The whole book Contents and reading orders
- Part 0 Entrance — how to read this book
- 0-01 How to read this book
- 0-02 One picture
- 0-03 Reading the problem statement word by word
- 0-04 Four dimensions in mathematics and four dimensions in physics
- Part 1 Mathematical preparation
- 1-01 Vector spaces and linear maps
- 1-02 What a group is
- 1-03 Lie groups and Lie algebras
- 1-04 SU(2) and SU(3)
- 1-05 Manifolds and tangent spaces
- 1-06 Differential forms and the exterior derivative
- 1-07 Vector bundles and connections
- 1-08 Probability and measure
- 1-09 Probability in infinite dimensions
- 1-10 Hilbert spaces and self-adjoint operators
- 1-11 Fourier analysis and distributions
- 1-12 Detour: what happens only in four dimensions
- Part 2 Physical preparation
- 2-01 Lagrangians and the action
- 2-02 The idea of a field
- 2-03 Electromagnetism is a gauge theory
- 2-04 Special relativity and spacetime
- 2-05 The bones of quantum mechanics
- 2-06 The harmonic oscillator and creation and annihilation
- 2-07 The idea of the path integral
- 2-08 Statistical mechanics and phase transitions
- 2-09 Detour: the gap and the correlation length in the Ising model
- 2-10 The relaxation time and the dynamical exponent z
- Part 3 Yang–Mills theory (classical)
- 3-01 The gauge principle
- 3-02 Non-abelian gauge fields
- 3-03 The action and the equations
- 3-04 Gauge theory as geometry
- 3-05 Instantons and topology
- 3-06 Detour: Donaldson and exotic R⁴
- 3-07 Yang–Mills inside the Standard Model
- Part 4 Quantisation
- 4-01 Canonical quantisation and the Hamiltonian
- 4-02 The path integral and Euclideanisation
- 4-03 Perturbation theory and Feynman diagrams
- 4-04 Divergences and renormalisation
- 4-05 The algebra of divergences
- 4-06 Asymptotic freedom
- 4-07 Dimensional transmutation and Λ
- 4-08 Gauge fixing and Faddeev–Popov
- 4-09 The axioms of quantum field theory
- 4-10 The Osterwalder–Schrader axioms and reconstruction
- 4-11 The definition of the mass gap
- 4-12 Detour: the perturbation series diverges
- Part 5 Lattice gauge theory
- 5-01 Wilson's lattice
- 5-02 The strong-coupling expansion
- 5-03 Reflection positivity and the transfer matrix
- 5-04 The infinite-volume limit and the cluster expansion
- 5-05 Weak coupling and the continuum limit
- 5-06 How U(1) differs from the non-abelian case
- 5-07 The Monte Carlo method
- 5-08 Measuring glueballs and the string tension
- 5-09 What to hold fixed when taking the limit
- 5-10 Lattice gauge theory with finite groups
- 5-11 Detour: Bakry–Émery and one-link integration
- Part 6 Constructive field theory
- 6-01 What constructive field theory is
- 6-02 Solvability in two dimensions and the Yang–Mills measure
- 6-03 Constructing scalar fields
- 6-04 The cluster expansion
- 6-05 The sequence of renormalisation group steps
- 6-06 Ultraviolet stability of three-dimensional Yang–Mills
- 6-07 Four dimensions
- 6-08 Triviality of φ⁴ in four dimensions
- 6-09 Stochastic quantisation and regularity structures
- 6-10 Where four dimensions stops
- 6-11 Obstacles other than divergence
- 6-12 Detour: "if 1/0 is given a symbol"
- Part 7 From the side of physics
- 7-01 How physics sees it
- 7-02 Mechanisms of confinement
- 7-03 The string picture
- 7-04 Large N
- 7-05 String theory and extra dimensions
- 7-06 How extra dimensions become invisible
- 7-07 Where gauge fields come from
- 7-08 Holography
- 7-09 The mass gap becomes geometry
- 7-10 Back to four dimensions
- 7-11 Supersymmetry and Seiberg–Witten
- 7-12 The sentence that plays the role of an equivalence principle
- 7-13 Where the way physics digs parts from mathematics
- Part 8 A dictionary of two languages — the physical and the mathematical view
- 8-01 How to read the dictionary
- 8-02 Dictionary A
- 8-03 Dictionary B
- 8-04 Dictionary C
- 8-05 The physical counterparts of our assumptions
- Part 9 Where things stand, and open tasks
- 9-01 How far the world has come
- 9-02 Where the two ways of digging part
- 9-03 Candidates for new concepts
- 9-04 The list of open tasks
- 9-05 Common misconceptions
- Part 10 Towards a proof of the mass gap — building the first step of the staircase
- 10-00 Entrance — the staircase, and the random walk, the ruler and the clock
- 10-01 The line of construction and Assumption H
- 10-02 Roads tried on the four-dimensional lattice, and walls
- 10-03 The four steps of the staircase — why we start from 0+1 dimensions
- 10-04 The path measure of the double well, and kinks
- 10-05 The statement of the first step — four conditions and Proposition 4.5
- 10-06 (H1) Local Poincaré within a phase
- 10-07 The map of (H2) — seven routes and the seam of the ring
- 10-08 What computer-assisted means — the conditions on the chain inside the window
- 10-09 The sector framework and the three strands of route 5
- 10-10 The list of detour plans — types of breakage
- 10-11 (H3)(H4) and the constant of the core
- 10-12 The integrated table and the dependency graph
- 10-13 Lean statements and the limits of machine checking
- 10-14 Reconciliation — the numbers of the record and the known numbers
- 10-15 What remains and its cost — the distance to a theorem
- 10-16 What is not claimed
- 10-17 Insights and small questions
- Part 11 Further considerations — beyond Assumption H, and other views
- 11-00 Further considerations — entrance
- 11-01 One form that obstructs H — a nearly conserved global quantity
- 11-02 Choosing the ruler and the coordinates again — the length at which conservation breaks
- 11-03 Two ways to repair H — the sector H and the local H
- 11-04 Which H the one-sided bridge needs
- 11-05 Making time continuous — the Hamiltonian lattice and the vacuum measure
- 11-06 Paying with rarity instead of convexity — renormalisation on groups and log-Sobolev
- 11-07 Because it is four dimensions — the dimensionless coupling and topology
- 11-08 Questions, and what is not claimed
- 11-A1 Table of notation for Part 11
- Appendices
- A-01 Table of notation
- A-02 Glossary
- A-03 Guide to the literature
- A-04 Lean and machine checking
- A-05 How this book was made
- 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 over functionals supported in a window of length ; it is fixed by the marginal law on the window alone, and returns unconditionally to the global as . But the form " for some " holds even for the massless free field and is empty, so it must be stated by the ratio 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, , 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 , and the global H about the coefficient of breaking of conservation .
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 ). 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 . 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.
- Summary — a section readable at [Y3]
- Definition of the local H — the algebra of time-averaged functionals , the window families , Proposition 1 ((1)–(4))
- The ratio form and the gauge-quotient reference — the emptiness of the absolute form, , gauge-invariant references, the note on 0+1 ((5)–(7), Table 1)
- The sector H — cuts at regular values, the reflecting form, Proposition 2 and the sandwich, three weaknesses ((8)–(11))
- Open boxes and closed boxes, two coefficients — local asks , global asks , Table 2 (the order of volume and )
- Table of the five grades — Table 3 / dependency graph
- What cannot be said
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 , 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 (in four dimensions, a spacetime box of side ). is a ruler given from outside, independently of the gap; in four dimensions it is the bookkeeping length . The supremum is fixed by the marginal distribution on the window alone, increases monotonically as the window widens, and returns exactly to the global as . But in a four-dimensional box, is finite, of order the square of the side of the box, even for the massless free field. Merely satisfying "" says nothing, so we ask that the ratio 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 is sandwiched: above by the sum of "the worst constant within a sector" and "the quantity between sectors ", and below by . Assuming the sector H, H↑ becomes the same as . 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 not to be too small, and the global H↑ needs the coefficient of breaking of conservation of the charge not to be too small. In four dimensions, the freezing of the topological charge acts on the 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.
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 (a finite-dimensional connected Riemannian manifold with metric ), with assumption (A1) (discrete spectrum, simple ground state , ), the stationary path measure with (one-time distribution , transition , ), and . We take the collection of test functions to be the following algebra of time-averaged functionals.
Here , (up to polynomial growth for ), and the weights have bounded support. , and the metric satisfies (A3) of Proposition B. The global Poincaré constant is defined as over . The test functions of Proposition B, , belong to this .
For a ruler of length and , put the window and
is not the length fixed by the gap, , but a length given from outside (in four dimensions, the bookkeeping length ).
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 gives the same value).
(i) is fixed only by the marginal law of the path on the window, , and the Dirichlet form inside the window.
(ii) is not dense in .
(iii) If , then .
(iv) . This limit needs no assumption.
Proved here Proof. (i) is fixed only by the values of the path inside the window (the path is continuous, and is the limit of Riemann sums over points inside the window). For , , so , and both the variance and the Dirichlet form are expectations under the marginal law on the window.
(ii) The closure of lies in , the space of functions measurable with respect to the -algebra generated by the path inside the window. The value at a time outside the window ( non-constant) is not measurable with respect to : with the distance from the end of the window, the conditional expectation is of the form , which under (A1) does not coincide with itself.
(iii) If , then , and the supremum over a subset is smaller.
(iv) The weights in have bounded support, so taking the window as by stationarity, . If , there is whose ratio exceeds , and that lies in for some , so . Together with the monotonicity of (iii), the limit is . ∎
Lean LatticeGauge.LocalH.local_le_global (assumptions: bounded above, non-empty, subset) and local_approaches_global (assumptions: , bounded above, non-empty; conclusion: every smaller than is exceeded by for some ) check only the part of (iii)(iv) about suprema of sets of real numbers. The path measure, and are outside Lean.
(iv) holds without assumptions because was defined over . 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 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 is , 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.
(left: the power statement for families with ; right: the absolute form of its upper half). Two things follow in one line from Proposition 1 Proved here. First, the global H↑ implies with the same constant for every ((iii)). Second, if holds for every with a uniform in , 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 fixed.
A version local in space too. On an infinite spatial lattice (or a spatial lattice containing the box), take the product of a spatial box and a window, and define in the same form the family , with restricted to single-time functions depending only on variables in , and . (i)–(iv) of Proposition 1 hold with the same proof, and the marginal in (i) is the law of the field on . The local H on the four-dimensional Wilson measure copies this definition onto a spacetime box of side (), treating time and space alike, and the -algebra generated by the links in the box; the Dirichlet form is that of link Langevin, . What is presupposed at the copying stage is the existence and uniqueness of the infinite-volume Wilson measure ((S1) of Part 10) Assumption.
The ratio form and the gauge-quotient reference
The absolute form is empty. The right-hand form of (3), , holds on a four-dimensional spacetime box, local in space too, even for the massless free field. Writing for the local Poincaré constant of the infinite-volume massless free scalar field (one component, canonical graduation) on a spacetime box of side ,
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 . In four dimensions is finite (transient) and its kernel is continuous, of the type , so the Schur estimate gives the upper side, and the value with the Dirichlet ground state of the box as test function gives the lower side. Hence, reading , holds with , and the form " for some " says nothing about the gap. This is the negative control of this definition (the massless free field). In numbers, is at ; the correction is with no logarithmic correction, and Reading (floating point, numerical integration of the heat kernel on the infinite lattice, extrapolation from ; within relative of an independent route via periodic lattices). The massless field itself satisfies .
One line of contrast with lower dimensions. For massless fields in two spacetime dimensions the infrared diverges and ; localising only to a time window on a finite spatial lattice, the constant mode gives (), which diverges as . 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.
Put the ratio of the local Poincaré constant of the target measure (the Wilson measure, or the path measure in continuous time) on the box to the value of the massless reference with a Dirichlet form on the same lattice, the same box and the same graduation as
The local H↑ is this sentence at a single ; it is not required uniformly in .
It corresponds to the constant of the absolute form by Proved here. In the ratio form the constant becomes an absolute number independent of the box size, and "sufficiently smaller than 1" has meaning.
Why it is not required uniformly in . For the free field of mass the ratio is a function of alone, , and is at Reading (agreeing within for boxes of side to ). When the box is smaller than the correlation length () the ratio tends to 1. An asymptotically free theory is close to a free field at short distance, so a sentence requiring uniformly down to is expected to be false Estimate. For a field whose action is a convex perturbation ( convex), the Brascamp–Lieb inequality gives 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 , and the threshold moves with the choice of reference: (scalar), (gauge quotient, one-colour linearisation), (colour singlet of , leading term). The threshold, and that the band 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.
If the box is contractible, 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), . Gauge-fixed references (Feynman gauge and so on) depend on the fixing parameter , with , and moreover , so they become infinite as (removing the fixing) Proved here. The numbers are in Table 1.
| Reference | Test space | As a reference | ||
|---|---|---|---|---|
| Scalar (one component) | All functions on the box | Reading | Not used for gauge fields | |
| Feynman gauge () | All functions of the links of the box | Reading | Depends on ; not intrinsic | |
| Gauge quotient | (functions of plaquette angles) | Reading | Reading | Independent of . This one is used |
| Variant with the boundary gauge frozen | Divided only by gauge transformations at inner sites | to times the gauge quotient (side to ) 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 to . 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 ). The reference always has a scale, and for the double well we take the harmonic oscillator with the curvature of the bottom (angular frequency ). Its ratio for the shortest window (a single time) is exactly (when is the Schrödinger ground state) Proved here:
( is the time step. The numerator is the Poincaré constant of the marginal , which moves to the gap of 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: ; only the algebra of the ratio). In the double well, tunnelling gives , so the ratio does not become 1 even for short windows; on the lattice it is () to () 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.
The sector H
Setting. Take the periodic box , the configuration space (a compact connected manifold with a bi-invariant metric), the Wilson measure (smooth positive density), and . For the topological charge we use the lattice charge smoothed by the Wilson flow (flow time ) or by finitely many smoothings. The smoothing map is smooth and the charge density is a polynomial in matrix elements, so .
Take the cuts at regular values of (by Sard's theorem almost all values are regular, so they can be taken arbitrarily close to ).
(only for with ). No boundary condition is imposed on . 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 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.
(i) is connected.
(ii) With the sector index, for smooth ,
(iii) For the quantity between sectors ,
(iv) 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 ; the right uses the Poincaré inequality in each sector on the first term of (9) and closes with . (iv) Functions on sectors may jump at the walls (they are not in ), so if conditioning creates a new bottleneck, is possible. ∎ Lean LatticeGauge.LocalH.sector_split (assumptions: weights , the inequality in each sector, the two formulas of (9), ; conclusion: the right of (10)), trans_le_total (assumptions: weights and sector variances , (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.
Proved here (from (10); is up to replacing constants). The sector H pushes the obstruction to H exactly into the quantity between sectors . 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 is the rate of dislocations, and statically .
It does not connect to the bridge. What follows from (10) and the one-sided bridge ((17) of 10-01, with corrections for finite in periodic time) goes only as far as , and no gap comes out unless is bounded Proved here. The Langevin gap within a sector, , is a fifth quantity of time, and the conditioned measure 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 fixed and , the charge of a half box can move even within a sector . With the coefficients of (5) in 11-01, the conditional variance is of order and the Dirichlet form of order , and the ratio tends to as , the same order as the overall ratio of the periodic box Assumption (on the definitions of 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 has no sectors. The four-dimensional charge is a quantity integrated over time, and for it is not in .
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 ((14) of 10-04 Assumption), and fits into the power form of H. The four-dimensional quantity between sectors is exactly a quantity of the pattern of 11-01, and there is no prospect yet that it fits into the same form.
Open boxes and closed boxes, two coefficients
Local asks about the transport coefficient; global asks about the coefficient of breaking of conservation. The charge in a smooth window of (7) in 11-01 belongs to the local family of a box of side . Putting (7) into the local H↑ (absolute form), the necessary condition is , and in the regime where is small (the crossing length much longer than ),
Proved here (algebra) Lean LatticeGauge.LocalH.transport_requirement (assumptions: , , ). In the ratio form, is read as . On the other hand, the necessary condition for the global H↑ is (2)(6) of 11-01 with ,
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 , and the global H about the coefficient of breaking of conservation of the charge . The freezing of the four-dimensional topological charge can be read as the appearance of 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 and .
Closed boxes and open boxes. Proposition H3 of Part 10 (10-11 §02) is a reduction bounding the global by a box constant , and was the constant of a conditioned measure with the boundary values fixed (with 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 , 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 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".
| Order | Taken first | Corrections expected to work | Corrections expected not to work | Label |
|---|---|---|---|---|
| with the physical side fixed | Continuum limit of a finite box | Open boundaries, the sector H | — | Cited (original sources on open boundaries), Estimate |
| Volume to infinity first (the order of this book) | Infinite-volume lattice measure | The local H (open boxes) | Open boundaries, the sector H | Assumption (accounting for the charge of a subregion), Estimate |
The original source writes that the scaling of the autocorrelation of algorithms implementing Langevin ( 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.
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.
| Row | Statement (one line) | Grade | Grounds | Scope | Machine checking |
|---|---|---|---|---|---|
| S1 | Existence and uniqueness of the infinite-volume Wilson measure | Assumption | (S1) of Part 10 | — | |
| RL | Rellich's theorem (compactness of the Neumann resolvent) | Assumption | Proposition 2 (i) (the statement in the original source has not been checked) | Smooth boundary | — |
| GP | Poincaré constant of a Gaussian measure = norm of the compressed covariance | Cited | (4), Hairer–Stuart–Voss–Wiberg 2005 | Gaussian | — |
| L1 | Proposition 1 (i)–(iv) | Proved here | Proof in §02 | Continuous time, finite spatial lattice, | local_le_global, local_approaches_global (assumptions: bounded above, non-empty, ; only the supremum part) |
| W4 | That the proof of Proposition 1 goes through in the same way for boxes of the four-dimensional Wilson measure | Assumption | End of §02 (the treatment of domains is not written out) | Four dimensions, infinite volume | — |
| LD | Properties of the four-dimensional local Poincaré constant | Proved here | On S1, L1, W4 | Four dimensions | — |
| VC | The absolute form holds with for the massless free field | Proved here | (4) | Four-dimensional spacetime, local in space too | — |
| GM | , , , to times with the boundary frozen | Reading | §03, Table 1 | Free field, one-colour Gaussian, , | — |
| GQ | in contractible boxes; gauge-fixed references depend on and diverge as | Proved here | (6) | Contractible box | — |
| OS | Ratio for the shortest window | Proved here | (7) | 0+1, Schrödinger | one_slice_ratio (assumptions: ) |
| AF | The ratio tends to 1 at short distance | Assumption | The note on 0+1 in §03 (depends on asymptotic freedom) | Four dimensions | — |
| HR | Local H↑ (ratio form): at a single | Assumption | (5) | — | |
| P2 | Proposition 2 (i): sector constant finite ⟺ sector connected | Proved here | §04 (on top of RL) | Periodic box, cuts at regular values | — |
| SW | The sandwich (10) | Proved here | (9)(10) | Periodic box | sector_split, trans_le_total (assumptions: weights , the inequality in each sector, the two formulas of (9)) |
| CO | Corollary (11): under the sector H, H↑ ⟺ | Proved here | (11) | Box with fixed physical side | — |
| NB | What comes out of sectors goes only as far as | Proved here | §04 (on top of Proposition B) | Finite box | — |
| CL | Cluster decay (CL of 11-01) | Assumption | (5) of 11-01 | Infinite volume | — |
| TR | (12): local asks ; (13): global asks | Proved here | (12) (algebra), (13) on top of CL | Four dimensions | transport_requirement (assumptions: ) |
| HB | Ratio for half boxes within a sector | Assumption | Weakness (b) of §04 | with fixed | — |
| MX | (MIX4) maximal correlation between families of closed boxes, uniform in | Assumption | Premise of the four-dimensional version of Proposition H3 | Four dimensions, families of colours | — |
| BX | (BOX4) for closed boxes | Assumption | §05 (the row where the topological barrier is expected to enter) | Four dimensions | — |
| RD | Four-dimensional multi-family box reduction | Assumption | Four-dimensional version of the one-dimensional Proposition H3 (not written out) | Four dimensions | — |
| HU | H↑ | Proved here | Algebra on top of MX, BX, RD | Four 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 and not the global , so it is not of the form that puts the conclusion among the premises.
What cannot be said
(a) The two forms of H are candidate definitions; at no 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 , 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 side, and the local H asks about ".
(f) Every number in Table 1 is a number for the free field of the reference (one-colour Gaussian, , floating point, extrapolation); not a single ratio 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 (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
| Said | Not 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 as ; in continuous time, on a finite spatial lattice, , 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 () | 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 | References for at finite . Values for families of large four-dimensional loops |
| Reading Reference numbers , , , to times with the boundary frozen | Not 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 sectors | Whether sectors are connected. Estimates of . 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 fixed | None of them is a theorem |
Sources and reproduction
| Item | Kind | Source / tools |
|---|---|---|
| Poincaré constant of a Gaussian measure = norm of the covariance | Cited | Lemma 2.2 of M. Hairer, A. M. Stuart, J. Voss, P. Wiberg (2005) (equality for linear functionals) |
| Autocorrelation of with open boundaries and the length in the time direction; the expected scaling of Langevin algorithms | Cited | M. 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) | Lean | LatticeGauge.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, , | Reading | Largest 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 ). 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 well | Reading | Lattice eigenvalue problem for the transfer kernel (symmetric product with time step ) |
Terms used in this chapter — the algebra of time-averaged functionals , window, the local Poincaré constant , the ratio form , the massless reference and , the gauge-quotient reference, sectors and the reflecting form, the quantity between sectors , open boxes and closed boxes, the transport coefficient and the coefficient of breaking of conservation . The notation is in 11-A1.
Next chapter to read: 11-04 Which H the one-sided bridge needs — the threshold 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 →