Applications / Millennium problems

Collective geometry and the Yang–Mills gap

The Clay problem asks for a quantum Yang–Mills theory on the fixed Minkowski background ℝ⁴, with a unique vacuum of zero energy and a mass gap. FDT keeps the Einstein field equation, Gμν = κTμν, and has no background metric. On a fixed flat background Gμν ≡ 0, so the equation admits only a vanishing source, and the omnium has no empty state. If general relativity is ignored, the Clay problem statement does not apply to reality. The gap is posed on the physical domain instead: the step between the two lowest confinement eigenvalues of a closed pattern’s own region, where the one carrier stands.

The problem as posed

What the statement fixes, and the record

Jaffe and Witten state the problem for every compact simple gauge group 𝖦: prove that a non-trivial quantum Yang–Mills theory exists on ℝ⁴ and has a mass gap Δ > 0, existence including axiomatic properties at least as strong as those of Wightman or of Osterwalder and Schrader. The theory’s data are a Hilbert space carrying a unitary representation of the Poincaré group of Minkowski space (ℝ⁴, η); positive energy, 0 ≤ H, which the Wightman axioms state as the joint spectrum of energy and momentum in the closed forward cone; a vacuum Ω, Poincaré-invariant and unique up to a phase, with HΩ = 0; and the gap, no spectrum of H in (0, Δ) for some Δ > 0, the supremum of such Δ, the mass of the theory, finite.

The metric η is fixed. It enters through Poincaré covariance and is not a variable of the theory: the energy of the states varies while the geometry does not respond to it. The problem is posed with the response of geometry to energy switched off.

The classical record is settled on the same background. Klainerman and Machedon proved global well-posedness of the classical Yang–Mills evolution on Minkowski space for finite-energy data, and Oh gave a second proof through the Yang–Mills heat flow. The measured record has no massless strongly interacting state, and lattice gauge theory computes a glueball spectrum with no state at zero mass.

The problem statement’s data and the record the paper accepts, with the class of each entry. The cosmic microwave background enters as the floor the record exhibits in the observed domain (Section 6 of the paper).
ItemValueClass
Gauge groupevery compact simple 𝖦problem statement
BackgroundMinkowski (ℝ⁴, η), fixedproblem statement
VacuumPoincaré-invariant, unique up to a phase, HΩ = 0problem statement
SpectrumH ≥ 0; none in (0, Δ), Δ > 0; the mass finiteproblem statement
Classical evolutionglobal for finite-energy datatheorem (1995, 2015)
Hadron spectrumno massless strongly interacting statemeasured
Glueball spectrumno state at zero masscomputed on the lattice
CMB energy densityu = aT⁴ = 4.17 × 10⁻¹⁴ J m⁻³ at 2.7255 Kmeasured
CMB isotropy1.2 × 10⁻³ with the dipole, about 10⁻⁵ without itmeasured

The FDT reading

I-⁠3 The field equation kept, 0.1 no empty state, I-⁠5 the gap between confinement eigenvalues

A flat background holds only an empty source

FDT retains Gμν = κTμν unchanged, with κ = 8πG/c⁴ and Tμν the one total source of the omnium, every channel entering once (I-⁠3, 0.5). Clocks and rulers are closed patterns adjusting their own dimensions to keep the chain, so their adjustment is the geometry and no background metric lies beneath them (0.1a). Every configuration whose geometry is η therefore has

Gμν[η] ≡ 0 = κTμν⇒ Tμν ≡ 0 Theorem 2

Every state of the Clay theory off the vacuum carries energy. By the spectrum condition a state of zero energy is invariant under translations, so it is the vacuum, and every other state has E = ⟨ψ, Hψ⟩ > 0, gapped or not. That energy is a channel of the total gravitating energy, 𝓜 ≥ E/c², so Rs > 0 and αext(rf) = Rs/rf lies inside (0, 1) at every field radius: its geometry is not η. The vacuum has zero total source, ⟨Ω, TμνΩ⟩ = 0: E = 0 and m = 0, two variables of the chain that 0.1 never lets vanish, and Rs = 0, no fold and no branch of the atlas. It is the empty state, and the omnium does not have one. Read as an operator, its stress does not vanish, Tμν(f)Ω ≠ 0 for every nonzero stress smeared over a bounded region, and the vacuum then fails the field equation on η with every other state.

No state of the Clay theory, as posed on its fixed background, is therefore a physical configuration. The statement holds the metric fixed while the energy of its states varies; it ignores general relativity by construction. If general relativity is ignored, the Clay problem statement does not apply to reality (Theorem 5).

Families with the metric held fixed

Along a differentiable family z(s) of complete solutions of I-⁠3 the field equation differentiates to DG[ġ] = κṪ + κ̇T. With the physical metric held fixed and the constants of the core fixed, the total source cannot move at first or at second order (Theorem 7):

ġ = 0 ⇒ Ṫ = 0g̈ = 0 ⇒ T̈ = 0 at every point

This is the chain read as a constraint on families: when the energy of a pattern steps, the distances and durations it keeps step with it, and a family that changes the source while holding the metric fixed holds apart what the chain unifies. The constraint is on the total source, so channels compensate collectively at each point.

The pure-gauge interpolation is such a family. With θ = U⁻¹dU for a time-independent U, so that dθ + θ∧θ = 0, and A(s) = sθ on the fixed background in the temporal gauge, the field strength is F(s) = s(s − 1) θ∧θ and the Yang–Mills stress, quadratic in F at fixed metric and coupling, is

T(s) = 16 s²(s − 1)² T(½)Ṫ(½) = 0,  T̈(½) = −16 T(½) Proposition 9

Its magnetic energy has a maximum at s = ½, the barrier a fixed-background analysis reads between two pure-gauge configurations. The family never enters the physical domain. Wherever θ∧θ ≠ 0 its source is nonzero at every s strictly between its ends, which the flat background does not hold; its two ends, where F = 0, are the empty state. At s = ½ it also fails the second-order condition that a family of complete solutions with the metric held fixed passes. The negative second derivative is a property of the interpolation on its background and says nothing about the stability of the omnium: the family is no deformation of it, and the stability of a pattern is the ledger form of I-⁠5b, never the sign of a second variation (0.1a).

The pure-gauge interpolation on a fixed background. The solid curve is the Yang–Mills stress along A(s) = sθ in units of its value at s = ½, the dashed curve the field strength 4s(1 − s) in units of its own; the grey line is the one source a flat background holds, T ≡ 0. Move s: the teal tangent and dashed parabola show the first and second derivatives, and the readouts test the three conditions the field equation imposes on the family. The stress is nonzero at every s strictly between the open circles, where I-⁠3 fails before any derivative is taken; at the open circles F = 0 and the state is empty. At s = ½ the first derivative vanishes and the second does not; at the two inflections, marked ×, the second vanishes and the first does not. No s passes all three.

I-⁠3, 0.1

The second variation and the gap criterion

The core names no objective for the omnium’s optimisation; the paper reads one, as its own reading, through an energy functional 𝓔 (0.1a). On the coupled domain, its second variation along an admissible curve through a constrained stationary point carries the response of geometry, source, support and phase together with the curvature of the constraint surface (Lemma 8):

d²𝓔/ds² = D²(𝓔 − ⟨λ, 𝒞⟩)[u, u]

A Hessian that varies a gauge connection with everything else held fixed is the second variation of a different functional along a different family. Free relaxation over responding coordinates only lowers the form, by the Schur complement Q12Q22⁻¹Q12* ≥ 0 (Lemma 10): a positive frozen block decides nothing, and a negative one stays negative. A constraint adds the multiplier term −⟨λ, D²𝒞[u, u]⟩, whose sign is the curvature of the constraint surface, so the complete geometric response has no universal sign. What these forms bound is the spectrum of the generator of a closed pattern’s own region; the stability of a pattern is the ledger form of I-⁠5b.

The gap is then a uniform estimate on the generator of the internal dynamics of a closed pattern’s own region. With Hphys ≥ EbaseI, Ebase > 0 its lowest eigenvalue, Hrel = Hphys − EbaseI and P₀ the ground projection,

qrel[ψ] ≥ ε*‖(I − P₀)ψ‖²⇒ spec(Hrel) ∩ (0, ε*) = ∅ Proposition 11

In FDT the lower edge is a difference of confinement eigenvalues, ε* = ħ(ω₁ − ω₀) = ħω₁ − Ebase: the step from the lowest mode cost of a closed pattern’s own region, in which the one carrier stands, to the next (I-⁠2, I-⁠5), on the closure sector of I-⁠5a, which every transition keeps. Every mode cost is positive, so the gap is the step between the two lowest. The subtraction of Ebase changes the reference for differences and introduces no empty state: Ebase stays a channel of 𝓜. The confinement operator of the n = 3 closures, the class that carries colour, its domain and boundary data, and the estimate uniform over the admissible closures are to be derived (D-⁠1).

No empty region, and the infinite volume

An admissible region is a region of the physical spatial geometry that contains a ball of diameter dmin = 2ℓP; nothing below the floor is a region of anything (0.1a, 0.1b). Every admissible region holds omnium, whose energy is E = mc² with neither variable vanishing, so the energy measure has full support at admissible scales (Proposition 12). Full support alone gives no quantitative floor; the floor of the spacetime phase does, a positive infimum of its local density, to be derived from the omnium’s constitutive law (D-⁠3). The record exhibits it in the observed domain: the energy density of the substrate’s standing-wave state, u = aT⁴ = 4.17 × 10⁻¹⁴ J m⁻³ at 2.7255 K, fills that domain, its temperature the same in every direction to 1.2 × 10⁻³, the dipole, and to about 10⁻⁵ once the dipole is removed. A complete geometry of infinite volume is unbounded and holds infinitely many disjoint admissible regions, each carrying at least the floor e*, so it carries at least Ne* for every N:

μ(X) ≥ N e* for every N⇒ μ(X) = ∞ Theorem 13

On a geometry of infinite volume, the spatial ℝ³ of the Clay background, the energy measure of a configuration of the omnium is infinite, while the Clay vacuum assigns zero to every region. No subtraction of a finite constant carries the one to the other: the amount removed from each admissible region would be at least e*, and its total over the volume is infinite. The floor’s own window grows with the region: a ball of radius R holding at least u has

αext(R) ≥ κuR²/3   = 2.89 × 10⁻⁵⁷ (R/1 m)²

which reaches the seam αext = ½ at R = 1.32 × 10²⁸ m. A fixed flat background holds no part of this energy. The gap statement is posed on a closed pattern’s own region, a bounded support within a universal domain (0.8), where Ebase is finite and Hrel is defined.

The floor on the Clay background. Above: the least energy the floor puts in a ball of radius R, (4π/3)R³u with the measured u = aT⁴ at 2.7255 K, rising as the cube of the radius; the shaded region above the line is where the ball’s energy lies. The Clay vacuum assigns zero to every ball, below every point of the logarithmic axis. Below: the ball’s own window, read as its A-⁠1 odds Xext = Rs/(R − Rs), cobalt in the general-relativistic regime and brass in the quantum-mechanical one; the odds equal 1 at the seam αext = ½, reached at 1.32 × 10²⁸ m, and diverge where the bound reaches the fold, at 1.86 × 10²⁸ m. Move the radius or jump to a marked scale.

0.1, 0.3a, I-⁠3

The lowest pattern keeps time

Every pattern of the omnium has Eq = ħωq > 0 and keeps the period Tq = h/Eq, longer than tmin = 2tP: the thread it runs in that time is a physical stroke, and the floor bounds every stroke below (0.1a). A static pattern would have ωq = 0, a vanishing variable of the chain. The lowest pattern of a closed pattern’s own region cycles with period Tbase = h/Ebase (Proposition 15), and in the spectral representation it stays in its eigenspace while its phase advances by 2π in that time:

e−itHphys/ħΩ₀ = e−itEbase/ħΩ₀

That phase is the helical phase of I-⁠4. The Clay convention HΩ = 0 sets the period to infinity, a pattern that never completes a cycle, which is no pattern of the omnium. The energy accounting of an excitation therefore starts from a moving baseline: the excess is a difference of two complete configurations, each with its own geometry, network and every interaction counted once. Around every point the density is not uniform (0.1), so the lowest pattern carries the nodal architecture of P-⁠2, its density geodesics the channels along which its energy is transported. The self-consistent transport law of the lowest pattern and its network is to be derived (D-⁠2).

What FDT states

Commitments the record can end

The paper settles the domain on which the gap is posed. Its commitments are the core’s, read through the problem, each with the result that ends it; its open items are named.

  1. 0.1
    No massless strongly interacting state. The gap is the step between the two lowest confinement eigenvalues of a closed pattern’s own region (I-⁠2, I-⁠5), and the hadron spectrum has no massless strongly interacting state, as measured. A massless strongly interacting state ends this reading.
  2. I-⁠3
    Fixed-background results, recovered. For a laboratory configuration the coupled equations reduce to the fixed-background ones with corrections of relative size αext, 2.65 × 10⁻³⁹ for 1 GeV in 1 fm: the classical well-posedness theorems are recovered, and the glueball spectra computed on the lattice are tests for the operator of D-⁠1, never its outputs. A Yang–Mills observable departing from its fixed-background value far above that size, with the source counted in full, ends the reading.
  3. 0.8
    A floor in every region. Every admissible region carries energy, and in the observed domain the floor is exhibited by the substrate’s standing-wave state at u = aT⁴. A region of the observed domain found empty of energy ends the reading.
  4. D-⁠1
    The gap between confinement eigenvalues. The operator D of the n = 3 closures, the class that carries colour, its domain and boundary data, and the estimate uniform over the admissible closures, with the observable sector reaching the lower edge, are to be derived (D-⁠1, with the core’s O-⁠9, and O-⁠6 for the gluon octet’s dynamics).
  5. D-⁠2, D-⁠3
    The transport law and the floor’s value. The transport law of the lowest pattern with its density-geodesic network (D-⁠2) and the density floor of the spacetime phase with its value (D-⁠3) are to be derived.

Readings declined

Use 6 Data yes, interpretation not necessarily

Standard reading

The vacuum is empty space: the zero of energy, invariant under every translation.

FDT reading

The lowest state is the lowest pattern of the omnium on its own support, with Ebase > 0 entering 𝓜 once and sourcing curvature (0.1, 0.5, I-⁠3). Setting its energy to zero discards a gravitating channel, which only a background with its response switched off allows.

Minkowski space is the arena on which the field’s clocks and rulers are read.

Clocks and rulers are closed patterns adjusting their own dimensions to keep the chain; their adjustment is the geometry, and no background metric lies beneath them (0.1a).

Gluons are independent gauge quanta propagating on an empty background.

There is one carrier. The gluon is the stroke standing inside a closed pattern’s own region, held by topological closure, and the gap is the step between the two lowest costs of the closed region in which it stands (I-⁠2, I-⁠5).

Convergence

Use 2 Same source, same data

For the same source and data FDT and general relativity solve the same equation and return the same curvature (I-⁠3). A laboratory Yang–Mills configuration of 1 GeV in 1 fm has 𝓜 = 1.78 × 10⁻²⁷ kg, Rs = 2.65 × 10⁻⁵⁴ m and αext(1 fm) = 2.65 × 10⁻³⁹. At that order the coupled equations reduce to the fixed-background equations, and the classical well-posedness theorems are recovered as the αext → 0⁺ reading of the coupled solution, with the geometric response a correction of relative size αext. The masses of closed patterns are the confinement eigenvalues of D-⁠1, whose operator is the core’s register item O-⁠9: the glueball spectra computed in lattice gauge theory are tests for it, never its outputs. The measured record, a hadron spectrum with no massless strongly interacting state, is accepted in full.

What FDT declines is the endpoint Rs = 0: the exactly flat background and the exactly empty vacuum of the problem statement, the endpoint of the one-sided limit αext → 0⁺, which no configuration attains (I-⁠6). The Clay statement poses pure Yang–Mills for every compact simple gauge group; in FDT the carrier stands only inside a closed pattern’s own region, and colour is the SU(3) of the internal nodal surface of the n = 3 closures (I-⁠2, I-⁠5): the physical gap problem is posed there. Where FDT, general relativity and quantum mechanics converge, FDT reproduces their results; where it declines their assumptions, here the fixed background and the empty vacuum, it is under no obligation to reproduce them.