computo ergo sum

2026-10-09 · chapter Yang–Mills and the mass gapPart 11 Further considerations — beyond Assumption H, and other viewslocal Poincaré constant, ratio form, sector H · Kiichi, Shiori and Rin

The whole book Contents and reading orders
  1. Part 0 Entrance — how to read this book
  2. 0-01 How to read this book
  3. 0-02 One picture
  4. 0-03 Reading the problem statement word by word
  5. 0-04 Four dimensions in mathematics and four dimensions in physics
  6. Part 1 Mathematical preparation
  7. 1-01 Vector spaces and linear maps
  8. 1-02 What a group is
  9. 1-03 Lie groups and Lie algebras
  10. 1-04 SU(2) and SU(3)
  11. 1-05 Manifolds and tangent spaces
  12. 1-06 Differential forms and the exterior derivative
  13. 1-07 Vector bundles and connections
  14. 1-08 Probability and measure
  15. 1-09 Probability in infinite dimensions
  16. 1-10 Hilbert spaces and self-adjoint operators
  17. 1-11 Fourier analysis and distributions
  18. 1-12 Detour: what happens only in four dimensions
  19. Part 2 Physical preparation
  20. 2-01 Lagrangians and the action
  21. 2-02 The idea of a field
  22. 2-03 Electromagnetism is a gauge theory
  23. 2-04 Special relativity and spacetime
  24. 2-05 The bones of quantum mechanics
  25. 2-06 The harmonic oscillator and creation and annihilation
  26. 2-07 The idea of the path integral
  27. 2-08 Statistical mechanics and phase transitions
  28. 2-09 Detour: the gap and the correlation length in the Ising model
  29. 2-10 The relaxation time and the dynamical exponent z
  30. Part 3 Yang–Mills theory (classical)
  31. 3-01 The gauge principle
  32. 3-02 Non-abelian gauge fields
  33. 3-03 The action and the equations
  34. 3-04 Gauge theory as geometry
  35. 3-05 Instantons and topology
  36. 3-06 Detour: Donaldson and exotic R⁴
  37. 3-07 Yang–Mills inside the Standard Model
  38. Part 4 Quantisation
  39. 4-01 Canonical quantisation and the Hamiltonian
  40. 4-02 The path integral and Euclideanisation
  41. 4-03 Perturbation theory and Feynman diagrams
  42. 4-04 Divergences and renormalisation
  43. 4-05 The algebra of divergences
  44. 4-06 Asymptotic freedom
  45. 4-07 Dimensional transmutation and Λ
  46. 4-08 Gauge fixing and Faddeev–Popov
  47. 4-09 The axioms of quantum field theory
  48. 4-10 The Osterwalder–Schrader axioms and reconstruction
  49. 4-11 The definition of the mass gap
  50. 4-12 Detour: the perturbation series diverges
  51. Part 5 Lattice gauge theory
  52. 5-01 Wilson's lattice
  53. 5-02 The strong-coupling expansion
  54. 5-03 Reflection positivity and the transfer matrix
  55. 5-04 The infinite-volume limit and the cluster expansion
  56. 5-05 Weak coupling and the continuum limit
  57. 5-06 How U(1) differs from the non-abelian case
  58. 5-07 The Monte Carlo method
  59. 5-08 Measuring glueballs and the string tension
  60. 5-09 What to hold fixed when taking the limit
  61. 5-10 Lattice gauge theory with finite groups
  62. 5-11 Detour: Bakry–Émery and one-link integration
  63. Part 6 Constructive field theory
  64. 6-01 What constructive field theory is
  65. 6-02 Solvability in two dimensions and the Yang–Mills measure
  66. 6-03 Constructing scalar fields
  67. 6-04 The cluster expansion
  68. 6-05 The sequence of renormalisation group steps
  69. 6-06 Ultraviolet stability of three-dimensional Yang–Mills
  70. 6-07 Four dimensions
  71. 6-08 Triviality of φ⁴ in four dimensions
  72. 6-09 Stochastic quantisation and regularity structures
  73. 6-10 Where four dimensions stops
  74. 6-11 Obstacles other than divergence
  75. 6-12 Detour: "if 1/0 is given a symbol"
  76. Part 7 From the side of physics
  77. 7-01 How physics sees it
  78. 7-02 Mechanisms of confinement
  79. 7-03 The string picture
  80. 7-04 Large N
  81. 7-05 String theory and extra dimensions
  82. 7-06 How extra dimensions become invisible
  83. 7-07 Where gauge fields come from
  84. 7-08 Holography
  85. 7-09 The mass gap becomes geometry
  86. 7-10 Back to four dimensions
  87. 7-11 Supersymmetry and Seiberg–Witten
  88. 7-12 The sentence that plays the role of an equivalence principle
  89. 7-13 Where the way physics digs parts from mathematics
  90. Part 8 A dictionary of two languages — the physical and the mathematical view
  91. 8-01 How to read the dictionary
  92. 8-02 Dictionary A
  93. 8-03 Dictionary B
  94. 8-04 Dictionary C
  95. 8-05 The physical counterparts of our assumptions
  96. Part 9 Where things stand, and open tasks
  97. 9-01 How far the world has come
  98. 9-02 Where the two ways of digging part
  99. 9-03 Candidates for new concepts
  100. 9-04 The list of open tasks
  101. 9-05 Common misconceptions
  102. Part 10 Towards a proof of the mass gap — building the first step of the staircase
  103. 10-00 Entrance — the staircase, and the random walk, the ruler and the clock
  104. 10-01 The line of construction and Assumption H
  105. 10-02 Roads tried on the four-dimensional lattice, and walls
  106. 10-03 The four steps of the staircase — why we start from 0+1 dimensions
  107. 10-04 The path measure of the double well, and kinks
  108. 10-05 The statement of the first step — four conditions and Proposition 4.5
  109. 10-06 (H1) Local Poincaré within a phase
  110. 10-07 The map of (H2) — seven routes and the seam of the ring
  111. 10-08 What computer-assisted means — the conditions on the chain inside the window
  112. 10-09 The sector framework and the three strands of route 5
  113. 10-10 The list of detour plans — types of breakage
  114. 10-11 (H3)(H4) and the constant of the core
  115. 10-12 The integrated table and the dependency graph
  116. 10-13 Lean statements and the limits of machine checking
  117. 10-14 Reconciliation — the numbers of the record and the known numbers
  118. 10-15 What remains and its cost — the distance to a theorem
  119. 10-16 What is not claimed
  120. 10-17 Insights and small questions
  121. Part 11 Further considerations — beyond Assumption H, and other views
  122. 11-00 Further considerations — entrance
  123. 11-01 One form that obstructs H — a nearly conserved global quantity
  124. 11-02 Choosing the ruler and the coordinates again — the length at which conservation breaks
  125. 11-03 Two ways to repair H — the sector H and the local H
  126. 11-04 Which H the one-sided bridge needs
  127. 11-05 Making time continuous — the Hamiltonian lattice and the vacuum measure
  128. 11-06 Paying with rarity instead of convexity — renormalisation on groups and log-Sobolev
  129. 11-07 Because it is four dimensions — the dimensionless coupling and topology
  130. 11-08 Questions, and what is not claimed
  131. 11-A1 Table of notation for Part 11
  132. Appendices
  133. A-01 Table of notation
  134. A-02 Glossary
  135. A-03 Guide to the literature
  136. A-04 Lean and machine checking
  137. A-05 How this book was made
  138. A-06 Index of assumptions

Two ways to repair H — the sector H and the local H — two forms that restate H to avoid the pattern

What this chapter shows — We define two forms that restate Assumption H so as to avoid the pattern of 11-01 (a nearly conserved global quantity). The local H is a sentence about the Poincaré constant CPloc(c)C_P^{\rm loc}(c) over functionals supported in a window of length cℓc\ell; it is fixed by the marginal law on the window alone, and returns unconditionally to the global CPC_P as c→∞c\to\infty. But the form "CPloc≤K(c)ℓ2C_P^{\rm loc}\le K(c)\ell^2 for some K(c)K(c)" holds even for the massless free field and is empty, so it must be stated by the ratio KrelK_{\rm rel} to the massless value on the same box. The sector H is a sentence about the Poincaré constant in each sector of the smoothed topological charge; it pushes the obstruction to H into a single quantity between sectors, CtransC_{\rm trans}, but it does not become a bridge to the mass gap. Seen through the charge of a subregion, the local H asks about the transport coefficient dd, and the global H about the coefficient of breaking of conservation hh.

Prerequisite chapters — 11-01 (the pattern, and the two accounts of (4)–(7)), 10-01 §05 ((13)–(15) for Assumption H and H↑, the note on topological sectors), 10-01 §06 (the setting of Proposition B), 10-11 §02 (Proposition H3 and the closed box CboxC_{\rm box}). Notation in 11-A1.

Said first — The level is [Res]; only §01 is written to be readable at [Y3]. The core of this chapter is definitions, and neither of the two forms of H has been shown at any β\beta. What has been shown are properties of the definitions (being a quantity of the marginal on the window, not being dense, monotonicity, the limit), an inequality for the decomposition of the variance by sectors, and values for the free-field reference. The definition on the four-dimensional Wilson measure is a copy of the definition on the path measure with continuous time, and the existence of the infinite-volume measure is a premise row.

The order of this chapter
  1. Summary — a section readable at [Y3]
  2. Definition of the local H — the algebra of time-averaged functionals D\mathcal D, the window families Dc\mathcal D_c, Proposition 1 ((1)–(4))
  3. The ratio form and the gauge-quotient reference — the emptiness of the absolute form, KrelK_{\rm rel}, gauge-invariant references, the note on 0+1 ((5)–(7), Table 1)
  4. The sector H — cuts at regular values, the reflecting form, Proposition 2 and the sandwich, three weaknesses ((8)–(11))
  5. Open boxes and closed boxes, two coefficients — local asks dd, global asks hh, Table 2 (the order of volume and a→0a\to0)
  6. Table of the five grades — Table 3 / dependency graph
  7. What cannot be said

01

Summary

A section readable at [Y3]. Assumption H is a sentence about "every test function", so if the relaxation of a quantity of the pattern of 11-01 (a winding number, the topological charge) grows faster than ξ2\xi^2, that alone breaks the upper half H↑ ((3) of 11-01). Such a quantity is global, local neither in time nor in space. So we restrict the test functions in two ways and restate H.

The local H. Restrict the test functions to those depending only on configurations inside a window of length cℓc\ell (in four dimensions, a spacetime box of side cℓc\ell). ℓ\ell is a ruler given from outside, independently of the gap; in four dimensions it is the bookkeeping length ξRG\xi_{\rm RG}. The supremum CPloc(c)C_P^{\rm loc}(c) is fixed by the marginal distribution on the window alone, increases monotonically as the window widens, and returns exactly to the global CPC_P as c→∞c\to\infty. But in a four-dimensional box, CPlocC_P^{\rm loc} is finite, of order the square of the side of the box, even for the massless free field. Merely satisfying "CPloc≤Kℓ2C_P^{\rm loc}\le K\ell^2" says nothing, so we ask that the ratio KrelK_{\rm rel} to the massless value on the same box be sufficiently smaller than 1.

The sector H. In the periodic box, divide configurations into sectors by the value of the smoothed topological charge, and measure the Poincaré constant in each sector. Splitting the variance into within sectors and between sectors, the global CPC_P is sandwiched: above by the sum of "the worst constant within a sector" and "the quantity between sectors CtransC_{\rm trans}", and below by CtransC_{\rm trans}. Assuming the sector H, H↑ becomes the same as Ctrans≲ξ2C_{\rm trans}\lesssim\xi^2. The obstruction does not vanish; it only moves into one quantity.

What is asked. Writing the ratio for the charge of a subregion with two coefficients ((7) of 11-01), the local H↑ needs the transport coefficient of the charge dd not to be too small, and the global H↑ needs the coefficient of breaking of conservation of the charge hh not to be too small. In four dimensions, the freezing of the topological charge acts on the hh side, so the local H is expected not to be affected by freezing Estimate. But the local H does not become a part of the chain that builds H↑; it is a separate sentence (the dependency graph of §06). That what the one-sided bridge needs is the side local in time (under the assumptions of Proposition B) is treated in the chapter on the bridge, 11-04.

02

Definition of the local H

Setting. We use the same setting as Proposition B of Part 10 ((17) of 10-01): a finite spatial lattice, the configuration space of one time Q\mathcal Q (a finite-dimensional connected Riemannian manifold with metric MM), H=−ℏ22ΔM+VH=-\frac{\hbar^2}2\Delta_M+V with assumption (A1) (discrete spectrum, simple ground state ψ0>0\psi_0\gt0, Δ=E1−E0>0\Delta=E_1-E_0\gt0), μ\mu the stationary path measure with T=∞T=\infty (one-time distribution ψ02\psi_0^2, transition e−τAe^{-\tau A}, A=(H−E0)/ℏA=(H-E_0)/\hbar), and m=Δ/ℏm=\Delta/\hbar. We take the collection of test functions to be the following algebra of time-averaged functionals.

D:={f=Φ(∫h1(τ)F1(q(τ)) dτ,…,∫hk(τ)Fk(q(τ)) dτ)},EG(f)=ℏ∫E⟨dq(τ)f, G dq(τ)f⟩ dτ(1)\mathcal D:=\Bigl\{f=\Phi\Bigl(\int h_1(\tau)F_1(q(\tau))\,d\tau,\dots,\int h_k(\tau)F_k(q(\tau))\,d\tau\Bigr)\Bigr\},\qquad \mathcal E_G(f)=\hbar\int\mathbb E\bigl\langle d_{q(\tau)}f,\,G\,d_{q(\tau)}f\bigr\rangle\,d\tau \tag{1}

Here Φ∈Cb∞(Rk)\Phi\in C_b^\infty(\mathbb R^k), Fi∈C∞(Q)F_i\in C^\infty(\mathcal Q) (up to polynomial growth for Q=Rn\mathcal Q=\mathbb R^n), and the weights hi∈L∞(R)h_i\in L^\infty(\mathbb R) have bounded support. dq(τ)f=∑i∂iΦ⋅hi(τ) dFi(q(τ))d_{q(\tau)}f=\sum_i\partial_i\Phi\cdot h_i(\tau)\,dF_i(q(\tau)), and the metric GG satisfies (A3) of Proposition B. The global Poincaré constant is defined as CP:=sup⁡f∈D, E(f)>0Var⁡(f)/E(f)C_P:=\sup_{f\in\mathcal D,\ \mathcal E(f)\gt0}\operatorname{Var}(f)/\mathcal E(f) over D\mathcal D. The test functions of Proposition B, fT=∫0TF(q) dτf_T=\int_0^TF(q)\,d\tau, belong to this D\mathcal D.

Definition 1 (local Poincaré constant)

For a ruler of length ℓ>0\ell\gt0 and c>0c\gt0, put the window Wc:=[0,cℓ]W_c:=[0,c\ell] and

Dc:={f∈D: every weight hi has support in Wc },CPloc(c):=sup⁡f∈Dc, E(f)>0Var⁡(f)E(f)(2)\mathcal D_c:=\{f\in\mathcal D:\ \text{every weight }h_i\text{ has support in }W_c\text{ }\},\qquad C_P^{\rm loc}(c):=\sup_{f\in\mathcal D_c,\ \mathcal E(f)\gt0}\frac{\operatorname{Var}(f)}{\mathcal E(f)} \tag{2}

ℓ\ell is not the length fixed by the gap, ξ=ℏ/Δ\xi=\hbar/\Delta, but a length given from outside (in four dimensions, the bookkeeping length ξRG\xi_{\rm RG}).

ℓ\ell is not fixed by the gap because, when a lower bound on the gap is derived from the local H in 11-04, the argument would be circular if the gap entered the length of the window. Since the measure is stationary, the position of the window does not affect the value (the interval [a,a+cℓ][a,a+c\ell] gives the same value).

Proposition 1 (properties of the local Poincaré constant)

(i) CPloc(c)C_P^{\rm loc}(c) is fixed only by the marginal law of the path on the window, μ∣Wc\mu|_{W_c}, and the Dirichlet form inside the window.

(ii) Dc\mathcal D_c is not dense in L2(μ)L^2(\mu).

(iii) If c≤c′c\le c', then CPloc(c)≤CPloc(c′)≤CPC_P^{\rm loc}(c)\le C_P^{\rm loc}(c')\le C_P.

(iv) lim⁡c→∞CPloc(c)=CP\displaystyle\lim_{c\to\infty}C_P^{\rm loc}(c)=C_P. This limit needs no assumption.

Proved here Proof. (i) f∈Dcf\in\mathcal D_c is fixed only by the values of the path inside the window (the path is continuous, and ∫hF(q) dτ\int h F(q)\,d\tau is the limit of Riemann sums over points inside the window). For τ∉Wc\tau\notin W_c, dq(τ)f=0d_{q(\tau)}f=0, so E(f)=ℏ∫WcE⟨⋯ ⟩ dτ\mathcal E(f)=\hbar\int_{W_c}\mathbb E\langle\cdots\rangle\,d\tau, and both the variance and the Dirichlet form are expectations under the marginal law on the window.

(ii) The closure of Dc\mathcal D_c lies in L2(FWc)L^2(\mathcal F_{W_c}), the space of functions measurable with respect to the σ\sigma-algebra FWc\mathcal F_{W_c} generated by the path inside the window. The value F(q(τ0))F(q(\tau_0)) at a time τ0\tau_0 outside the window (FF non-constant) is not measurable with respect to FWc\mathcal F_{W_c}: with s>0s\gt0 the distance from the end of the window, the conditional expectation is of the form ψ0−1e−sA(Fψ0)\psi_0^{-1}e^{-sA}(F\psi_0), which under (A1) does not coincide with FF itself.

(iii) If c≤c′c\le c', then Dc⊆Dc′⊆D\mathcal D_c\subseteq\mathcal D_{c'}\subseteq\mathcal D, and the supremum over a subset is smaller.

(iv) The weights in D\mathcal D have bounded support, so taking the window as [−cℓ/2,cℓ/2][-c\ell/2,c\ell/2] by stationarity, D=⋃cDc\mathcal D=\bigcup_c\mathcal D_c. If b<CPb\lt C_P, there is f∈Df\in\mathcal D whose ratio exceeds bb, and that ff lies in Dc\mathcal D_c for some cc, so CPloc(c)>bC_P^{\rm loc}(c)\gt b. Together with the monotonicity of (iii), the limit is CPC_P. ∎

Lean LatticeGauge.LocalH.local_le_global (assumptions: bounded above, non-empty, subset) and local_approaches_global (assumptions: S=⋃cScS=\bigcup_cS_c, bounded above, non-empty; conclusion: every bb smaller than sup⁡S\sup S is exceeded by sup⁡Sc\sup S_c for some cc) check only the part of (iii)(iv) about suprema of sets of real numbers. The path measure, D\mathcal D and E\mathcal E are outside Lean.

(iv) holds without assumptions because CPC_P was defined over D\mathcal D. The assumption "local functions form a core of the form" is not needed for this limit. The question of the core remains only when one identifies CP(D)C_P(\mathcal D) with the gap of the generator of the equation of stochastic quantisation (the SPDE of Langevin dynamics) (the gap of the generator of the closure of the form on D\mathcal D is 1/CP(D)1/C_P(\mathcal D), and whether it coincides with the generator of the SPDE is the question of the core).

The local H. On Definition 1, we write the local H at two levels.

Hcloc: lim⁡ln⁡CPloc(c)ln⁡ℓ=2,H↑cloc(K): CPloc(c)≤K ℓ2(3)\mathrm H^{\rm loc}_c:\ \lim\frac{\ln C_P^{\rm loc}(c)}{\ln\ell}=2,\qquad \mathrm{H}{\uparrow}^{\rm loc}_c(K):\ C_P^{\rm loc}(c)\le K\,\ell^2 \tag{3}

(left: the power statement for families with ℓ→∞\ell\to\infty; right: the absolute form of its upper half). Two things follow in one line from Proposition 1 Proved here. First, the global H↑ CP≤Kℓ2C_P\le K\ell^2 implies H↑cloc(K)\mathrm{H}{\uparrow}^{\rm loc}_c(K) with the same constant for every cc ((iii)). Second, if H↑cloc(K)\mathrm{H}{\uparrow}^{\rm loc}_c(K) holds for every cc with a KK uniform in cc, it returns by (iv) to the global H↑. So the local H↑ has content different from the global H↑ only when stated with a single cc fixed.

A version local in space too. On an infinite spatial lattice (or a spatial lattice containing the box), take the product B×WcB\times W_c of a spatial box BB and a window, and define in the same form the family DB,c\mathcal D_{B,c}, with FiF_i restricted to single-time functions depending only on variables in BB, and CPloc(B,c)C_P^{\rm loc}(B,c). (i)–(iv) of Proposition 1 hold with the same proof, and the marginal in (i) is the law of the field on B×WcB\times W_c. The local H on the four-dimensional Wilson measure copies this definition onto a spacetime box BcB_c of side cℓc\ell (ℓ=ξRG\ell=\xi_{\rm RG}), treating time and space alike, and the σ\sigma-algebra generated by the links in the box; the Dirichlet form is that of link Langevin, E(f)=E∑ℓ∣∇ℓf∣2\mathcal E(f)=\mathbb E\sum_\ell|\nabla_\ell f|^2. What is presupposed at the copying stage is the existence and uniqueness of the infinite-volume Wilson measure ((S1) of Part 10) Assumption.

03

The ratio form and the gauge-quotient reference

The absolute form is empty. The right-hand form of (3), H↑cloc(K)\mathrm{H}{\uparrow}^{\rm loc}_c(K), holds on a four-dimensional spacetime box, local in space too, even for the massless free field. Writing CPloc,0(R)C_P^{\rm loc,0}(R) for the local Poincaré constant of the infinite-volume massless free scalar field (one component, canonical graduation) on a spacetime box BRB_R of side RR,

R24π2 ≤ CPloc,0(R) ≤ R2(4)\frac{R^2}{4\pi^2}\ \le\ C_P^{\rm loc,0}(R)\ \le\ R^2 \tag{4}

Proved here. The gradient Poincaré constant of a Gaussian measure equals the operator norm of the covariance compressed to the subspace spanned by the family (a transcription to subspaces of Lemma 2.2 of Hairer–Stuart–Voss–Wiberg 2005) Cited, so CPloc,0(R)=∥PB(−Δ)−1PB∥C_P^{\rm loc,0}(R)=\|P_B(-\Delta)^{-1}P_B\|. In four dimensions (−Δ)−1(-\Delta)^{-1} is finite (transient) and its kernel is continuous, of the type 1/(4π2∣z∣2)1/(4\pi^2|z|^2), so the Schur estimate sup⁡x∑y∈BG(x−y)≤∫∣z∣<2Rd4z/(4π2∣z∣2)=R2\sup_x\sum_{y\in B}G(x-y)\le\int_{|z|\lt2R}d^4z/(4\pi^2|z|^2)=R^2 gives the upper side, and the value with the Dirichlet ground state of the box as test function gives the lower side. Hence, reading ℓ=R/c\ell=R/c, H↑cloc(K)\mathrm{H}{\uparrow}^{\rm loc}_c(K) holds with K=c2K=c^2, and the form "CPloc(c)≤K(c)ℓ2C_P^{\rm loc}(c)\le K(c)\ell^2 for some K(c)K(c)" says nothing about the gap. This is the negative control of this definition (the massless free field). In numbers, Γ(R):=CPloc,0(R)/R2\Gamma(R):=C_P^{\rm loc,0}(R)/R^2 is 0.0802, 0.0768, 0.0756, 0.0750, 0.0747, 0.07440.0802,\ 0.0768,\ 0.0756,\ 0.0750,\ 0.0747,\ 0.0744 at R=4,6,8,10,12,16R=4,6,8,10,12,16; the correction is 1/R21/R^2 with no logarithmic correction, and Γ∞=0.0740\Gamma_\infty=0.0740 Reading (floating point, numerical integration of the heat kernel on the infinite lattice, extrapolation from R≤16R\le16; within relative 2⋅10−32\cdot10^{-3} of an independent route via periodic lattices). The massless field itself satisfies K(c)=0.0740 c2K(c)=0.0740\,c^2.

One line of contrast with lower dimensions. For massless fields in two spacetime dimensions the infrared diverges and CPloc=∞C_P^{\rm loc}=\infty; localising only to a time window on a finite spatial lattice, the constant mode gives CPloc≈T/(2m)C_P^{\rm loc}\approx T/(2m) (mT≪1mT\ll1), which diverges as m→0m\to0. A massless field has a finite local constant in spacetime dimension three or more when localised in space too, and the four-dimensional setting of Part 11 is exactly that case Proved here.

Definition 2 (the ratio form)

Put the ratio of the local Poincaré constant of the target measure μ\mu (the Wilson measure, or the path measure in continuous time) on the box BcℓB_{c\ell} to the value of the massless reference with a Dirichlet form on the same lattice, the same box and the same graduation as

Krel(c):=CPloc(Bcℓ;μ)CPloc,0(cℓ),H↑crel(K): Krel(c)≤K(β≥β0 uniformly, ℓ=ξRG)(5)K_{\rm rel}(c):=\frac{C_P^{\rm loc}(B_{c\ell};\mu)}{C_P^{\rm loc,0}(c\ell)},\qquad \mathrm{H}{\uparrow}^{\rm rel}_c(K):\ K_{\rm rel}(c)\le K\quad(\beta\ge\beta_0\text{ uniformly},\ \ell=\xi_{\rm RG}) \tag{5}

The local H↑ is this sentence at a single cc; it is not required uniformly in cc.

It corresponds to the constant of the absolute form by K(c)=Krel Γ c2K(c)=K_{\rm rel}\,\Gamma\,c^2 Proved here. In the ratio form the constant KK becomes an absolute number independent of the box size, and "sufficiently smaller than 1" has meaning.

Why it is not required uniformly in cc. For the free field of mass mm the ratio is a function of mRmR alone, r(mR)r(mR), and is 0.932, 0.825, 0.623, 0.359, 0.07720.932,\ 0.825,\ 0.623,\ 0.359,\ 0.0772 at mR=0.5, 1, 2, 4, 12mR=0.5,\ 1,\ 2,\ 4,\ 12 Reading (agreeing within 0.3%0.3\% for boxes of side 44 to 1212). When the box is smaller than the correlation length (mR→0mR\to0) the ratio tends to 1. An asymptotically free theory is close to a free field at short distance, so a sentence requiring K<1K\lt1 uniformly down to c→0c\to0 is expected to be false Estimate. For a field whose action is a convex perturbation 12ϕ(−Δ)ϕ+∑U(ϕx)\tfrac12\phi(-\Delta)\phi+\sum U(\phi_x) (UU convex), the Brascamp–Lieb inequality gives Krel≤1K_{\rm rel}\le1 Assumption (the statement of the inequality in the original source has not been checked in this part). What the bridge needs is not that the ratio is below 1 but that it is below the threshold K∗K_*, and the threshold moves with the choice of reference: 0.342κ0.342\kappa (scalar), 0.502κ0.502\kappa (gauge quotient, one-colour linearisation), ≈0.62κ\approx0.62\kappa (colour singlet of SU(2)SU(2), leading term). The threshold, and that the band [K∗,1)[K_*,1) is undecided, are treated in 11-04.

The reference for gauge fields is taken on the gauge quotient. For four-dimensional gauge fields, the value of the reference changes with the test space in which it is measured. The target Wilson measure is gauge invariant, and the Poincaré constant of a non-gauge-invariant function is infinite along gauge orbits, so the numerator of the ratio is finite only on gauge-invariant functions. So the reference in the denominator is also measured on gauge-invariant functions of the same box.

VF:={gradients of functions of the plaquette angles of the box}=d∗(ℓ2(PR)),VQ:={gradients of functions invariant under gauge transformations at all sites of the box}(6)V_F:=\{\text{gradients of functions of the plaquette angles of the box}\}=d^*\bigl(\ell^2(P_R)\bigr),\qquad V_Q:=\{\text{gradients of functions invariant under gauge transformations at all sites of the box}\} \tag{6}

If the box is contractible, VF=VQV_F=V_Q Proved here (the cubical complex is contractible with zero first homology, so cycles in the graph of the box are boundaries of 2-chains of plaquettes). In non-contractible regions (with holes), VF⊊VQV_F\subsetneq V_Q. Gauge-fixed references (Feynman gauge and so on) depend on the fixing parameter α\alpha, with ΓQ≤ΓLandau≤Γα=1\Gamma_Q\le\Gamma_{\rm Landau}\le\Gamma_{\alpha=1}, and moreover Γα≥α/(λDintR2)\Gamma_\alpha\ge\alpha/(\lambda_D^{\rm int}R^2), so they become infinite as α→∞\alpha\to\infty (removing the fixing) Proved here. The numbers are in Table 1.

Table 1 References for the four-dimensional box (one-colour Gaussian approximation, β=1\beta=1, canonical graduation, floating point, extrapolation from R≤16R\le16; λW\lambda_W is the Dirichlet value of the box within the test space times R2R^2)
ReferenceTest spaceΓ∞\Gamma_\inftyλW,∞\lambda_{W,\infty}As a reference
Scalar (one component)All functions on the box0.07400.0740 Reading4π2=39.54\pi^2=39.5Not used for gauge fields
Feynman gauge (α=1\alpha=1)All functions of the links of the box0.07400.0740 Reading39.539.5Depends on α\alpha; not intrinsic
Gauge quotientVQ=VFV_Q=V_F (functions of plaquette angles)0.02770.0277 Reading72.072.0 ReadingIndependent of α\alpha. This one is used
Variant with the boundary gauge frozenDivided only by gauge transformations at inner sites2.222.22 to 2.532.53 times the gauge quotient (side 44 to 1212) Reading—Not gauge invariant (flux through the box enters)

The last row of Table 1 is (e) of Table 1 in 11-01. Gauge transformations at the boundary sites of the box also act on links inside the box, so gauge-invariant observables of the box (Wilson loops and so on) lie in the space divided at all sites. "Dividing by gauge transformations at all sites of the box" is part of the definition, and leaving it out moves the numbers by a factor of 2.22.2 to 2.52.5. Every reference is a number for a free field; this book has not measured a single ratio for the target Wilson measure.

Note on 0+1. In 0+1 dimensions there is no finite massless reference (for a free particle CPloc=∞C_P^{\rm loc}=\infty). The reference always has a scale, and for the double well we take the harmonic oscillator with the curvature of the bottom (angular frequency ωb\omega_b). Its ratio for the shortest window (a single time) is exactly ωb/m\omega_b/m (when ψ0\psi_0 is the Schrödinger ground state) Proved here:

Krel(single time)=ε/(2m)ε/(2ωb)=ωbm(7)K_{\rm rel}(\text{single time})=\frac{\varepsilon/(2m)}{\varepsilon/(2\omega_b)}=\frac{\omega_b}{m} \tag{7}

(ε\varepsilon is the time step. The numerator is the Poincaré constant of the marginal ψ02\psi_0^2, which moves to the gap of (H−E0)(H-E_0) by the ground-state transformation. This identity is the same as the formula for the vacuum measure in 11-05.) Lean LatticeGauge.LocalHDoubleWell.one_slice_ratio (assumptions: 0<ε,m,ω0\lt\varepsilon,m,\omega; only the algebra of the ratio). In the double well, tunnelling gives m≪ωbm\ll\omega_b, so the ratio does not become 1 even for short windows; on the lattice ε=12\varepsilon=\tfrac12 it is 4.614.61 (ℏ=0.3\hbar=0.3) to 638638 (ℏ=0.08\hbar=0.08) Reading. Hence "the ratio tends to 1 at short distance" is not a fact that follows from the ratio form but an assumption depending on a property of the theory, asymptotic freedom (being close to a free field at short distance) Assumption. The three regimes of the ratio as the window is lengthened are treated in 11-04.

04

The sector H

Setting. Take the periodic box ΛL=(Z/L)4\Lambda_L=(\mathbb Z/L)^4, the configuration space M=Glinks\mathcal M=G^{\text{links}} (a compact connected manifold with a bi-invariant metric), the Wilson measure μ\mu (smooth positive density), and E(f)=∫∣∇f∣2dμ\mathcal E(f)=\int|\nabla f|^2d\mu. For the topological charge we use the lattice charge QsQ_s smoothed by the Wilson flow (flow time ss) or by finitely many smoothings. The smoothing map is smooth and the charge density is a polynomial in matrix elements, so Qs∈C∞(M)Q_s\in C^\infty(\mathcal M).

Definition 3 (sectors, and the form reflecting at the walls)

Take the cuts θn∈(n−1,n)\theta_n\in(n-1,n) at regular values of QsQ_s (by Sard's theorem almost all values are regular, so they can be taken arbitrarily close to n−12n-\tfrac12).

In:={θn≤Qs<θn+1},μn:=μ( ⋅ ∣In),En(f):=∫In∣∇f∣2dμn  (f∈H1(In)),CPsec(n):=sup⁡Var⁡μn(f)En(f)(8)I_n:=\{\theta_n\le Q_s\lt\theta_{n+1}\},\quad \mu_n:=\mu(\,\cdot\,|I_n),\quad \mathcal E_n(f):=\int_{I_n}|\nabla f|^2d\mu_n\ \ (f\in H^1(I_n)),\quad C_P^{\rm sec}(n):=\sup\frac{\operatorname{Var}_{\mu_n}(f)}{\mathcal E_n(f)} \tag{8}

(only for nn with μ(In)>0\mu(I_n)\gt0). No boundary condition is imposed on En\mathcal E_n. Its generator is Langevin reflecting at the walls (Neumann).

Because the cut is at regular values, the closure of a sector is a compact manifold with smooth boundary, and the walls are smooth hypersurfaces of codimension 1. Cutting by a geometrically defined integer-valued charge (piecewise constant and discontinuous), the form can be defined as H1H^1 on open sets, but the regularity of the walls is unknown and (i) below cannot be said. This is why this chapter uses a smoothed charge.

Proposition 2 (sector Poincaré constants and the decomposition of the variance)

(i) CPsec(n)<∞  ⟺  InC_P^{\rm sec}(n)\lt\infty\iff I_n is connected.

(ii) With NN the sector index, for smooth ff,

E(f)=∑nμ(In) En(f),Var⁡f=∑nμ(In)Var⁡μnf+Var⁡(E[f ∣ N])(9)\mathcal E(f)=\sum_n\mu(I_n)\,\mathcal E_n(f),\qquad \operatorname{Var}f=\sum_n\mu(I_n)\operatorname{Var}_{\mu_n}f+\operatorname{Var}\bigl(\mathbb E[f\,|\,N]\bigr) \tag{9}

(iii) For the quantity between sectors Ctrans:=sup⁡fVar⁡(E[f∣N])/E(f)C_{\rm trans}:=\sup_f\operatorname{Var}(\mathbb E[f|N])/\mathcal E(f),

Ctrans ≤ CP ≤ sup⁡nCPsec(n)+Ctrans(10)C_{\rm trans}\ \le\ C_P\ \le\ \sup_nC_P^{\rm sec}(n)+C_{\rm trans} \tag{10}

(iv) CPsec(n)≤CPC_P^{\rm sec}(n)\le C_P does not hold in general.

Proved here Proof. (i) The closure of a sector is compact with smooth boundary and the density is positive and smooth, so the resolvent of the Neumann operator is compact (Rellich's theorem Assumption: the statement in the original source has not been checked in this part). The multiplicity of the zero eigenvalue equals the number of connected components, so a positive gap is the same as connectedness. (ii) The walls have measure 0, so the Dirichlet form splits into a sum over sectors, and the variance is the sum of the expectation of the conditional variance and the variance of the conditional expectation. (iii) The left is Var⁡(E[f∣N])≤Var⁡f\operatorname{Var}(\mathbb E[f|N])\le\operatorname{Var}f; the right uses the Poincaré inequality in each sector on the first term of (9) and closes with ∑nμ(In)En=E\sum_n\mu(I_n)\mathcal E_n=\mathcal E. (iv) Functions on sectors may jump at the walls (they are not in H1(M)H^1(\mathcal M)), so if conditioning creates a new bottleneck, CPsec(n)>CPC_P^{\rm sec}(n)\gt C_P is possible. ∎ Lean LatticeGauge.LocalH.sector_split (assumptions: weights ≥0\ge0, the inequality in each sector, the two formulas of (9), Var⁡(E[f∣N])≤CtransE\operatorname{Var}(\mathbb E[f|N])\le C_{\rm trans}\mathcal E; conclusion: the right of (10)), trans_le_total (assumptions: weights and sector variances ≥0\ge0, (9); conclusion: the inequality for the numerator on the left of (10)). The identity (9) itself, Rellich, and the measure are outside Lean.

The sector H and its corollary. The sector H is the sentence that, in a box with fixed physical side, the Poincaré constant within a sector is bounded by the square of the correlation length.

H↑sec:L=λ ξRG gives sup⁡nCPsec(n)≤K(λ) ξRG2⟹( H↑  ⟺  Ctrans≲ξRG2 )(11)\mathrm{H}{\uparrow}^{\rm sec}:\quad L=\lambda\,\xi_{\rm RG}\ \text{gives}\ \sup_nC_P^{\rm sec}(n)\le K(\lambda)\,\xi_{\rm RG}^2\qquad\Longrightarrow\qquad\bigl(\ \text{H↑}\iff C_{\rm trans}\lesssim\xi_{\rm RG}^2\ \bigr) \tag{11}

Proved here (from (10); ≲\lesssim is up to replacing constants). The sector H pushes the obstruction to H exactly into the quantity between sectors CtransC_{\rm trans}. It does not remove the obstruction but only moves it into one quantity, the same form as type 7 in 10-10 (transfer). The physical reading of CtransC_{\rm trans} is the rate of dislocations, and statically Ctrans≥Var⁡(E[Qs∣N])/E(Qs)C_{\rm trans}\ge\operatorname{Var}(\mathbb E[Q_s|N])/\mathcal E(Q_s).

It does not connect to the bridge. What follows from (10) and the one-sided bridge ((17) of 10-01, with corrections for finite TT in periodic time) goes only as far as κ/m2≲sup⁡nCPsec(n)+Ctrans\kappa/m^2\lesssim\sup_nC_P^{\rm sec}(n)+C_{\rm trans}, and no gap comes out unless CtransC_{\rm trans} is bounded Proved here. The Langevin gap within a sector, 1/CPsec(n)1/C_P^{\rm sec}(n), is a fifth quantity of time, and the conditioned measure μn\mu_n has no transfer operator (the constraint on the total charge breaks the Markov property in time). A "physical gap within a sector" of the type of Proposition B does not stand by definition; to set it up one would need a treatment of superpositions of θ vacua, which has not been formulated Estimate.

Three weaknesses. (a) The walls of conditioning can create artificial bistability. In the core on the box side of Part 10, two local minima appeared on the walls of conditioning the interval to "exactly this interval", giving rise to a bistability that was not physical metastability (10-11 §06). The walls of sectors lie on dislocation configurations of small measure, so we expect the harm to be small, but this has not been checked Estimate. That it is unknown whether sectors are connected in (i) of Proposition 2 is the extreme form of this weakness. (b) When the physical volume is made large, the obstruction remains even with the sector fixed. With β\beta fixed and L→∞L\to\infty, the charge of a half box can move even within a sector InI_n. With the coefficients of (5) in 11-01, the conditional variance is of order χtV/4\chi_tV/4 and the Dirichlet form of order hV/2+g ∣face∣hV/2+g\,|\text{face}|, and the ratio tends to χt/(2h)\chi_t/(2h) as V→∞V\to\infty, the same order as the overall ratio of the periodic box χt/h\chi_t/h Assumption (on the definitions of h,gh,g and the accounting for the conditional variance of a normal distribution with the sum of the two halves fixed). Fixing the sector stops only the one mode of the total charge; the modes of the charges of subregions remain. Hence the sector H is expected to have content different from H↑ only when the box is smaller than the crossing length (subregions within a sector are in the transport regime), that is, to have meaning only in the order in which the physical volume is fixed Estimate. (c) The path measure with T=∞T=\infty has no sectors. The four-dimensional charge is a quantity integrated over time, and for T=∞T=\infty it is not in L2L^2.

Correspondence with the splitting of the first step. (9) is the same splitting as the splitting of the variance in the first step (local Poincaré within a phase, and transport between phases, 10-05 §01), with phase ↔ sector and kink ↔ dislocation Estimate. It is one concrete destination of "the two-scale splitting is expected to lift" in 10-03 §06. But in the first step, the time for transport between phases (diffusion of kinks) is read to be of order ξ2S0/ℏ\xi^2S_0/\hbar ((14) of 10-04 Assumption), and fits into the power form of H. The four-dimensional quantity between sectors CtransC_{\rm trans} is exactly a quantity of the pattern of 11-01, and there is no prospect yet that it fits into the same form.

05

Open boxes and closed boxes, two coefficients

Local asks about the transport coefficient; global asks about the coefficient of breaking of conservation. The charge QwQ_w in a smooth window of (7) in 11-01 belongs to the local family of a box of side R=cξR=c\xi. Putting (7) into the local H↑ (absolute form), the necessary condition is χtc2ξ2/(hc2ξ2+dλW)≤Kξ2\chi_tc^2\xi^2/(hc^2\xi^2+d\lambda_W)\le K\xi^2, and in the regime where hh is small (the crossing length R∗R_* much longer than cξc\xi),

χt(cξ)2d λW≤Kξ2  ⟺  χtc2≤K d λW,that isDeff:=dχt ≥ c2KλW(12)\frac{\chi_t(c\xi)^2}{d\,\lambda_W}\le K\xi^2\iff\chi_tc^2\le K\,d\,\lambda_W,\qquad\text{that is}\qquad D_{\rm eff}:=\frac{d}{\chi_t}\ \ge\ \frac{c^2}{K\lambda_W} \tag{12}

Proved here (algebra) Lean LatticeGauge.LocalH.transport_requirement (assumptions: 0<d0\lt d, 0<λW0\lt\lambda_W, 0<ξ0\lt\xi). In the ratio form, KK is read as KrelΓc2K_{\rm rel}\Gamma c^2. On the other hand, the necessary condition for the global H↑ is (2)(6) of 11-01 with R→∞R\to\infty,

χth ≲ ξ2(13)\frac{\chi_t}{h}\ \lesssim\ \xi^2 \tag{13}

Assumption (on top of (5) of 11-01). (12) and (13) bear on different coefficients. The local H asks about the transport coefficient of the charge dd, and the global H about the coefficient of breaking of conservation of the charge hh. The freezing of the four-dimensional topological charge can be read as the appearance of hh vanishing quickly in the continuum limit (dislocation configurations becoming rare), so what it affects is the side of (13). The prospect that the local H is unaffected by freezing comes from here Estimate. There are no four-dimensional lattice values for dd and hh.

Closed boxes and open boxes. Proposition H3 of Part 10 (10-11 §02) is a reduction bounding the global CPC_P by a box constant CboxC_{\rm box}, and CboxC_{\rm box} was the constant of a conditioned measure with the boundary values fixed (with sup⁡\sup over the boundary values). We call this a closed box. The box of the local H is a marginal box without fixing the boundary, and we call it an open box. In four dimensions, if the boundary links are fixed, the integer part of the topological charge inside the box is expected to change only through dislocations inside the box (in the continuum, the charge of the box is the sum of the Chern–Simons value on the boundary and a winding number) Estimate. Hence for closed boxes of size χt(cξ)4≳1\chi_t(c\xi)^4\gtrsim1, CboxC_{\rm box} is expected to inherit the time of the dislocation barrier Estimate. In open boxes the charge flows in and out through the boundary, and relaxation is of the transport type of (12) Assumption.

The difference between closed and open boxes has the same form as the difference between periodic and open boundaries. Open boundaries remove the topological obstruction only inside a finite box with fixed physical side (the autocorrelation time of Q2Q^2 with open boundaries grows roughly in proportion to the length in the time direction, §5.3 of Lüscher–Schaefer 2011 Reading). This is the transport type of (12) restated in the language of boxes. A reading of the consequence Estimate: if, under the reading that extends the conjecture (§06 (a) of 11-01), H↑ reads as false in four dimensions, then even when the local H↑ holds, the four-dimensional version of Proposition H3 fails at the stage of closed boxes. The place where it breaks is not "relaxation inside the box" but "the passage between sectors inside a closed box".

Table 2 The order of volume and a→0a\to0, and the corrections expected to work
OrderTaken firstCorrections expected to workCorrections expected not to workLabel
a→0a\to0 with the physical side fixedContinuum limit of a finite boxOpen boundaries, the sector H—Cited (original sources on open boundaries), Estimate
Volume to infinity first (the order of this book)Infinite-volume lattice measureThe local H (open boxes)Open boundaries, the sector HAssumption (accounting for the charge of a subregion), Estimate

The original source writes that the scaling of the autocorrelation of algorithms implementing Langevin (1/a21/a^2 in lattice units) "is expected to hold on infinite lattices and on finite lattices with open boundaries", and excludes transitions changing topology with periodic boundaries from the analysis as lattice artefacts (the footnote of Lüscher–Schaefer, Non-renormalizability of the HMC algorithm, 2011) Cited. The second row of Table 2 points the same way as this wording, but the object of the original source is the autocorrelation of local quantities, not the local H itself.

06

Table of the five grades

We put the rows of this chapter into one table in the format of the five grades, with Estimate added. The symbols of the rows are the same as the nodes of the dependency graph, and one row of 11-01 (CL) is carried over.

Table 3 Rows on the sector H and the local H ("—" marks rows without machine checking)
RowStatement (one line)GradeGroundsScopeMachine checking
S1Existence and uniqueness of the infinite-volume Wilson measureAssumption(S1) of Part 10β≥β0\beta\ge\beta_0—
RLRellich's theorem (compactness of the Neumann resolvent)AssumptionProposition 2 (i) (the statement in the original source has not been checked)Smooth boundary—
GPPoincaré constant of a Gaussian measure = norm of the compressed covarianceCited(4), Hairer–Stuart–Voss–Wiberg 2005Gaussian—
L1Proposition 1 (i)–(iv)Proved hereProof in §02Continuous time, finite spatial lattice, T=∞T=\inftylocal_le_global, local_approaches_global (assumptions: bounded above, non-empty, S=⋃ScS=\bigcup S_c; only the supremum part)
W4That the proof of Proposition 1 goes through in the same way for boxes of the four-dimensional Wilson measureAssumptionEnd of §02 (the treatment of domains is not written out)Four dimensions, infinite volume—
LDProperties of the four-dimensional local Poincaré constantProved hereOn S1, L1, W4Four dimensions—
VCThe absolute form holds with K=c2K=c^2 for the massless free fieldProved here(4)Four-dimensional spacetime, local in space too—
GMΓ∞=0.0740\Gamma_\infty=0.0740, ΓQ,∞=0.0277\Gamma_{Q,\infty}=0.0277, λWQ=72.0\lambda_W^Q=72.0, 2.222.22 to 2.532.53 times with the boundary frozenReading§03, Table 1Free field, one-colour Gaussian, β=1\beta=1, R≤16R\le16—
GQVF=VQV_F=V_Q in contractible boxes; gauge-fixed references depend on α\alpha and diverge as α→∞\alpha\to\inftyProved here(6)Contractible box—
OSRatio for the shortest window =ωb/m=\omega_b/mProved here(7)0+1, Schrödinger ψ0\psi_0one_slice_ratio (assumptions: 0<ε,m,ω0\lt\varepsilon,m,\omega)
AFThe ratio tends to 1 at short distanceAssumptionThe note on 0+1 in §03 (depends on asymptotic freedom)Four dimensions—
HRLocal H↑ (ratio form): Krel(c)≤KK_{\rm rel}(c)\le K at a single ccAssumption(5)β≥β0\beta\ge\beta_0—
P2Proposition 2 (i): sector constant finite ⟺ sector connectedProved here§04 (on top of RL)Periodic box, cuts at regular values—
SWThe sandwich (10)Proved here(9)(10)Periodic boxsector_split, trans_le_total (assumptions: weights ≥0\ge0, the inequality in each sector, the two formulas of (9))
COCorollary (11): under the sector H, H↑ ⟺ Ctrans≲ξ2C_{\rm trans}\lesssim\xi^2Proved here(11)Box with fixed physical side—
NBWhat comes out of sectors goes only as far as κ/m2≲sup⁡nCPsec+Ctrans\kappa/m^2\lesssim\sup_nC_P^{\rm sec}+C_{\rm trans}Proved here§04 (on top of Proposition B)Finite box—
CLCluster decay (CL of 11-01)Assumption(5) of 11-01Infinite volume—
TR(12): local asks dd; (13): global asks hhProved here(12) (algebra), (13) on top of CLFour dimensionstransport_requirement (assumptions: 0<d,λW,ξ0\lt d,\lambda_W,\xi)
HBRatio for half boxes within a sector →χt/(2h)\to\chi_t/(2h)AssumptionWeakness (b) of §04L→∞L\to\infty with β\beta fixed—
MX(MIX4) maximal correlation <1\lt1 between families of closed boxes, uniform in β\betaAssumptionPremise of the four-dimensional version of Proposition H3Four dimensions, families of 242^4 colours—
BX(BOX4) Cbox(cξRG)≤K′ξRG2C_{\rm box}(c\xi_{\rm RG})\le K'\xi_{\rm RG}^2 for closed boxesAssumption§05 (the row where the topological barrier is expected to enter)Four dimensions—
RDFour-dimensional multi-family box reduction CP≤C(c) Cbox/(1−calt)C_P\le C(c)\,C_{\rm box}/(1-c_{\rm alt})AssumptionFour-dimensional version of the one-dimensional Proposition H3 (not written out)Four dimensions—
HUH↑Proved hereAlgebra on top of MX, BX, RDFour dimensions—

Dependency graph

[01] ASM S1  infinite-volume Wilson measure exists, unique        β ≥ β₀
[02] ASM RL  Rellich's theorem                                    smooth boundary
[03] CIT GP  Gaussian C_P = norm of compressed covariance         Gaussian
[04] PRV L1  Proposition 1 (path measure, continuous time)        T = ∞
             Lean local_le_global, local_approaches_global (supremum part only)
[05] ASM W4  proof of Proposition 1 goes through in 4D boxes      four dims
[06] PRV LD  properties of the 4D local C_P ⟸ [01][04][05]
[07] PRV VC  emptiness of the absolute form (4) ⟸ [03]            4D spacetime
[08] RDG GM  reference numbers (Γ_∞, Γ_Q, λ_W^Q, freezing factor)  free field
[09] PRV GQ  V_F = V_Q in contractible boxes; fixing depends on α  contractible box
[10] PRV OS  ratio for the shortest window = ω_b/m                0+1
             Lean one_slice_ratio
[11] ASM AF  ratio → 1 at short distance (asymptotic freedom)     four dims
[12] ASM HR  local H↑ (ratio form, one c)                         β ≥ β₀
[13] PRV P2  sector constant finite ⟺ connected ⟸ [02]            regular-value cut
[14] PRV SW  sandwich C_trans ≤ C_P ≤ sup C^sec + C_trans         periodic box
             Lean sector_split, trans_le_total
[15] PRV CO  under the sector H, H↑ ⟺ C_trans ≲ ξ² ⟸ [14]
[16] PRV NB  bridge inequality from sectors ⟸ [14] (+ Prop. B)
[17] ASM CL  cluster decay (11-01)                                infinite volume
[18] PRV TR  local asks d, global asks h ⟸ [17]
             Lean transport_requirement
[19] ASM HB  ratio of half boxes in a sector → χ_t/(2h)
[20] ASM MX  (MIX4) max. correlation of closed-box families < 1   four dims
[21] ASM BX  (BOX4) C_box ≤ K′ξ_RG² for closed boxes
             ← the row the topological barrier is expected to enter
[22] ASM RD  4D multi-family box reduction (not written down)
[23] PRV HU  H↑ ⟸ [20][21][22]

How to check: on each "⟸" row, see by eye that the numbers on the right are smaller than the one on the left ([06] has [01][04][05], [07] has [03], [13] has [02], [15][16] have [14], [18] has [17], [23] has [20][21][22]). There are no circles. The "Assumption" leaves are the ten [01][02][05][11][12][17][19][20][21][22], the "Cited" leaf is [03], and the "Reading" leaf is [08].

Two things are read from this graph. First, the local H [12] enters nowhere in the chain that builds H↑ [23]. A reduction of the type of Proposition H3 uses closed boxes [21], whereas the boxes of the local H are open boxes. The local H is not a part of H↑ but a separate sentence. Where the local H is used is in the graph of the bridge in 11-04. Second, the place where H↑ is expected to break in four dimensions is concentrated in the single row [21]. The statement of [21] contains only the constant of closed boxes CboxC_{\rm box} and not the global CPC_P, so it is not of the form that puts the conclusion among the premises.

07

What cannot be said

(a) The two forms of H are candidate definitions; at no β\beta is there an inequality shown for the target gauge theory. What has been shown are properties of the definitions (Propositions 1 and 2) and values of the free-field reference. Nor do we claim "the right way to correct" H.

(b) The local H on the four-dimensional Wilson measure is a copy of the definition on the path measure in continuous time, and the existence of the infinite-volume measure [01] and the treatment of domains [05] are premise rows.

(c) The accounting for the charge of a subregion (transport in open boxes, barrier in closed boxes) is an estimate on top of cluster decay and the formal coefficients h,g,dh,g,d, with no four-dimensional lattice values.

(d) The four-dimensional multi-family box reduction [22] has not been written. The harm of sector walls, and how the sector H breaks when the physical volume is made large, are estimates.

(e) There is no evidence that the local H holds in four dimensions. There is only the accounting "freezing acts on the hh side, and the local H asks about dd".

(f) Every number in Table 1 is a number for the free field of the reference (one-colour Gaussian, β=1\beta=1, floating point, extrapolation); not a single ratio KrelK_{\rm rel} for the target measure has been measured. The threshold depends on the reference and on the family of test observables, and the bridge says nothing about fields in the band [K∗,1)[K_*,1) (11-04).

(g) "The ratio tends to 1 at short distance" is an assumption depending on asymptotic freedom; in the 0+1 double well this reading does not hold ((7)).


What this chapter can say

SaidNot said
Proved here The definition of the local Poincaré constant and Proposition 1 (a quantity of the marginal on the window, not dense, monotone, returns unconditionally to CPC_P as c→∞c\to\infty; in continuous time, on a finite spatial lattice, T=∞T=\infty, under the assumptions of Proposition B)The treatment of domains on the four-dimensional Wilson measure (the copy). The question of the core (identification with the generator of the SPDE)
Proved here The local H↑ in absolute form holds even for the massless free field on a box in four-dimensional spacetime, local in space too (K=c2K=c^2)That the local H↑ in ratio form holds for the target theory
Proved here That the family of plaquette functions and the gauge quotient coincide for contractible boxes; that gauge-fixed references depend on the parameter; the ratio for the shortest window ωb/m\omega_b/mReferences for SU(2)SU(2) at finite β\beta. Values for families of large four-dimensional loops
Reading Reference numbers Γ∞=0.0740\Gamma_\infty=0.0740, ΓQ,∞=0.0277\Gamma_{Q,\infty}=0.0277, λWQ=72.0\lambda_W^Q=72.0, 2.222.22 to 2.532.53 times with the boundary frozenNot propositions of upper or lower bounds. Numbers for free fields, not for the target measure
Proved here The definition of sectors (cuts at regular values, the reflecting form), finite ⟺ connected (on top of Rellich), the sandwich (10), corollary (11), the bridge inequality from sectorsWhether sectors are connected. Estimates of CtransC_{\rm trans}. The treatment of θ vacua
Estimate That the local H is expected not to be affected by freezing; that closed boxes are expected to inherit the barrier; that the sector H is expected to have meaning only in the order with the physical volume fixedNone of them is a theorem

Sources and reproduction

ItemKindSource / tools
Poincaré constant of a Gaussian measure = norm of the covarianceCitedLemma 2.2 of M. Hairer, A. M. Stuart, J. Voss, P. Wiberg (2005) (equality for linear functionals)
Autocorrelation of Q2Q^2 with open boundaries and the length in the time direction; the expected scaling of Langevin algorithmsCitedM. Lüscher, S. Schaefer, JHEP 07 (2011) 036 §5.3; M. Lüscher, S. Schaefer, JHEP 04 (2011) 104 §1 and footnote (text checked)
Proposition 1 (iii)(iv), (10) of Proposition 2, the algebra of (12), the ratio (7)LeanLatticeGauge.LocalH (local_le_global, local_approaches_global, sector_split, trans_le_total, transport_requirement), LatticeGauge.LocalHDoubleWell (one_slice_ratio). The bundles guarantee only suprema of sets of real numbers and algebra
Reference numbers of Table 1, Γ(R)\Gamma(R), r(mR)r(mR)ReadingLargest eigenvalue (Lanczos) of the compression to the box of the lattice Green function (numerical integration of the heat kernel), and an independent route via periodic lattices (removing the zero mode, extrapolation in 1/L21/L^2). The gauge quotient by two routes: projection via the Neumann Laplacian of the graph of the box, and projection via a dense singular value decomposition
Lattice ratios for the double wellReadingLattice eigenvalue problem for the transfer kernel (symmetric product with time step ε=12\varepsilon=\tfrac12)

Terms used in this chapter — the algebra of time-averaged functionals D\mathcal D, window, the local Poincaré constant CPloc(c)C_P^{\rm loc}(c), the ratio form KrelK_{\rm rel}, the massless reference and Γ\Gamma, the gauge-quotient reference, sectors and the reflecting form, the quantity between sectors CtransC_{\rm trans}, open boxes and closed boxes, the transport coefficient dd and the coefficient of breaking of conservation hh. The notation is in 11-A1.

Next chapter to read: 11-04 Which H the one-sided bridge needs — the threshold K∗K_* at which a lower bound on the gap comes out of the local H↑ in ratio form, and the size of box at which the bridge sees the mass.

← 11-02 Choosing the ruler and the coordinates again — the length at which conservation breaksContents11-04 Which H the one-sided bridge needs →

Revised 2026-10-09: first version.