (10.11) leaves the low-window bound unchanged.

The source supremum also needs its own argument. First dominate the integral kernel at the fixed endpoint E=−.47,η=0E=-.47,\eta=0, since e+s≥−.12e+s\geq-.12. At this endpoint the derivative of (e+s+1)/(e+s+.47)2(e+s+1)/(e+s+.47)^2 with respect to ss has sign −(e+s+1.53)<0-(e+s+1.53)<0. It is consequently enough to use s=1/200s=1/200. This monotonicity was not asserted for every negative EE before making the endpoint domination.

For the uncut forcing, isolate the exact 2p2p mass w2=32768/59049w_2=32768/59049. All remaining spectral mass lies at e≥−1/18e\geq-1/18, and the same endpoint kernel is decreasing in ee. Its complete bound-plus-continuum integral is therefore

Ff(1/200)≤w235249+(1−w2)12304822801<6.4. F_f(1/200)\leq w_2\frac{352}{49}+(1-w_2)\frac{123048}{22801}<6.4 . (10.15)

This analytic ceiling requires neither a continuum quadrature nor a truncation of the Rydberg series.

The compact forcing changes the baseline weighted inverse norm, before multiplication by ∣g∣|g|, by at most

J‾ ϵR2Ω(7/8). \overline J\,\epsilon_R\sqrt{\frac2{\Omega(7/8)}}.

This follows by inserting K0−1/2K_0^{-1/2} and applying its lower form floor to fR−ff_R-f and the ordered source factor. Use (10.8), ϵR<6⋅10−15\epsilon_R<6\cdot10^{-15}, 1280<35.778\sqrt{1280}<35.778 and 1600/7<16\sqrt{1600/7}<16. The resulting entirely rational upper bound is

227 10−12[35.778+(88/35)(6⋅10−15)16]2[1−(88/35)(.00062)]2<4.035635⋅10−9. \frac{22}{7}\,10^{-12} \frac{\big[35.778+(88/35)(6\cdot10^{-15})16\big]^2} {[1-(88/35)(.00062)]^2} <4.035635\cdot10^{-9}.

This proves (10.14), retaining the actual excited-block feedback in the inverse.

□

The result is a uniform frequency-window statement with source weight Hs1/2H_s^{1/2}. It does not say that the actual time-dependent input pp has Fourier support in this window. Such a use requires the temporal band and complementary-frequency terms of the window theorem. We next give a different all-frequency bound with the stronger, explicitly earned source weight HsH_s.