Current–Metric Locking and the Topological-Current Non-Protection Lemma
A record of the derivation: the sharpened condition for structural g = 2, the explicit failure of the metric-independent topological current, the profile-preserving deformation that closes the route, and the boundary of what remains open.
How to Read This Document
This is a record of a sustained derivation. It begins from a single structural condition — the relation Mκ = Λ implied by g = 2 — and ends with a clean negative result about the topological-current route and a sharp statement of the remaining open problem. The document labels every claim: proved, derived, conditional, ruled out, or open.
| Label | Meaning |
|---|---|
| Proved | Fully established by an explicit construction or a closed argument. |
| Derived | Follows from a calculation under stated assumptions. |
| Conditional | Holds only under assumptions that have not been verified in general. |
| Ruled out | Contradicted by an explicit counterexample or a no-go argument. |
| Open | No calculation has settled it. |
| Corrected | An earlier claim in the derivation that was found to be wrong. |
Part I — The Sharpened Condition
From Mκ = Λ to Current–Metric Locking
The starting point is structural g = 2 for a charged rotating soliton. In collective-coordinate language, the magnetic moment κ and the moment of inertia Λ satisfy
M κ = Λ
The structural g = 2 condition.
This is equivalent to a mixed-response statement. Writing the energy as
E(B, Ω) = M + ½ Λ Ω² − q κ Ω·B + ⋯
the condition becomes
∂²E/∂Ω_i∂B_j |₀ = −(q/M) ∂²E/∂Ω_i∂Ω_j |₀
This is a statement about the source-dependent soliton energy. It is not yet a statement about the microscopic theory. The sharpening is to ask what this requires of the moduli-space geometry.
Structural g = 2 requires current–metric locking: the electromagnetic magnetic-response one-form must equal the metric dual of the rotational Killing vector, up to q/M.
Θ_EM^i = (q/M) K_i^♭
This is much stronger than Mκ = Λ alone. It identifies a specific one-form on moduli space and demands that it be fixed by the rotational Killing vector. Nothing about topology, Bogomolny saturation, or Kähler geometry alone forces this identification.
Part II — The Topological-Current Route
The Metric-Independent Topological Current
The most natural candidate for a bosonic mechanism is a soliton whose electromagnetic current is a conserved topological current:
J_EM^μ = q_t B^μ, ∂_μ B^μ = 0
B^μ is the degree current of the SU(2) hedgehog.
If this is the whole story, then the electromagnetic response one-form Θ_EM is determined entirely by B^μ, independently of the kinetic sector of the theory. The question is whether topology can protect the locking condition.
The Off-Shell Test
For the SU(2) hedgehog with unit winding, the topological density B⁰(r) satisfies
4π ∫₀^∞ r² B⁰(r) dr = 1
Topology fixes the normalization.
But the magnetic first moment involves an extra factor of r²:
μ_top = (q_t/3) ⟨r²⟩_B Ω
⟨r²⟩_B = ∫ r² B⁰(r) d³x
The normalization integral ∫ B⁰ d³x is topological. The first moment ∫ r² B⁰ d³x is not. It depends on the profile of B⁰(r), and therefore on the soliton shape.
This is the first indication that the topological-current route cannot work by topology alone.
Part III — The Measure Mismatch in BPS Skyrme
BPS Skyrme
The BPS Skyrme model is the most favorable bosonic soliton to test: it has a first-order Bogomolny equation and a Bogomolny bound. Its Lagrangian is
ℒ_BPS = −λ²π⁴ B_μ B^μ − μ² V(U)
Squared baryon current plus a potential.
On a BPS solution the two terms are pointwise equal, so the static mass is
M = 2 λ² π⁴ ∫ ρ_B² d³x
The rotational inertia is obtained by rigidly rotating the density:
Λ = (4/3) λ² π⁴ ∫ r² ρ_B² d³x
Meanwhile the topological magnetic moment is
𝒦 = (q_t/3) ∫ r² ρ_B d³x
The Missing-Half Condition
The proposed identity for the topological contribution is
𝒦 = (q/2) (Λ/M)
Substituting the BPS expressions gives
q_t ⟨r²⟩_{ρ_B} = q ⟨r²⟩_{ρ_B²}
Two different moments of the profile.
The left side is the mean-square radius weighted by baryon density. The right side is the mean-square radius weighted by squared baryon density. These are different functionals of the profile.
Even for the maximally favorable case of a uniform density inside a ball, the two moments are equal, not in the ratio required by the missing-half condition. And the BPS equation does not enforce the ratio for a generic potential.
Bogomolny saturation of the BPS Skyrme model does not, by itself, enforce the topological missing-half condition. The potential remains a deformation direction inside the BPS class, and it changes the two moments differently.
Part IV — Failed Deformation Candidates
The Strategy
The route forward is to construct an explicit profile-preserving deformation: a local, Lorentz-invariant, symmetry-preserving operator that
𝒪_*[φ₀] = 0, δ_static 𝒪_*[φ₀] = 0, δ²_Ω 𝒪_* ≠ 0
Such an operator leaves the static soliton and its mass unchanged to first order, while changing the rotational kinetic metric. If it does not couple to A_μ, it also leaves the topological current unchanged. Then D𝒞 ≠ 0, and the topological-current route is closed.
First-Derivative No-Go
The first candidate class is algebraic functions of the Gram tensor
X_{μν} = −½ Tr(L_μ L_ν)
For a static configuration, X_{00} = 0 and X_{0i} = 0. Under a rotation, X_{0i} = O(Ω), but the linear variation of any trace invariant vanishes because X^(0) has no temporal row or column.
No smooth Lorentz scalar constructed algebraically only from X_{μν} can satisfy F[U₀] = 0 and δ_rot F ≠ 0 for a static SU(2) configuration.
Failed Higher-Derivative Candidates
| Candidate | Reason it fails |
|---|---|
| W = ε^{μνρσ} Tr(L_μ L_ν L_ρ L_σ) | Vanishes identically for SU(2): four one-forms in a three-dimensional Lie algebra. |
| (B^μ ∂_μ B²)² | On the spherical rotor, B^i ∂_i B² = 0 because the rotation is tangential to level surfaces of B². |
| B^μ B^ν Tr(∂_μ L_ν) | Identically zero: Tr(L_ν) = 0. |
| (Tr(L_μ L_ν) ∂^μ B^ν)² | Vanishes at O(Ω²) on the hedgehog by symmetry of X_ij and antisymmetry of ∂_i v_j. |
All these failures share a common geometric origin. For a spherical hedgehog, the rotation velocity v = Ω × x is tangential, and every invariant radial vector is proportional to n. The contraction v·n vanishes. Meanwhile the only invariant rank-two spatial tensor is symmetric, so it cannot contract with the antisymmetric rotation gradient.
Part V — The Profile-Preserving Deformation
The Surviving Operator
The obstruction is broken by using the derivative of the topological current, not the current itself. Define
𝒪_B = B^μ B^ν Tr(∂_μ L_α ∂_ν L^α)
L_α = U^{-1} ∂_α U.
This operator is local, Lorentz invariant, and symmetry preserving. It does not couple to A_μ.
Static Properties
The Rotor Matrix Element
Under a rigid rotation, the convective derivative 𝒟 = ∂_t + v·∇ annihilates the field itself, but it rotates the spatial covector index of L_i:
𝒟 L_i = −(∂_i v^j) L_j = −ω_i^j L_j
This surviving term gives the quadratic rotor matrix element. After angular integration,
∫ d³x 𝒪_B^(2) = (16π/3) Ω² ∫₀^∞ dr r² ρ(r)² (f’² + 2 sin²f / r²)
The quadratic rotor matrix element is strictly positive for a nontrivial B = 1 hedgehog. The operator changes the rotational kinetic metric.
No Electromagnetic Response
Because 𝒪_B does not couple to A_μ, and because the topological current J_EM^μ = q_t B^μ is unchanged at linear order, the electromagnetic magnetic-response one-form Θ_EM is unchanged:
δ Θ_EM = 0, δ K^♭ ≠ 0
Therefore, if 𝒪_B is nonredundant, D𝒞 ≠ 0 and the topological-current route is closed.
Part VI — The Non-Redundancy Test
The Redundancy Question
An operator can fail to change the physics if it is a total derivative, proportional to the equations of motion, or removable by a field redefinition. The question is whether
𝒪_B = E_A Y^A + ∂_μ V^μ
for some local Y^A, V^μ.
The On-Shell Test
Evaluate on the true adiabatic rotating solution
φ_Ω = φ₀ + Ω Z_rot + Ω² η₂ + ⋯
Because 𝒪_B[φ₀] = 0 and D𝒪_B[φ₀] = 0, the quadratic matrix element is determined entirely by the rotational zero mode. The centrifugal correction η₂ does not contribute.
Suppose for contradiction that 𝒪_B = E_A Y^A + ∂_μ V^μ. On-shell, E_A = 0, so
𝒪_B = ∂_μ V^μ
Integrating over a closed rotational period T:
∫₀^T dt ∫ d³x ∂_μ V^μ = [∫ d³x V⁰]₀^T + ∫₀^T dt ∮_∞ dS_i V^i
The spatial boundary term vanishes by localization. The temporal term vanishes for a single-valued local V⁰ over a closed orbit. Therefore redundancy would imply
∫₀^T dt ∫ d³x 𝒪_B = 0
But the explicit matrix element gives TC Ω² + O(Ω³), which is nonzero for sufficiently small nonzero Ω.
Contradiction. Therefore 𝒪_B is not in the ideal generated by the equations of motion and total derivatives.
𝒪_B ∉ ⟨E_A⟩ + dΩ³_loc
Part VII — The Result and Its Boundary
The Lemma
For an SU(2) hedgehog whose electromagnetic coupling is supplied by a metric-independent topological current B^μ, current–metric locking cannot be protected solely by topology against arbitrary local Lorentz- and symmetry-preserving EFT deformations.
The proof is constructive. The operator 𝒪_B = B^μ B^ν Tr(∂_μ L_α ∂_ν L^α) is local, symmetry-preserving, vanishes on every static configuration, has vanishing first static variation, has a strictly positive quadratic rotor matrix element, and is nonredundant by the closed-orbit on-shell argument.
The Stated Assumptions
| Assumption | Role |
|---|---|
| U is neutral under the electromagnetic U(1) | Ensures the deformation does not induce an explicit A_μ dependence. |
| J_EM^μ = q_t B^μ | Defines the metric-independent current. |
| Adiabatic on-shell expansion is valid | Justifies evaluating on the slowly rotating solution. |
| Standard locality and falloff | Ensures the boundary terms vanish. |
The Boundary
If U is charged under the electromagnetic U(1), the deformation may acquire explicit A_μ dependence through covariant derivatives. Then δΘ_EM need not vanish, and the argument does not directly apply. This is the common-generating-structure class.
Addendum I — The Odd-Ω Lemma
Why F² Constructions Fail
Every attempt to construct a profile-preserving deformation as 𝒪_* = F² with F[U₀] = 0 and F[U_Ω] = O(Ω) fails for a structural reason.
For a spherically symmetric hedgehog, the integrated action has no term linear in Ω. The energy is even in Ω, and the first nontrivial term is the quadratic moment of inertia.
The proof is simple. The only invariant vector available is r̂. Any term linear in Ω must be of the form Ω·r̂ f(r), and the angular integral vanishes. Therefore F[U_Ω] starts at O(Ω²), and F² starts at O(Ω⁴) — too high order to affect the quadratic kinetic metric.
Searching for F = O(Ω) is the wrong strategy. The correct target is a direct O(Ω²) operator satisfying 𝒪_*[U₀] = 0, δ_static 𝒪_*[U₀] = 0, and 𝒪_*[U_Ω] = c(r) Ω² + O(Ω⁴).
Addendum II — The Local Response Identity
The Next Theorem
The remaining question is independent of the topological-current construction. Define
𝒞_a^i = Θ_a^i − (q/M) g_ab K_i^b
Structural Dirac locking requires 𝒞 = 0 and D𝒞[𝒪] = 0 for every admissible symmetry-preserving local deformation 𝒪.
Two Levels
| Level | Question |
|---|---|
| Finite derivative order | Choose a basis of independent gauge-invariant local operators modulo IBP, EOM, and field redefinitions. Compute the tangent vectors δ_A𝒞. If they span a nonzero subspace, ordinary symmetry does not protect the locking. |
| All orders | Does the local response kernel identity hold in the local-functional quotient? |
The Local Response Identity
The all-orders question is whether
ℛ_Θ − (q/M) ℛ_g = E_A Y^A + ∂_μ X^μ + (gauge/Ward identities)
holds in the local-functional quotient. This is where a genuine protecting mechanism would have to live.
A BPS equation, special moduli-space geometry, SUSY algebra, anomaly/WZ structure, or hidden symmetry is relevant only if it can be traced all the way to this response identity. Merely constraining M, quantizing q, producing spin 1/2, or giving a beautiful moduli-space metric is insufficient.
Closing State
The topological-current branch is closed. The metric-independent-current non-protection lemma is proved under the stated assumptions. The profile-preserving operator is explicit, local, symmetry-preserving, nonredundant, and has a strictly positive rotor matrix element. It changes the rotational kinetic metric while leaving the topological electromagnetic current unchanged.
The only surviving possibility for structural g = 2 in a purely bosonic theory is that the electromagnetic current and the moduli-space metric descend from a common microscopic structure, so that any deformation changing the metric also changes the current in exactly the same way. SUSY is one known example, but whether a specific supersymmetric soliton enforces the electromagnetic relation is a separate theorem. Ordinary BPS saturation already failed this test.
Classify the local identities capable of enforcing Θ_EM^i = (q/M) K_i^♭ under all allowed deformations.
What Remains Open
- The local response identity. The condition ℛ_Θ = (q/M) ℛ_g modulo EOM, total derivatives, and gauge identities has not been classified.
- The charged case. If U is charged under the electromagnetic U(1), the deformation may acquire explicit A_μ dependence. The non-protection lemma does not directly apply.
- SUSY as a solution. Whether a specific supersymmetric soliton satisfies the electromagnetic relation is not established. A central charge or BPS mass relation does not automatically prove the magnetic-response identity.
- Purely bosonic common structures. Whether any purely bosonic local structure can enforce the locking condition for all admissible deformations is open.
- The finite-order rank problem. At each derivative order, the tangent vectors δ_A𝒞 have not been computed for a general basis of operators.
The Honest Summary
The derivation produced one clean negative result and one sharp open problem. The negative result: a metric-independent topological electromagnetic current cannot, by topology alone, protect current–metric locking. The proof is constructive and survives the on-shell redundancy test. The open problem: classify the local identities capable of enforcing the locking condition, or prove that no purely bosonic structure of this type exists for a charged π₃ soliton.
The problem is no longer “find a clever soliton profile that gives g = 2.” It is: does there exist a microscopic identity whose local response content forces the electromagnetic magnetic-response functional and the rotational kinetic functional to be the same functional up to q/M?
Current–Metric Locking: The Topological-Current Route and the Charged-Case Boundary
A record of the derivation from structural g = 2 to the metric-independent topological-current non-protection lemma, and the precise boundary where the charged case remains open.
How to Read This Document
This is a record of a sustained derivation. It begins from the structural condition Mκ = Λ implied by g = 2 and follows the topology route as far as it goes. The neutral case is closed. The charged case is open, with a precise calculation pipeline. Every claim is labeled: proved, derived, conditional, ruled out, or open.
| Label | Meaning |
|---|---|
| Proved | Fully established by an explicit construction or a closed argument. |
| Derived | Follows from a calculation under stated assumptions. |
| Conditional | Holds only under assumptions not yet verified in general. |
| Ruled out | Contradicted by an explicit counterexample or a no-go argument. |
| Open | No calculation has settled it. |
| Corrected | An earlier claim in the derivation that was found to be wrong. |
Part I — The Sharpened Condition
From Mκ = Λ to Current–Metric Locking
The starting point is structural g = 2 for a charged rotating soliton. In collective-coordinate language, the magnetic moment κ and the moment of inertia Λ satisfy
M κ = Λ
The structural g = 2 condition.
This is equivalent to a mixed-response statement. Writing the energy as
E(B, Ω) = M + ½ Λ Ω² − q κ Ω·B + ⋯
the condition becomes
∂²E/∂Ω_i∂B_j |₀ = −(q/M) ∂²E/∂Ω_i∂Ω_j |₀
The sharpening is to ask what this requires of the moduli-space geometry. Rotation acts through rotational Killing vectors K_i^a. Electromagnetism acts through a U(1) connection whose magnetic response one-form is Θ_EM^i. The moment of inertia is Λ_ij = g_ab K_i^a K_j^b.
Θ_EM^i = (q/M) K_i^♭
This is much stronger than Mκ = Λ alone. It identifies a specific one-form on moduli space and demands that it be fixed by the rotational Killing vector. Nothing about topology, Bogomolny saturation, or Kähler geometry alone forces this identification.
Part II — The Neutral Topological-Current Route
The Metric-Independent Topological Current
The most natural candidate for a bosonic mechanism is a soliton whose electromagnetic current is a conserved topological current:
J_EM^μ = q_t B^μ, ∂_μ B^μ = 0
B^μ is the degree current of the SU(2) hedgehog.
If this is the whole story, then Θ_EM is determined entirely by B^μ, independently of the kinetic sector. The question is whether topology can protect the locking condition.
The Off-Shell Test
For the SU(2) hedgehog with unit winding, the topological density B⁰(r) satisfies
4π ∫₀^∞ r² B⁰(r) dr = 1
Topology fixes the normalization.
But the magnetic first moment involves an extra factor of r²:
μ_top = (q_t/3) ⟨r²⟩_B Ω
⟨r²⟩_B = ∫ r² B⁰(r) d³x
The normalization integral ∫ B⁰ d³x is topological. The first moment ∫ r² B⁰ d³x is not. It depends on the profile of B⁰(r), and therefore on the soliton shape.
Part III — The Measure Mismatch in BPS Skyrme
BPS Skyrme
The BPS Skyrme model is the most favorable bosonic soliton to test. Its Lagrangian is
ℒ_BPS = −λ²π⁴ B_μ B^μ − μ² V(U)
Squared baryon current plus a potential.
On a BPS solution the two terms are pointwise equal, so the static mass is
M = 2 λ² π⁴ ∫ ρ_B² d³x
The rotational inertia is
Λ = (4/3) λ² π⁴ ∫ r² ρ_B² d³x
The topological magnetic moment is
𝒦 = (q_t/3) ∫ r² ρ_B d³x
The Missing-Half Condition
The proposed identity for the topological contribution is 𝒦 = (q/2)(Λ/M). Substituting the BPS expressions gives
q_t ⟨r²⟩_{ρ_B} = q ⟨r²⟩_{ρ_B²}
Two different moments of the profile.
The left side is the mean-square radius weighted by baryon density. The right side is the mean-square radius weighted by squared baryon density. These are different functionals of the profile.
Bogomolny saturation of the BPS Skyrme model does not, by itself, enforce the topological missing-half condition. The potential remains a deformation direction inside the BPS class, and it changes the two moments differently.
Part IV — Failed Deformation Candidates
The Strategy
We need a profile-preserving deformation: a local, Lorentz-invariant, symmetry-preserving operator that
𝒪_*[φ₀] = 0, δ_static 𝒪_*[φ₀] = 0, δ²_Ω 𝒪_* ≠ 0
Such an operator leaves the static soliton and its mass unchanged, while changing the rotational kinetic metric. If it does not couple to A_μ, it also leaves the topological current unchanged.
Failed Candidates
| Candidate | Reason it fails |
|---|---|
| F(X) with X_{μν} = −½ Tr(L_μ L_ν) | No smooth algebraic scalar can satisfy F[U₀] = 0 and δ_rot F ≠ 0. |
| W = ε^{μνρσ} Tr(L_μ L_ν L_ρ L_σ) | Vanishes identically for SU(2). |
| (B^μ ∂_μ B²)² | On the spherical rotor, B^i ∂_i B² = 0. |
| B^μ B^ν Tr(∂_μ L_ν) | Identically zero: Tr(L_ν) = 0. |
| (Tr(L_μ L_ν) ∂^μ B^ν)² | Vanishes at O(Ω²) on the hedgehog by symmetry. |
Part V — The Profile-Preserving Deformation
The Surviving Operator
The obstruction is broken by using the derivative of the topological current:
𝒪_B = B^μ B^ν Tr(∂_μ L_α ∂_ν L^α)
L_α = U^{-1} ∂_α U.
This operator is local, Lorentz invariant, and symmetry preserving. It does not couple to A_μ.
Properties
The Rotor Matrix Element
Under a rigid rotation, the convective derivative 𝒟 = ∂_t + v·∇ rotates the spatial covector index of L_i:
𝒟 L_i = −(∂_i v^j) L_j = −ω_i^j L_j
After angular integration,
∫ d³x 𝒪_B^(2) = (16π/3) Ω² ∫₀^∞ dr r² ρ(r)² (f’² + 2 sin²f / r²)
The quadratic rotor matrix element is strictly positive for a nontrivial B = 1 hedgehog.
Part VI — The Non-Redundancy Test
The Redundancy Question
An operator can fail to change the physics if it is a total derivative, proportional to the equations of motion, or removable by a field redefinition. The question is whether
𝒪_B = E_A Y^A + ∂_μ V^μ
The On-Shell Test
Evaluate on the true adiabatic rotating solution φ_Ω = φ₀ + Ω Z_rot + Ω² η₂ + ⋯. Because 𝒪_B[φ₀] = 0 and D𝒪_B[φ₀] = 0, the quadratic matrix element is determined entirely by the rotational zero mode. The centrifugal correction η₂ does not contribute.
Suppose for contradiction that 𝒪_B = E_A Y^A + ∂_μ V^μ. On-shell, E_A = 0, so 𝒪_B = ∂_μ V^μ. Integrating over a closed rotational period T:
∫₀^T dt ∫ d³x ∂_μ V^μ = [∫ d³x V⁰]₀^T + ∫₀^T dt ∮_∞ dS_i V^i
The spatial boundary term vanishes by localization. The temporal term vanishes for single-valued local V⁰ over a closed orbit. Therefore redundancy would imply ∫₀^T dt ∫ d³x 𝒪_B = 0. But the explicit matrix element is TC Ω² + O(Ω³), nonzero.
𝒪_B ∉ ⟨E_A⟩ + dΩ³_loc
Part VII — The Neutral Result
The Lemma
For an SU(2) hedgehog whose electromagnetic coupling is supplied by a metric-independent topological current B^μ, current–metric locking cannot be protected solely by topology against arbitrary local Lorentz- and symmetry-preserving EFT deformations.
The proof is constructive. The operator 𝒪_B = B^μ B^ν Tr(∂_μ L_α ∂_ν L^α) is local, symmetry-preserving, vanishes on every static configuration, has vanishing first static variation, has a strictly positive quadratic rotor matrix element, and is nonredundant by the closed-orbit on-shell argument.
The Stated Assumptions
| Assumption | Role |
|---|---|
| U is neutral under the electromagnetic U(1) | Ensures the deformation does not induce an explicit A_μ dependence. |
| J_EM^μ = q_t B^μ | Defines the metric-independent current. |
| Adiabatic on-shell expansion is valid | Justifies evaluating on the slowly rotating solution. |
| Standard locality and falloff | Ensures the boundary terms vanish. |
Part VIII — The Charged Case
The Setup
If U is charged under the electromagnetic U(1), then J_EM^μ is a Noether current, not a topological current. The neutral-case deformation 𝒪_B does not directly apply. The natural generalization is
𝒪_c = ℬ^μ ℬ^ν Tr(∇_μ L_α ∇_ν L^α)
ℬ^μ is the gauge-invariant baryon current, L_μ = U^† D_μ U.
where the gauge-invariant baryon current must be derived from a fixed gauged action, not selected independently.
The Calculation in Hessian Form
Define two tangent directions in field space:
Z_Ω = ∂(U,A)/∂Ω |₀, Z_B = ∂(U,A)/∂B_ext |₀
The quantities we need are components of the second variation:
δΛ = D²S_c[Z_Ω, Z_Ω], e δκ = D²S_c[Z_Ω, Z_B]
Isotropy forces
D²S_c[Z_{Ω_i}, Z_{Ω_j}] = δ_ij ∫ dr W_Λ
D²S_c[Z_{Ω_i}, Z_{B_j}] = δ_ij ∫ dr W_κ
The Corrected Power Counting
For 𝒪_c = ℬ^μ ℬ^ν X_{μν} with X_{μν} = Tr(∇_μ L_α ∇_ν L^α), the background has ℬ^μ = (ρ, 0) and X₀₀ = 0. Therefore the mixed variation is
δ_B δ_Ω 𝒪_c = δ_B δ_Ω(ℬ^μ ℬ^ν X_{μν})
Because X₀₀^(0) = 0 and δ_Ω X₀₀ = 0, a large class of terms involving δ_B ℬ⁰ dies automatically. The potentially surviving pieces have the schematic form
2ρ (δ_Ω ℬ^i)(δ_B X_{0i}) + 2ρ (δ_B ℬ^i)(δ_Ω X_{0i}) + 2ρ δ_B δ_Ω X₀₀
plus any genuine mixed variation 2ρ (δ_B δ_Ω ℬ^i) X^(0)_{0i}, which itself vanishes if X^(0)_{0i} = 0.
Terms containing two rotational ∂₀L’s cannot contribute to the mixed Hessian at B = Ω = 0. The corrected counting is much smaller than the earlier expansion suggested.
The Intermediate Algebraic Test
Before deriving the full radial kernel, perform the intermediate test:
D²S_c[Z_Ω, Z_B] ≟ 0
using only covariance, hedgehog symmetry, and the background identities. If it vanishes identically, Gate 1 collapses to ΔW = −λ W_Λ, and the charged counterexample becomes dramatically simpler. If it does not vanish, only then derive the complete W_κ[f].
Part IX — The Proof Pipeline
The Remaining Gates
The IBP/EOM Test
Define ΔW[f] = W_κ[f] − λ W_Λ[f]. First test whether ΔW is a pure total derivative by taking its one-dimensional Euler operator:
ℰ_f(ΔW) = ∂ΔW/∂f − D_r(∂ΔW/∂f’) + D_r²(∂ΔW/∂f”) − ⋯
Every total derivative satisfies ℰ_f(D_r F) = 0. So if ℰ_f(ΔW) ≠ 0, pure IBP equivalence is excluded. Then test the stronger quotient ΔW ∼ 0 (mod E_f), which becomes a differential-algebra problem in the jet variables (r, f, f’, f”, f”’, …).
The Current Status
| Claim | Status |
|---|---|
| Neutral topological-current non-protection lemma | Proved |
| Gauged baryon current must be derived from fixed action | Corrected |
| W_Λ known in neutral limit | Derived |
| W_κ must be explicitly derived | Open |
| Mixed Hessian may vanish identically by symmetry | To be tested |
| IBP test via Euler operator | Defined |
| EOM test via local jet-space identity | Defined |
| Gauged nonredundancy via full coupled closed-orbit solution | Open |
| Ordinary gauge-invariance protection | Open |
Closing State
The neutral topological-current branch is closed. The metric-independent-current non-protection lemma is proved under the stated assumptions. The profile-preserving operator is explicit, local, symmetry-preserving, nonredundant, and has a strictly positive rotor matrix element.
The charged case is open, but the calculation is now sharply defined. The next step is not a vague search for a bosonic mechanism. It is a specific algebraic test: determine whether the mixed Hessian D²S_c[Z_Ω, Z_B] vanishes identically for the properly gauged operator. If it does, the charged counterexample is immediate. If it does not, derive W_κ[f] and test the local jet-space identity modulo IBP and EOM.
Determine whether D²S_c[Z_Ω, Z_B] vanishes identically by symmetry and covariance. If yes, the charged non-protection result follows. If no, compute W_κ[f] for a properly conserved gauged baryon current and test W_κ − λW_Λ modulo IBP/EOM.
What Remains Open
- The gauge-invariant baryon current. Must be derived from a fixed gauged action, not selected independently.
- The mixed Hessian. D²S_c[Z_Ω, Z_B] has not been computed.
- The radial kernel W_κ[f]. Not yet derived.
- The IBP/EOM quotient. The local jet-space identity has not been tested.
- Gauged nonredundancy. Requires the full coupled closed-orbit solution including the self-field.
- Ordinary gauge protection. Whether gauge invariance alone can enforce current–metric locking is open.
- Exceptional structures. SUSY, hidden symmetries, and non-generic geometric constructions have not been classified.
The Honest Summary
The derivation produced one clean negative result and one sharply defined open problem. The negative result: a metric-independent topological electromagnetic current cannot, by topology alone, protect current–metric locking. The open problem: whether ordinary gauge invariance can protect it in the charged case, and if not, what exceptional structure could.
The problem is no longer “find a clever soliton profile that gives g = 2.” It is: does there exist a microscopic identity whose local response content forces the electromagnetic magnetic-response functional and the rotational kinetic functional to be the same functional up to q/M?
Current–Metric Locking: The Topological-Current Route and the Charged-Case Boundary
A record of the derivation from structural g = 2 to the metric-independent topological-current non-protection lemma, and the precise boundary where the charged case remains open. Three epistemic levels kept separate throughout.
How to Read This Document
This is a record of a sustained derivation. It begins from the structural condition Mκ = Λ implied by g = 2 and follows the topological-current route as far as it goes. The neutral case is closed. The charged case is open, with a precise calculation pipeline. Every claim is labeled: proved, derived, conditional, ruled out, or open.
| Label | Meaning |
|---|---|
| Proved | Fully established by an explicit construction or a closed argument. |
| Derived | Follows from a calculation under stated assumptions. |
| Conditional | Holds only under assumptions not yet verified in general. |
| Ruled out | Contradicted by an explicit counterexample or a no-go argument. |
| Open | No calculation has settled it. |
| Corrected | An earlier claim in the derivation that was found to be wrong. |
The Three Epistemic Levels
The main thing worth preserving from this derivation is that there are now three distinct epistemic levels, and they should not be collapsed later.
| Level | Content |
|---|---|
| Proved | Metric-independent topological-current protection fails under the stated neutral-case assumptions. |
| Open but reduced | Ordinary charged bosonic protection, beginning with the mixed Hessian D²S_c[Z_Ω, Z_B]. |
| Open generally | Existence of any purely bosonic exceptional structure that enforces structural g = 2. |
These three levels correspond to three different kinds of statement: a closed negative theorem, a reduced calculation with explicit pass/fail gates, and an open classification problem. The document keeps them separate throughout.
Part I — The Sharpened Condition
From Mκ = Λ to Current–Metric Locking
The starting point is structural g = 2 for a charged rotating soliton. In collective-coordinate language, the magnetic moment κ and the moment of inertia Λ satisfy
M κ = Λ
The structural g = 2 condition.
This is equivalent to a mixed-response statement. Writing the energy as
E(B, Ω) = M + ½ Λ Ω² − q κ Ω·B + ⋯
the condition becomes
∂²E/∂Ω_i∂B_j |₀ = −(q/M) ∂²E/∂Ω_i∂Ω_j |₀
The sharpening is to ask what this requires of the moduli-space geometry. Rotation acts through rotational Killing vectors K_i^a. Electromagnetism acts through a U(1) connection whose magnetic response one-form is Θ_EM^i. The moment of inertia is Λ_ij = g_ab K_i^a K_j^b.
Θ_EM^i = (q/M) K_i^♭
This is much stronger than Mκ = Λ alone. It identifies a specific one-form on moduli space and demands that it be fixed by the rotational Killing vector. Nothing about topology, Bogomolny saturation, or Kähler geometry alone forces this identification.
Part II — The Neutral Topological-Current Route
The Metric-Independent Topological Current
The most natural candidate for a bosonic mechanism is a soliton whose electromagnetic current is a conserved topological current:
J_EM^μ = q_t B^μ, ∂_μ B^μ = 0
B^μ is the degree current of the SU(2) hedgehog.
If this is the whole story, then Θ_EM is determined entirely by B^μ, independently of the kinetic sector. The question is whether topology can protect the locking condition.
The Off-Shell Test
For the SU(2) hedgehog with unit winding, the topological density B⁰(r) satisfies
4π ∫₀^∞ r² B⁰(r) dr = 1
Topology fixes the normalization.
But the magnetic first moment involves an extra factor of r²:
μ_top = (q_t/3) ⟨r²⟩_B Ω
⟨r²⟩_B = ∫ r² B⁰(r) d³x
The normalization integral ∫ B⁰ d³x is topological. The first moment ∫ r² B⁰ d³x is not. It depends on the profile of B⁰(r), and therefore on the soliton shape.
Part III — The Measure Mismatch in BPS Skyrme
BPS Skyrme
The BPS Skyrme model is the most favorable bosonic soliton to test. Its Lagrangian is
ℒ_BPS = −λ²π⁴ B_μ B^μ − μ² V(U)
Squared baryon current plus a potential.
On a BPS solution the two terms are pointwise equal, so the static mass is
M = 2 λ² π⁴ ∫ ρ_B² d³x
The rotational inertia is
Λ = (4/3) λ² π⁴ ∫ r² ρ_B² d³x
The topological magnetic moment is
𝒦 = (q_t/3) ∫ r² ρ_B d³x
The Missing-Half Condition
The proposed identity for the topological contribution is 𝒦 = (q/2)(Λ/M). Substituting the BPS expressions gives
q_t ⟨r²⟩_{ρ_B} = q ⟨r²⟩_{ρ_B²}
Two different moments of the profile.
The left side is the mean-square radius weighted by baryon density. The right side is the mean-square radius weighted by squared baryon density. These are different functionals of the profile.
Bogomolny saturation of the BPS Skyrme model does not, by itself, enforce the topological missing-half condition. The potential remains a deformation direction inside the BPS class, and it changes the two moments differently.
Part IV — Failed Deformation Candidates
The Strategy
We need a profile-preserving deformation: a local, Lorentz-invariant, symmetry-preserving operator that
𝒪_*[φ₀] = 0, δ_static 𝒪_*[φ₀] = 0, δ²_Ω 𝒪_* ≠ 0
Such an operator leaves the static soliton and its mass unchanged, while changing the rotational kinetic metric. If it does not couple to A_μ, it also leaves the topological current unchanged.
Failed Candidates
| Candidate | Reason it fails |
|---|---|
| F(X) with X_{μν} = −½ Tr(L_μ L_ν) | No smooth algebraic scalar can satisfy F[U₀] = 0 and δ_rot F ≠ 0. |
| W = ε^{μνρσ} Tr(L_μ L_ν L_ρ L_σ) | Vanishes identically for SU(2): four one-forms in a three-dimensional Lie algebra. |
| (B^μ ∂_μ B²)² | On the spherical rotor, B^i ∂_i B² = 0 because the rotation is tangential to level surfaces of B². |
| B^μ B^ν Tr(∂_μ L_ν) | Identically zero: Tr(L_ν) = 0. |
| (Tr(L_μ L_ν) ∂^μ B^ν)² | Vanishes at O(Ω²) on the hedgehog by symmetry of X_ij and antisymmetry of ∂_i v_j. |
All these failures share a common geometric origin. For a spherical hedgehog, the rotation velocity v = Ω × x is tangential, and every invariant radial vector is proportional to n. The contraction v·n vanishes. Meanwhile the only invariant rank-two spatial tensor is symmetric, so it cannot contract with the antisymmetric rotation gradient.
Part V — The Profile-Preserving Deformation
The Surviving Operator
The obstruction is broken by using the derivative of the topological current:
𝒪_B = B^μ B^ν Tr(∂_μ L_α ∂_ν L^α)
L_α = U^{-1} ∂_α U.
This operator is local, Lorentz invariant, and symmetry preserving. It does not couple to A_μ.
Properties
The Rotor Matrix Element
Under a rigid rotation, the convective derivative 𝒟 = ∂_t + v·∇ rotates the spatial covector index of L_i:
𝒟 L_i = −(∂_i v^j) L_j = −ω_i^j L_j
After angular integration,
∫ d³x 𝒪_B^(2) = (16π/3) Ω² ∫₀^∞ dr r² ρ(r)² (f’² + 2 sin²f / r²)
The quadratic rotor matrix element is strictly positive for a nontrivial B = 1 hedgehog.
No Electromagnetic Response
Because 𝒪_B does not couple to A_μ, and because the topological current J_EM^μ = q_t B^μ is unchanged at linear order, the electromagnetic magnetic-response one-form Θ_EM is unchanged:
δ Θ_EM = 0, δ K^♭ ≠ 0
Part VI — The Non-Redundancy Test
The Redundancy Question
An operator can fail to change the physics if it is a total derivative, proportional to the equations of motion, or removable by a field redefinition. The question is whether
𝒪_B = E_A Y^A + ∂_μ V^μ
The On-Shell Test
Evaluate on the true adiabatic rotating solution φ_Ω = φ₀ + Ω Z_rot + Ω² η₂ + ⋯. Because 𝒪_B[φ₀] = 0 and D𝒪_B[φ₀] = 0, the quadratic matrix element is determined entirely by the rotational zero mode. The centrifugal correction η₂ does not contribute.
Suppose for contradiction that 𝒪_B = E_A Y^A + ∂_μ V^μ. On-shell, E_A = 0, so 𝒪_B = ∂_μ V^μ. Integrating over a closed rotational period T:
∫₀^T dt ∫ d³x ∂_μ V^μ = [∫ d³x V⁰]₀^T + ∫₀^T dt ∮_∞ dS_i V^i
The spatial boundary term vanishes by localization. The temporal term vanishes for single-valued local V⁰ over a closed orbit. Therefore redundancy would imply ∫₀^T dt ∫ d³x 𝒪_B = 0. But the explicit matrix element is TC Ω² + O(Ω³), nonzero.
𝒪_B ∉ ⟨E_A⟩ + dΩ³_loc
Part VII — The Neutral Result
The Lemma
For an SU(2) hedgehog whose electromagnetic coupling is supplied by a metric-independent topological current B^μ, current–metric locking cannot be protected solely by topology against arbitrary local Lorentz- and symmetry-preserving EFT deformations.
The proof is constructive. The operator 𝒪_B = B^μ B^ν Tr(∂_μ L_α ∂_ν L^α) is local, symmetry-preserving, vanishes on every static configuration, has vanishing first static variation, has a strictly positive quadratic rotor matrix element, and is nonredundant by the closed-orbit on-shell argument.
The Stated Assumptions
| Assumption | Role |
|---|---|
| U is neutral under the electromagnetic U(1) | Ensures the deformation does not induce an explicit A_μ dependence. |
| J_EM^μ = q_t B^μ | Defines the metric-independent current. |
| Adiabatic on-shell expansion is valid | Justifies evaluating on the slowly rotating solution. |
| Standard locality and falloff | Ensures the boundary terms vanish. |
Part VIII — The Charged Case
The Setup
If U is charged under the electromagnetic U(1), then J_EM^μ is a Noether current, not a topological current. The neutral-case deformation 𝒪_B does not directly apply. The natural generalization is
𝒪_c = ℬ^μ ℬ^ν Tr(∇_μ L_α ∇_ν L^α)
ℬ^μ is the gauge-invariant baryon current, L_μ = U^† D_μ U.
where the gauge-invariant baryon current must be derived from a fixed gauged action, not selected independently.
The Calculation in Hessian Form
Define two tangent directions in field space:
Z_Ω = ∂(U,A)/∂Ω |₀, Z_B = ∂(U,A)/∂B_ext |₀
The quantities we need are components of the second variation:
δΛ = D²S_c[Z_Ω, Z_Ω], e δκ = D²S_c[Z_Ω, Z_B]
Isotropy forces
D²S_c[Z_{Ω_i}, Z_{Ω_j}] = δ_ij ∫ dr W_Λ
D²S_c[Z_{Ω_i}, Z_{B_j}] = δ_ij ∫ dr W_κ
The Corrected Power Counting
For 𝒪_c = ℬ^μ ℬ^ν X_{μν} with X_{μν} = Tr(∇_μ L_α ∇_ν L^α), the background has ℬ^μ = (ρ, 0) and X₀₀ = 0. Therefore the mixed variation is
δ_B δ_Ω 𝒪_c = δ_B δ_Ω(ℬ^μ ℬ^ν X_{μν})
Because X₀₀^(0) = 0 and δ_Ω X₀₀ = 0, a large class of terms involving δ_B ℬ⁰ dies automatically. The potentially surviving pieces have the schematic form
2ρ (δ_Ω ℬ^i)(δ_B X_{0i}) + 2ρ (δ_B ℬ^i)(δ_Ω X_{0i}) + 2ρ δ_B δ_Ω X₀₀
plus any genuine mixed variation 2ρ (δ_B δ_Ω ℬ^i) X^(0)_{0i}, which itself vanishes if X^(0)_{0i} = 0.
Terms containing two rotational ∂₀L’s cannot contribute to the mixed Hessian at B = Ω = 0. The corrected counting is much smaller than the earlier expansion suggested.
The Intermediate Algebraic Test
Before deriving the full radial kernel, perform the intermediate test:
D²S_c[Z_Ω, Z_B] ≟ 0
using only covariance, hedgehog symmetry, and the background identities. This is the first gate of the charged case.
Part IX — The Proof Pipeline
The Remaining Fork
The mixed Hessian is the first gate. The exact remaining fork is
δκ = 0, δΛ ≠ 0
for the candidate at the response level, which closes Gate 1 very strongly. Gate 2 — the full gauged nonredundancy proof — is still required to promote the response mismatch into a genuine independent EFT deformation rather than an EOM/IBP artifact.The Two Gates
The IBP/EOM Test
Define ΔW[f] = W_κ[f] − λ W_Λ[f]. First test whether ΔW is a pure total derivative by taking its one-dimensional Euler operator:
ℰ_f(ΔW) = ∂ΔW/∂f − D_r(∂ΔW/∂f’) + D_r²(∂ΔW/∂f”) − ⋯
Every total derivative satisfies ℰ_f(D_r F) = 0. So if ℰ_f(ΔW) ≠ 0, pure IBP equivalence is excluded. Then test the stronger quotient ΔW ∼ 0 (mod E_f), which becomes a differential-algebra problem in the jet variables (r, f, f’, f”, f”’, …).
The Conditional Conclusion
If the appropriate mismatch and nonredundancy gates both pass, the result is
ordinary U(1) gauge invariance alone does not protect g = 2
That still leaves theories with additional exact structure untouched: supersymmetry, hidden symmetries, constrained operator algebras, non-generic geometric constructions.
The Current Status
| Claim | Status |
|---|---|
| Neutral topological-current non-protection lemma | Proved |
| Gauged baryon current must be derived from fixed action | Corrected |
| W_Λ known in neutral limit | Derived |
| W_κ must be explicitly derived | Open |
| Mixed Hessian may vanish identically by symmetry | To be tested |
| IBP test via Euler operator | Defined |
| EOM test via local jet-space identity | Defined |
| Gauged nonredundancy via full coupled closed-orbit solution | Open |
| Ordinary gauge-invariance protection | Open |
| Purely bosonic exceptional structures | Open generally |
Closing State
The neutral topological-current branch is closed. The metric-independent-current non-protection lemma is proved under the stated assumptions. The profile-preserving operator is explicit, local, symmetry-preserving, nonredundant, and has a strictly positive rotor matrix element.
The charged case is open, but the calculation is now sharply defined. The next step is not a vague search for a bosonic mechanism. It is a specific algebraic test: determine whether the mixed Hessian D²S_c[Z_Ω, Z_B] vanishes identically for the properly gauged operator.
Determine whether D²S_c[Z_Ω, Z_B] vanishes identically by symmetry and covariance. If yes, Gate 1 is closed and Gate 2 — gauged nonredundancy — becomes the remaining step. If no, compute W_κ[f] for a properly conserved gauged baryon current and test W_κ − λW_Λ modulo IBP/EOM.
What Remains Open
- The gauge-invariant baryon current. Must be derived from a fixed gauged action, not selected independently.
- The mixed Hessian. D²S_c[Z_Ω, Z_B] has not been computed.
- The radial kernel W_κ[f]. Not yet derived.
- The IBP/EOM quotient. The local jet-space identity has not been tested.
- Gauged nonredundancy. Requires the full coupled closed-orbit solution including the self-field.
- Ordinary gauge protection. Whether gauge invariance alone can enforce current–metric locking is open.
- Exceptional structures. SUSY, hidden symmetries, and non-generic geometric constructions have not been classified.
The Honest Summary
The derivation produced one clean negative result and one sharply defined open problem. The negative result: a metric-independent topological electromagnetic current cannot, by topology alone, protect current–metric locking. The open problem: whether ordinary gauge invariance can protect it in the charged case, and if not, what exceptional structure could.
The problem is no longer “find a clever soliton profile that gives g = 2.” It is: does there exist a microscopic identity whose local response content forces the electromagnetic magnetic-response functional and the rotational kinetic functional to be the same functional up to q/M?
The neutral theorem is finished. The general theorem is not. The charged problem has been reduced to a concrete calculation with explicit pass/fail gates. Nothing is being called finished that is not finished.
Current–Metric Locking: The Complete Derivation
From structural g = 2 to the non-protection of current–metric locking by ordinary U(1) gauge invariance. Neutral theorem closed. Charged case closed conditional on three technical hypotheses. Exceptional-structure protection remains open.
How to Read This Document
This is a record of a sustained derivation. It begins from the structural condition Mκ = Λ implied by g = 2 and follows the topology and gauge routes as far as they go. The neutral case is closed. The charged case is closed conditional on three technical hypotheses. The exceptional-structure question remains open. Every claim is labeled: proved, derived, conditional, ruled out, or open.
| Label | Meaning |
|---|---|
| Proved | Fully established by an explicit construction or a closed argument. |
| Derived | Follows from a calculation under stated assumptions. |
| Conditional | Holds only under assumptions not yet verified in general. |
| Ruled out | Contradicted by an explicit counterexample or a no-go argument. |
| Open | No calculation has settled it. |
| Corrected | An earlier claim in the derivation that was found to be wrong. |
The Three Epistemic Levels
The main thing worth preserving from this derivation is that there are now three distinct epistemic levels, and they should not be collapsed later.
| Level | Content |
|---|---|
| Proved | Metric-independent topological-current protection fails under the stated neutral-case assumptions. |
| Conditional | Ordinary charged bosonic protection fails, conditional on three technical hypotheses. |
| Open generally | Existence of any purely bosonic exceptional structure that enforces structural g = 2. |
Part I — The Sharpened Condition
From Mκ = Λ to Current–Metric Locking
The starting point is structural g = 2 for a charged rotating soliton. In collective-coordinate language, the magnetic moment κ and the moment of inertia Λ satisfy
M κ = Λ
The structural g = 2 condition.
This is equivalent to a mixed-response statement. Writing the energy as
E(B, Ω) = M + ½ Λ Ω² − q κ Ω·B + ⋯
the condition becomes
∂²E/∂Ω_i∂B_j |₀ = −(q/M) ∂²E/∂Ω_i∂Ω_j |₀
The sharpening is to ask what this requires of the moduli-space geometry. Rotation acts through rotational Killing vectors K_i^a. Electromagnetism acts through a U(1) connection whose magnetic response one-form is Θ_EM^i. The moment of inertia is Λ_ij = g_ab K_i^a K_j^b.
Θ_EM^i = (q/M) K_i^♭
This is much stronger than Mκ = Λ alone. It identifies a specific one-form on moduli space and demands that it be fixed by the rotational Killing vector. Nothing about topology, Bogomolny saturation, or Kähler geometry alone forces this identification.
Part II — The Neutral Topological-Current Route
The Metric-Independent Topological Current
The most natural candidate for a bosonic mechanism is a soliton whose electromagnetic current is a conserved topological current:
J_EM^μ = q_t B^μ, ∂_μ B^μ = 0
B^μ is the degree current of the SU(2) hedgehog.
If this is the whole story, then Θ_EM is determined entirely by B^μ, independently of the kinetic sector. The question is whether topology can protect the locking condition.
The Off-Shell Test
For the SU(2) hedgehog with unit winding, the topological density B⁰(r) satisfies
4π ∫₀^∞ r² B⁰(r) dr = 1
Topology fixes the normalization.
But the magnetic first moment involves an extra factor of r²:
μ_top = (q_t/3) ⟨r²⟩_B Ω
⟨r²⟩_B = ∫ r² B⁰(r) d³x
The normalization integral ∫ B⁰ d³x is topological. The first moment ∫ r² B⁰ d³x is not. It depends on the profile of B⁰(r), and therefore on the soliton shape.
Part III — The Measure Mismatch in BPS Skyrme
BPS Skyrme
The BPS Skyrme model is the most favorable bosonic soliton to test. Its Lagrangian is
ℒ_BPS = −λ²π⁴ B_μ B^μ − μ² V(U)
Squared baryon current plus a potential.
On a BPS solution the two terms are pointwise equal, so the static mass is
M = 2 λ² π⁴ ∫ ρ_B² d³x
The rotational inertia is
Λ = (4/3) λ² π⁴ ∫ r² ρ_B² d³x
The topological magnetic moment is
𝒦 = (q_t/3) ∫ r² ρ_B d³x
The Missing-Half Condition
The proposed identity for the topological contribution is 𝒦 = (q/2)(Λ/M). Substituting the BPS expressions gives
q_t ⟨r²⟩_{ρ_B} = q ⟨r²⟩_{ρ_B²}
Two different moments of the profile.
The left side is the mean-square radius weighted by baryon density. The right side is the mean-square radius weighted by squared baryon density. These are different functionals of the profile.
Bogomolny saturation of the BPS Skyrme model does not, by itself, enforce the topological missing-half condition. The potential remains a deformation direction inside the BPS class, and it changes the two moments differently.
Part IV — Failed Deformation Candidates
The Strategy
We need a profile-preserving deformation: a local, Lorentz-invariant, symmetry-preserving operator that
𝒪_*[φ₀] = 0, δ_static 𝒪_*[φ₀] = 0, δ²_Ω 𝒪_* ≠ 0
Such an operator leaves the static soliton and its mass unchanged, while changing the rotational kinetic metric. If it does not couple to A_μ, it also leaves the topological current unchanged.
Failed Candidates
| Candidate | Reason it fails |
|---|---|
| F(X) with X_{μν} = −½ Tr(L_μ L_ν) | No smooth algebraic scalar can satisfy F[U₀] = 0 and δ_rot F ≠ 0. |
| W = ε^{μνρσ} Tr(L_μ L_ν L_ρ L_σ) | Vanishes identically for SU(2): four one-forms in a three-dimensional Lie algebra. |
| (B^μ ∂_μ B²)² | On the spherical rotor, B^i ∂_i B² = 0 because the rotation is tangential to level surfaces of B². |
| B^μ B^ν Tr(∂_μ L_ν) | Identically zero: Tr(L_ν) = 0. |
| (Tr(L_μ L_ν) ∂^μ B^ν)² | Vanishes at O(Ω²) on the hedgehog by symmetry of X_ij and antisymmetry of ∂_i v_j. |
All these failures share a common geometric origin. For a spherical hedgehog, the rotation velocity v = Ω × x is tangential, and every invariant radial vector is proportional to n. The contraction v·n vanishes. Meanwhile the only invariant rank-two spatial tensor is symmetric, so it cannot contract with the antisymmetric rotation gradient.
Part V — The Profile-Preserving Deformation
The Surviving Operator
The obstruction is broken by using the derivative of the topological current:
𝒪_B = B^μ B^ν Tr(∂_μ L_α ∂_ν L^α)
L_α = U^{-1} ∂_α U.
This operator is local, Lorentz invariant, and symmetry preserving. It does not couple to A_μ.
Properties
The Rotor Matrix Element
Under a rigid rotation, the convective derivative 𝒟 = ∂_t + v·∇ rotates the spatial covector index of L_i:
𝒟 L_i = −(∂_i v^j) L_j = −ω_i^j L_j
After angular integration,
∫ d³x 𝒪_B^(2) = (16π/3) Ω² ∫₀^∞ dr r² ρ(r)² (f’² + 2 sin²f / r²)
The quadratic rotor matrix element is strictly positive for a nontrivial B = 1 hedgehog.
No Electromagnetic Response
Because 𝒪_B does not couple to A_μ, and because the topological current J_EM^μ = q_t B^μ is unchanged at linear order, the electromagnetic magnetic-response one-form Θ_EM is unchanged:
δ Θ_EM = 0, δ K^♭ ≠ 0
Part VI — The Non-Redundancy Test
The Redundancy Question
An operator can fail to change the physics if it is a total derivative, proportional to the equations of motion, or removable by a field redefinition. The question is whether
𝒪_B = E_A Y^A + ∂_μ V^μ
The On-Shell Test
Evaluate on the true adiabatic rotating solution φ_Ω = φ₀ + Ω Z_rot + Ω² η₂ + ⋯. Because 𝒪_B[φ₀] = 0 and D𝒪_B[φ₀] = 0, the quadratic matrix element is determined entirely by the rotational zero mode. The centrifugal correction η₂ does not contribute.
Suppose for contradiction that 𝒪_B = E_A Y^A + ∂_μ V^μ. On-shell, E_A = 0, so 𝒪_B = ∂_μ V^μ. Integrating over a closed rotational period T:
∫₀^T dt ∫ d³x ∂_μ V^μ = [∫ d³x V⁰]₀^T + ∫₀^T dt ∮_∞ dS_i V^i
The spatial boundary term vanishes by localization. The temporal term vanishes for single-valued local V⁰ over a closed orbit. Therefore redundancy would imply ∫₀^T dt ∫ d³x 𝒪_B = 0. But the explicit matrix element is TC Ω² + O(Ω³), nonzero.
𝒪_B ∉ ⟨E_A⟩ + dΩ³_loc
Part VII — The Neutral Result
The Lemma
For an SU(2) hedgehog whose electromagnetic coupling is supplied by a metric-independent topological current B^μ, current–metric locking cannot be protected solely by topology against arbitrary local Lorentz- and symmetry-preserving EFT deformations.
The proof is constructive. The operator 𝒪_B = B^μ B^ν Tr(∂_μ L_α ∂_ν L^α) is local, symmetry-preserving, vanishes on every static configuration, has vanishing first static variation, has a strictly positive quadratic rotor matrix element, and is nonredundant by the closed-orbit on-shell argument.
The Stated Assumptions
| Assumption | Role |
|---|---|
| U is neutral under the electromagnetic U(1) | Ensures the deformation does not induce an explicit A_μ dependence. |
| J_EM^μ = q_t B^μ | Defines the metric-independent current. |
| Adiabatic on-shell expansion is valid | Justifies evaluating on the slowly rotating solution. |
| Standard locality and falloff | Ensures the boundary terms vanish. |
Part VIII — The Charged Case
The Setup
If U is charged under the electromagnetic U(1), then J_EM^μ is a Noether current, not a topological current. The neutral-case deformation 𝒪_B does not directly apply. The natural generalization is
𝒪_c = ℬ^μ ℬ^ν Tr(∇_μ L_α ∇_ν L^α)
ℬ^μ is the gauge-invariant baryon current, L_μ = U^† D_μ U.
where the gauge-invariant baryon current must be derived from a fixed gauged action, not selected independently.
The Calculation in Hessian Form
Define two tangent directions in field space:
Z_Ω = ∂(U,A)/∂Ω |₀, Z_B = ∂(U,A)/∂B_ext |₀
The quantities we need are components of the second variation:
δΛ = D²S_c[Z_Ω, Z_Ω], e δκ = D²S_c[Z_Ω, Z_B]
Isotropy forces
D²S_c[Z_{Ω_i}, Z_{Ω_j}] = δ_ij ∫ dr W_Λ
D²S_c[Z_{Ω_i}, Z_{B_j}] = δ_ij ∫ dr W_κ
Part IX — Gate 1: The Mixed Hessian
The Corrected Expansion
The mixed Hessian is
D²S_c[Z_Ω, Z_B] = δ_Ω δ_B ∫ d⁴x 𝒪_c
On the static background at A = 0: ℬ^μ = (ρ, 0), L₀ = 0, L_i = l_i, X₀₀^(0) = 0, X₀ᵢ^(0) = 0, X_ij^(0) = Tr(l_i l_j).
The Two-Parameter Setup
Introduce two ordinary parameters s, t:
U_{s,t}(x) = A_s(t) U₀(x) A_s^†(t), A_μ = t a_μ^(B)
with A_s^† Ȧ_s = sω and a_i = ½(B_ext × x)_i. Then
D²S_c[Z_Ω, Z_B] = ∂²/∂s∂t ∫ d⁴x 𝒪_c(s,t) |_{s=t=0}
The Vanishing Terms
At s = 0, the configuration is static for all t. Therefore ∇₀ L_i = 0 for all t, and hence
δ_B ∇₀ L_i = ∂_t ∇₀ L_i |_{s=t=0} = 0
The standard gauge-invariant baryon current gives
δ_B ℬ^i = 0
on the static background, for both the Goldstone–Wilczek and Bardeen terms. The mixed Hessian becomes
D²S_c[Z_Ω, Z_B] = 2ρ² Tr(δ_Ω Y_{0α} δ_B Y_0^α) + 2ρ δ_Ω ℬ^i δ_B X_{i0} + 2ρ δ_B ℬ^i δ_Ω X_{i0}
All three terms vanish:
- The first because δ_B Y_0^α = 0.
- The second because δ_B X_{i0} = Tr(Y_{iα}^(0) δ_B Y_0^α) = 0.
- The third because δ_B ℬ^i = 0.
D²S_c[Z_Ω, Z_B] = 0, D²S_c[Z_Ω, Z_Ω] ≠ 0
The vanishing is kinematic. It does not depend on a radial cancellation. It follows from the structure of the mixed Hessian and the staticity of the magnetic tangent.
The earlier implication δ_B X₀₀ = 0 ⇒ δ_Ω δ_B X₀₀ = 0 was invalid. The correct chain uses δ_B Y_{0α} = 0, which follows from the staticity of the magnetic tangent at s = 0. The earlier treatment of δ_Ω ∇₀ L_i = 0 was also wrong: the rotational tangent is not a time-independent isorotation. The corrected argument gives the same result for the right reasons.
Part X — Gate 2: The Continuity Argument
The On-Shell Functional
Let e be the electromagnetic coupling and let
Φ_e(Ω) = (U_e(Ω), A_e(Ω))
be the coupled periodic rotating solution. Define
I(e,Ω) = ∫₀^{T(Ω)} dt ∫ d³x 𝒪_c[Φ_e(Ω)]
For small Ω, I(e,Ω) = T(Ω) C(e) Ω² + O(Ω⁴).
At e = 0, the neutral calculation gives
C(0) = (16π/3) ∫₀^∞ dr r² ρ² (f’² + 2 sin²f / r²) > 0
The Continuity Argument
Assume the coupled rotating branch exists and is continuous near e = 0. Then C(e) → C(0) > 0 as e → 0. Continuity gives ε > 0 such that C(e) ≠ 0 for 0 < |e| < ε.
Suppose 𝒪_c = E_U Y_U + E_A^μ Y_μ + ∂_μ V^μ. On the complete coupled solution, E_U = 0 and E_A^μ = 0. Over one closed collective orbit,
I(e,Ω) = [∫ d³x V⁰]₀^T + ∫₀^T dt ∮_∞ dS_i V^i
With localization, appropriate falloff, and single-valued local V^μ, both terms vanish. Hence redundancy requires I(e,Ω) = 0. But for sufficiently small nonzero e, I(e,Ω) = T C(e) Ω² + O(Ω⁴) ≠ 0. Contradiction.
𝒪_c ∉ ⟨E_U, E_A^μ⟩ + dΩ³_loc
for an open interval of genuinely nonzero gauge couplings.
The Three Technical Hypotheses
| Hypothesis | Status |
|---|---|
| The exact source-derived baryon current gives δ_B ℬ^i = 0 on the static background. | Plausible, standard terms vanish |
| The coupled rotating branch exists and is continuous near e = 0. | Standard perturbative assumption |
| The boundary terms in the closed-orbit argument vanish. | Standard falloff assumption |
Part XI — The Final Result
The Chain
The Narrow Statement
Ordinary U(1) gauge invariance alone does not protect current–metric locking.
The operator 𝒪_c = ℬ^μ ℬ^ν Tr(∇_μ L_α ∇_ν L^α) is a genuine independent EFT deformation that changes the moment of inertia without changing the magnetic moment. The result holds for an open interval of nonzero gauge couplings, which is sufficient to answer the symmetry-protection question.
What This Does Not Prove
It does not prove that structural bosonic g = 2 is impossible. An additional exact symmetry, constrained operator algebra, Ward identity, or geometric structure could still enforce current–metric locking. That exceptional-structure question remains open.
The Current Status
| Claim | Status |
|---|---|
| Neutral topological-current non-protection lemma | Proved |
| Gauged baryon current must be derived from fixed action | Corrected |
| W_Λ known in neutral limit | Derived |
| Mixed Hessian D²S_c[Z_Ω, Z_B] = 0 | Proved kinematically |
| Gate 1 | Closed |
| Gate 2 | Closed conditional on three hypotheses |
| Ordinary gauge protection | Disproved |
| Exceptional-structure protection | Open generally |
Closing State
The neutral topological-current branch is closed. The metric-independent-current non-protection lemma is proved under the stated assumptions. The charged case is closed conditional on three technical hypotheses. The result is that ordinary U(1) gauge invariance alone does not protect current–metric locking.
The only remaining possibility for structural g = 2 in a purely bosonic theory is an additional exact structure: supersymmetry, a hidden symmetry, a constrained operator algebra, a Ward identity, or a non-generic geometric construction. That exceptional-structure question is open.
Classify the local identities capable of enforcing Θ_EM^i = (q/M) K_i^♭ under all allowed deformations, or prove that no purely bosonic structure of this type exists for a charged π₃ soliton.
What Remains Open
- The exact source-derived baryon current. The check that δ_B ℬ^i = 0 for the specific gauged action should be completed.
- The continuity of the coupled rotating branch. Standard perturbative assumption, but not proved.
- The boundary terms. Falloff assumptions should be verified for the specific theory.
- Exceptional structures. SUSY, hidden symmetries, constrained operator algebras, and non-generic geometric constructions have not been classified.
- The local response identity. The condition ℛ_Θ = (q/M) ℛ_g modulo EOM, total derivatives, and gauge identities has not been classified.
The Honest Summary
The derivation produced two clean negative results and one sharply defined open problem. The negative results: a metric-independent topological electromagnetic current cannot, by topology alone, protect current–metric locking; and ordinary U(1) gauge invariance alone cannot protect it either. The open problem: whether any purely bosonic exceptional structure can.
The problem is no longer “find a clever soliton profile that gives g = 2.” It is: does there exist a microscopic identity whose local response content forces the electromagnetic magnetic-response functional and the rotational kinetic functional to be the same functional up to q/M?
The neutral theorem is finished. The charged theorem is finished conditional on three technical hypotheses. The general theorem is not. Nothing is being called finished that is not finished.
Current–Metric Locking: The Complete Derivation
From structural g = 2 to the non-protection of current–metric locking by ordinary U(1) gauge invariance. Neutral theorem proved. Charged case reduced to a finite-dimensional principal-symbol obstruction plus small-coupling persistence. Exceptional-structure protection remains open.
How to Read This Document
This is a record of a sustained derivation. It begins from the structural condition Mκ = Λ implied by g = 2 and follows the topology and gauge routes as far as they go. The neutral case is proved. The charged case is reduced to a principal-symbol obstruction plus a small-coupling persistence argument. The exceptional-structure question remains open.
| Label | Meaning |
|---|---|
| Proved | Fully established by an explicit construction or a closed argument. |
| Derived | Follows from a calculation under stated assumptions. |
| Conditional | Holds only under assumptions not yet verified in general. |
| Ruled out | Contradicted by an explicit counterexample or a no-go argument. |
| Open | No calculation has settled it. |
| Corrected | An earlier claim in the derivation that was found to be wrong. |
The Three Epistemic Levels
The main thing worth preserving from this derivation is that there are now three distinct epistemic levels, and they should not be collapsed later.
| Level | Content |
|---|---|
| Proved | Metric-independent topological-current protection fails under the stated neutral-case assumptions. |
| Reduced | Ordinary charged bosonic protection fails, reduced to a finite-dimensional principal-symbol obstruction plus small-coupling persistence. |
| Open generally | Existence of any purely bosonic exceptional structure that enforces structural g = 2. |
Part I — The Sharpened Condition
From Mκ = Λ to Current–Metric Locking
The starting point is structural g = 2 for a charged rotating soliton. In collective-coordinate language, the magnetic moment κ and the moment of inertia Λ satisfy
M κ = Λ
The structural g = 2 condition.
This is equivalent to a mixed-response statement. Writing the energy as
E(B, Ω) = M + ½ Λ Ω² − q κ Ω·B + ⋯
the condition becomes
∂²E/∂Ω_i∂B_j |₀ = −(q/M) ∂²E/∂Ω_i∂Ω_j |₀
The sharpening is to ask what this requires of the moduli-space geometry. Rotation acts through rotational Killing vectors K_i^a. Electromagnetism acts through a U(1) connection whose magnetic response one-form is Θ_EM^i. The moment of inertia is Λ_ij = g_ab K_i^a K_j^b.
Θ_EM^i = (q/M) K_i^♭
This is much stronger than Mκ = Λ alone. It identifies a specific one-form on moduli space and demands that it be fixed by the rotational Killing vector. Nothing about topology, Bogomolny saturation, or Kähler geometry alone forces this identification.
Part II — The Neutral Route and Its Closure
The Metric-Independent Topological Current
The most natural candidate for a bosonic mechanism is a soliton whose electromagnetic current is a conserved topological current:
J_EM^μ = q_t B^μ, ∂_μ B^μ = 0
B^μ is the degree current of the SU(2) hedgehog.
The Off-Shell Test
For the SU(2) hedgehog with unit winding, the topological density B⁰(r) satisfies
4π ∫₀^∞ r² B⁰(r) dr = 1
Topology fixes the normalization.
But the magnetic first moment involves an extra factor of r²:
μ_top = (q_t/3) ⟨r²⟩_B Ω
⟨r²⟩_B = ∫ r² B⁰(r) d³x
The normalization integral ∫ B⁰ d³x is topological. The first moment ∫ r² B⁰ d³x is not. It depends on the profile of B⁰(r), and therefore on the soliton shape.
The Measure Mismatch in BPS Skyrme
The BPS Skyrme model is the most favorable bosonic soliton to test. Its Lagrangian is
ℒ_BPS = −λ²π⁴ B_μ B^μ − μ² V(U)
On a BPS solution the two terms are pointwise equal, so the static mass is
M = 2 λ² π⁴ ∫ ρ_B² d³x
The rotational inertia is
Λ = (4/3) λ² π⁴ ∫ r² ρ_B² d³x
The topological magnetic moment is
𝒦 = (q_t/3) ∫ r² ρ_B d³x
The missing-half condition 𝒦 = (q/2)(Λ/M) becomes
q_t ⟨r²⟩_{ρ_B} = q ⟨r²⟩_{ρ_B²}
Two different moments of the profile.
Bogomolny saturation of the BPS Skyrme model does not, by itself, enforce the topological missing-half condition. The potential remains a deformation direction inside the BPS class, and it changes the two moments differently.
Failed Deformation Candidates
| Candidate | Reason it fails |
|---|---|
| F(X) with X_{μν} = −½ Tr(L_μ L_ν) | No smooth algebraic scalar can satisfy F[U₀] = 0 and δ_rot F ≠ 0. |
| W = ε^{μνρσ} Tr(L_μ L_ν L_ρ L_σ) | Vanishes identically for SU(2): four one-forms in a three-dimensional Lie algebra. |
| (B^μ ∂_μ B²)² | On the spherical rotor, B^i ∂_i B² = 0 because the rotation is tangential to level surfaces of B². |
| B^μ B^ν Tr(∂_μ L_ν) | Identically zero: Tr(L_ν) = 0. |
| (Tr(L_μ L_ν) ∂^μ B^ν)² | Vanishes at O(Ω²) on the hedgehog by symmetry of X_ij and antisymmetry of ∂_i v_j. |
The Profile-Preserving Deformation
The obstruction is broken by using the derivative of the topological current:
𝒪_B = B^μ B^ν Tr(∂_μ L_α ∂_ν L^α)
L_α = U^{-1} ∂_α U.
Under a rigid rotation, the convective derivative rotates the spatial covector index of L_i:
𝒟 L_i = −(∂_i v^j) L_j = −ω_i^j L_j
After angular integration,
∫ d³x 𝒪_B^(2) = (16π/3) Ω² ∫₀^∞ dr r² ρ(r)² (f’² + 2 sin²f / r²)
The Neutral Non-Redundancy Proof
Evaluate on the true adiabatic rotating solution φ_Ω = φ₀ + Ω Z_rot + Ω² η₂ + ⋯. Because 𝒪_B[φ₀] = 0 and D𝒪_B[φ₀] = 0, the quadratic matrix element is determined entirely by the rotational zero mode.
Suppose for contradiction that 𝒪_B = E_A Y^A + ∂_μ V^μ. On-shell, E_A = 0, so 𝒪_B = ∂_μ V^μ. Integrating over a closed rotational period T:
∫₀^T dt ∫ d³x ∂_μ V^μ = [∫ d³x V⁰]₀^T + ∫₀^T dt ∮_∞ dS_i V^i
The spatial boundary term vanishes by localization. The temporal term vanishes for single-valued local V⁰ over a closed orbit. Therefore redundancy would imply ∫₀^T dt ∫ d³x 𝒪_B = 0. But the explicit matrix element is TC Ω² + O(Ω³), nonzero.
For an SU(2) hedgehog whose electromagnetic coupling is supplied by a metric-independent topological current B^μ, current–metric locking cannot be protected solely by topology against arbitrary local Lorentz- and symmetry-preserving EFT deformations.
𝒪_B ∉ ⟨E_A⟩ + dΩ³_loc
Part III — The Charged Case
The Setup
If U is charged under the electromagnetic U(1), then J_EM^μ is a Noether current, not a topological current. The natural generalization is
𝒪_c = ℬ^μ ℬ^ν Tr(∇_μ L_α ∇_ν L^α)
ℬ^μ is the gauge-invariant baryon current, L_μ = U^† D_μ U.
where the gauge-invariant baryon current must be derived from a fixed gauged action.
The Calculation in Hessian Form
Define two tangent directions in field space:
Z_Ω = ∂(U,A)/∂Ω |₀, Z_B = ∂(U,A)/∂B_ext |₀
The quantities we need are components of the second variation:
δΛ = D²S_c[Z_Ω, Z_Ω], e δκ = D²S_c[Z_Ω, Z_B]
Isotropy forces
D²S_c[Z_{Ω_i}, Z_{Ω_j}] = δ_ij ∫ dr W_Λ
D²S_c[Z_{Ω_i}, Z_{B_j}] = δ_ij ∫ dr W_κ
Part IV — Gate 1: The Mixed Hessian
The Corrected Expansion
On the static background at A = 0: ℬ^μ = (ρ, 0), L₀ = 0, L_i = l_i, X₀₀^(0) = 0, X₀ᵢ^(0) = 0, X_ij^(0) = Tr(l_i l_j).
Introduce two ordinary parameters s, t:
U_{s,t}(x) = A_s(t) U₀(x) A_s^†(t), A_μ = t a_μ^(B)
with A_s^† Ȧ_s = sω and a_i = ½(B_ext × x)_i. Then
D²S_c[Z_Ω, Z_B] = ∂²/∂s∂t ∫ d⁴x 𝒪_c(s,t) |_{s=t=0}
At s = 0, the configuration is static for all t. Therefore ∇₀ L_i = 0 for all t, and hence δ_B ∇₀ L_i = 0. The standard gauge-invariant baryon current gives δ_B ℬ^i = 0 on the static background. The mixed Hessian becomes
D²S_c[Z_Ω, Z_B] = 2ρ² Tr(δ_Ω Y_{0α} δ_B Y_0^α) + 2ρ δ_Ω ℬ^i δ_B X_{i0} + 2ρ δ_B ℬ^i δ_Ω X_{i0}
All three terms vanish. The first because δ_B Y_0^α = 0. The second because δ_B X_{i0} = Tr(Y_{iα}^(0) δ_B Y_0^α) = 0. The third because δ_B ℬ^i = 0.
D²S_c[Z_Ω, Z_B] = 0, D²S_c[Z_Ω, Z_Ω] ≠ 0
The vanishing is kinematic. It follows from the structure of the mixed Hessian and the staticity of the magnetic tangent.
The earlier implication δ_B X₀₀ = 0 ⇒ δ_Ω δ_B X₀₀ = 0 was invalid. The correct chain uses δ_B Y_{0α} = 0, which follows from the staticity of the magnetic tangent at s = 0. The earlier treatment of δ_Ω ∇₀ L_i = 0 was also wrong: the rotational tangent is not a time-independent isorotation. The corrected argument gives the same result for the right reasons.
Part V — The Source-Derived Current
The Fixed Action
Fix the action:
S = S_Sk[U,A] + S_Maxwell[A] + S_gWZ[U,A,ℬ_μ]
where ℬ_μ is a background source for baryon number. The gauge-invariant baryon current is defined by
ℬ^μ_GI = δS_gWZ/δℬ_μ |_{ℬ=0}
The standard descent gives
ℬ^μ_GI = B^μ + (e/8π²) ε^{μνρσ} ∂_ν[A_ρ Tr(QL_σ)] + (1/16π²) ε^{μνρσ} A_ν F_{ρσ} Tr(Q²) + O(A²,∂A)
Variation on the Static Background
At A = 0, the background is static: L₀ = 0, and ∂₀ of any static quantity is zero.
Goldstone–Wilczek term
δ_B ℬ^i_GW = (e/8π²) ε^{iνkσ} ∂_ν Tr(QL_σ) |_{A=0}
For the epsilon tensor to be nonzero, i, k, σ, ν must be distinct. Since i, k, σ are spatial, ν = 0. Then ∂₀ of a static quantity vanishes.
δ_B ℬ^i_GW = 0
Bardeen term
δ_B ℬ^i_Bardeen = (1/16π²) ε^{iνρσ} [δA_ν F_{ρσ} + A_ν δF_{ρσ}] Tr(Q²) |_{A=0}
At A = 0, both A_ν = 0 and F_{ρσ} = 0, so both terms vanish.
δ_B ℬ^i = 0 for the GW+Bardeen current derived from the fixed gWZ action.
This is the current of a specific action, not an arbitrary ansatz. The index structure excludes local gauge-invariant improvements.
Part VI — Gate 2: The Principal-Symbol Test
Reduction to a Local Test
The closed-orbit argument does not carry over to the zero-frequency adiabatic setting, because the collective configuration is not an exact four-dimensional solution. The correct local test is the off-shell jet-space identity:
𝒪_c – E_A Y^A – ∂_μ V^μ ≡ 0
The best first attack is the principal time-derivative symbol.
The Quadratic Symbol of 𝒪_c
Write U = U₀e^ξ, so δL_μ = D_μξ. At principal order δL_μ ≈ ∂_μξ. On a static background, B^μ = (ρ, 0). For a plane-wave fluctuation ξ = v e^{-iωt+ikz},
δL_0 ≈ -iωv, δL_3 ≈ ikv
Therefore
P_c(ω,k) ∝ ρ² ω²(ω² − k²) 1
The quadratic principal symbol of 𝒪_c is not only p₀²|p|². The α = 0 term contributes a p₀⁴ piece. This was invisible in the rigid-rotor calculation because there L₀ = O(Ω) and its convective derivative is O(Ω²). For arbitrary high-frequency fluctuations it must be retained.
The Skyrme Characteristic Matrix at p ∥ n
At a point on the hedgehog, choose the spatial 3-axis along n. The background Maurer–Cartan forms have
X_T = sin²f / r², X_R = f’²
Let A be the sigma-model coefficient and C the Skyrme coefficient. For p ∥ n, the principal quadratic form diagonalizes by internal polarization.
H_R(ω,k) = [A + 2CX_T](ω² − k²)
Radial polarization. Characteristic: ω_R² = k².
H_T(ω,k) = [A + C(X_T+X_R)]ω² − [A+CX_T]k²
Transverse polarization. Characteristic: ω_T² = (A+CX_T)/(A+C(X_T+X_R)) k².
The sigma model alone is luminal: P_c ∝ (ω² − k²), characteristic ω² = k², both vanish simultaneously. The Skyrme term is what splits the transverse cone away from Minkowski while P_c retains the Minkowski factor. The obstruction comes from the Skyrme term.
Part VII — The Transverse Characteristic Obstruction
Evaluation on the Kernel
For the radial mode, ω_R² = k², so P_c(ω_R,k) = 0. No obstruction.
For a transverse characteristic mode,
ω_T² − k² = −CX_R / [A+C(X_T+X_R)] k²
Therefore
v_T† P_c v_T ∝ −ρ² CX_R[A+CX_T] / [A+C(X_T+X_R)]² k⁴|v_T|²
At a generic point of a nontrivial hedgehog, ρ ≠ 0 and X_R = f’² ≠ 0, and with A, C > 0,
v_T† P_c(ω_T,k) v_T ≠ 0
For the standard B = 1 hedgehog, f(r) = π + ar + O(r³), so f'(0) = a can be nonzero. Then X_R → a² and X_T → a², and the baryon density approaches a finite nonzero limit. The obstruction need not disappear at the center. What becomes isotropic there is X_R = X_T, not X_R = 0.
Part VIII — The Divergence Loophole Removed
The Problem with the Integrated Argument
If 𝒪_c = E_A Y^A + ∂_μ V^μ, then on an exact periodic on-shell solution the integrated 𝒪_c would vanish. But the zero-frequency collective configuration is not an exact four-dimensional solution. On it, E_A ≠ 0 at the relevant higher adiabatic order, so the EOM piece and the divergence piece are evaluated on two different configurations. They do not form a contradiction.
The Euler Operator Test
Apply the Euler–Lagrange operator to the proposed identity. Since the Euler operator annihilates local divergences identically,
E_A(∂_μ V^μ) ≡ 0
redundancy requires
E_A(𝒪_c) = E_A(E_B Y^B)
At quadratic order around the static background, if
S_c^(2) = ½ ∫ ξ† P_c(∂) ξ
then its Euler derivative is essentially the formally self-adjoint operator P_c. A divergence has disappeared automatically. For an infinitesimal field redefinition with linearization R, the quadratic EOM-exact contribution has Euler operator
P_red = H† R + R† H
Now the characteristic-kernel argument becomes legitimate without any V^μ. If Hv = 0, then because the Hessian principal symbol is self-adjoint, v†H† = 0. Hence
v† P_red v = 0
But the transverse Skyrme characteristic gives
v_T† P_c v_T ∝ −ρ² CX_R(A+CX_T) / [A+C(X_T+X_R)]² k⁴|v_T|² ≠ 0
𝒪_c ≠ E_A Y^A + ∂_μ V^μ
The total-divergence loophole is removed by the Euler operator without constructing V^μ. The matter-sector EOM/IBP redundancy is excluded at principal order.
Part IX — Small-Coupling Persistence
The Coupled Principal Matrix
Write the coupled U(1) + Skyrme principal matrix as
𝕙(e,p) = ( H_UU(p)+O(e) O(e) ; O(e) H_AA(p)+O(e) )
At e = 0, the matter and Maxwell blocks decouple. The matter block has the transverse characteristic mode with the nonzero Euler-symbol matrix element.
Perturbation Theory
At a generic point where ρX_R ≠ 0, choose a transverse characteristic root at e = 0. If that root remains regular, ordinary matrix perturbation theory gives
ω_T(e) = ω_T(0) + O(e)
and a continuously varying eigenvector v_T(e). Consequently,
v_T(e)† P_c(e) v_T(e) = v_T(0)† P_c(0) v_T(0) + O(e)
Since the zeroth-order number is nonzero,
v_T(e)† P_c(e) v_T(e) ≠ 0
for sufficiently small e.
Part X — The Final Status
The Chain
The Narrow Statement
Ordinary U(1) gauge invariance alone does not protect current–metric locking.
The operator 𝒪_c = ℬ^μ ℬ^ν Tr(∇_μ L_α ∇_ν L^α) is a genuine independent EFT deformation that changes the moment of inertia without changing the magnetic moment.
What This Does Not Prove
It does not prove that structural bosonic g = 2 is impossible. An additional exact symmetry, constrained operator algebra, Ward identity, or geometric structure could still enforce current–metric locking. That exceptional-structure question remains open.
The Status Table
| Claim | Status |
|---|---|
| Neutral topological-current non-protection lemma | Proved |
| Gate 1: mixed Hessian D²S_c[Z_Ω, Z_B] = 0 | Proved kinematically |
| Source-derived current δ_B ℬ^i = 0 | Proved for GW+Bardeen |
| Skyrme characteristic matrix at p ∥ n | Computed |
| Transverse characteristic obstruction | Nonzero |
| Total-divergence loophole | Removed by Euler operator |
| Matter EOM/IBP redundancy | Excluded at principal order |
| Small-e gauged persistence | Finite-dimensional perturbation step |
| Ordinary gauge protection | Disproved |
| Exceptional-structure protection | Open generally |
Closing State
The neutral topological-current branch is closed. The charged case is reduced to a finite-dimensional principal-symbol obstruction plus a small-coupling persistence argument. The result is that ordinary U(1) gauge invariance alone does not protect current–metric locking.
The mechanism is exactly the one identified in the principal-symbol calculation: the sigma model alone is luminal and makes P_c vanish on shell; the Skyrme term splits the transverse cone away from Minkowski while P_c retains the Minkowski factor. The obstruction comes from the Skyrme term.
Classify the local identities capable of enforcing Θ_EM^i = (q/M) K_i^♭ under all allowed deformations, or prove that no purely bosonic structure of this type exists for a charged π₃ soliton.
What Remains Open
- The local response identity. The condition ℛ_Θ = (q/M) ℛ_g modulo EOM, total derivatives, and gauge identities has not been classified.
- Small-e persistence. The perturbation theory argument is standard but should be completed explicitly.
- The global/static continuation. Separate from the local cohomological question, needed only if a full soliton theorem is required.
- Exceptional structures. SUSY, hidden symmetries, constrained operator algebras, and non-generic geometric constructions have not been classified.
- Purely bosonic common structures. Whether any purely bosonic local structure can enforce the locking condition for all admissible deformations is open.
The Honest Summary
The derivation produced two clean negative results and one sharply defined open problem. The negative results: a metric-independent topological electromagnetic current cannot, by topology alone, protect current–metric locking; and ordinary U(1) gauge invariance alone cannot protect it either. The open problem: whether any purely bosonic exceptional structure can.
The problem is no longer “find a clever soliton profile that gives g = 2.” It is: does there exist a microscopic identity whose local response content forces the electromagnetic magnetic-response functional and the rotational kinetic functional to be the same functional up to q/M?
The neutral theorem is finished. The charged theorem is reduced to a finite-dimensional principal-symbol obstruction plus a standard perturbation step. The general theorem is not. Nothing is being called finished that is not finished.
Current–Metric Locking: The Complete Derivation
From structural g = 2 to the principal-symbol cohomological obstruction for the specified gauged SU(2) Skyrme theory. Neutral lemma proved. Principal-symbol obstruction reproducible from the present record. Background algebra at the pole now includes the verified \(l_\theta\) value, the invariant \(-\tfrac12\mathrm{Tr}(l_\theta^2) = \sin^2 f\), and the single-chirality phase-lock structure \(e^{if}\tau_-\). Small-e charged theorem conditional on asserted continuation assumptions. Numerical window undetermined. All-e continuation, the general response identity, and exceptional structures are separate open problems.
How to Read This Document
This is a record of a sustained derivation. It begins from the structural condition Mκ = Λ implied by g = 2 and follows the topology and gauge routes to a sharp result. The neutral case is proved. The charged case has a principal-symbol cohomological obstruction that is reproducible from the present record; the small-e existence theorem is conditional on continuation assumptions that are asserted but not displayed. The numerical size of the window is undetermined. The broader questions — all-e continuation, the general response identity, and exceptional structures — are separate open problems.
Labels and Inspectability
Two label systems are used. The first records the logical status of a claim. The second records the evidentiary basis for it. Both matter, and they are not the same thing.
Logical status
| Label | Meaning |
|---|---|
| Proved | Fully established by an explicit construction or a closed argument. |
| Derived | Follows from a calculation under stated assumptions. |
| Conditional | Holds only under assumptions not yet verified in general. |
| Ruled out | Contradicted by an explicit counterexample or a no-go argument. |
| Open | No calculation has settled it. |
| Corrected | An earlier claim in the derivation that was found to be wrong. |
Evidentiary basis
| Category | Meaning |
|---|---|
| Reproducible-here | Steps displayed in this record, sufficient to reconstruct the claim. |
| Reproducible from available source | Derivation or executable output exists and can be inspected. |
| Asserted-not-inspectable | Transcript-reported, recalled, or summarized. Not a premise for further derivation. |
| Open | Neither a reproducible derivation nor inspectable output exists. |
Labels are sticky and per-result. A claim moves category only when the underlying derivation is recovered or the calculation is independently reproduced in this record. Reconstructing one result does not upgrade neighbouring claims.
Summary of Results
For an SU(2) hedgehog whose electromagnetic coupling is supplied by a metric-independent topological current \(B^\mu\), current–metric locking cannot be protected solely by topology against arbitrary local Lorentz- and symmetry-preserving EFT deformations.
\(\mathcal O_B \notin \langle E_A\rangle + d\Omega^3_{\rm loc}\)
Proved Reproducible-here
For the specified gauged SU(2) Skyrme theory, with the fixed gauge-invariant baryon-current prescription, the local deformation \(\mathcal O_c\) fails the principal-symbol Euler-operator identity. Consequently \(\mathcal O_c\) is not EOM-redundant at leading symbol order.
\(v_T^\dagger P_{c,\rm prin}(\omega_T,k)v_T \propto -\rho^2\frac{CX_R(A+CX_T)}{[A+C(X_T+X_R)]^2}k^4|v_T|^2 \neq 0\)
Derived Reproducible-here
Under the convention \(U_0 = \cos f + i(\tau\cdot n)\sin f\), at the north pole \(\theta = 0\), \(\varphi = 0\):
\(l_\theta|_{\rm pole} = i\left(\sin f\cos f\,\tau_1 + \sin^2 f\,\tau_2\right).\)
The \(\tau_1\) coefficient is \(\sin f\cos f = \tfrac12\sin 2f\), not \(\tfrac12\sin^2 f\). The invariant check \(-\tfrac12{\rm Tr}(l_\theta^2) = \sin^2 f\) is satisfied by the form above and fails for the \(\tfrac12\sin^2 f\) form. The result is independent of the left- or right-acting Maurer–Cartan convention for the \(\tau_1\) coefficient.
Derived Reproducible-here
At the pole, the Cartesian Maurer–Cartan forms are
\(l_x = \tfrac{i}{r}(\sin f\cos f\,\tau_1 + \sin^2 f\,\tau_2), \qquad l_y = \tfrac{i}{r}(-\sin^2 f\,\tau_1 + \sin f\cos f\,\tau_2).\)
The circular combination is single-chirality and carries phase \(e^{if}\):
\(l_x – i l_y = \tfrac{i\sin f}{r}e^{if}\tau_- = \tfrac{2i\sin f}{r}e^{if}T_-\).
The \(e^{if}\) phase and single chirality are reproducible here. Whether the transcript’s exact string \(2\sin f\,e^{if}\) referred to this coefficient after stripping the conventional \(i/r\) factor remains asserted-not-inspectable.
Derived Reproducible-here
For the specified gauged SU(2) Skyrme theory, with the fixed gauge-invariant baryon-current prescription, the principal-symbol obstruction of \(\mathcal O_c\) persists from \(e=0\) to all sufficiently small nonzero \(|e|\). The leading deterioration is \(O(e^2)\).
Conditional Asserted-not-inspectable on the coupled-branch continuation and Riesz-projector assumptions.
The e = 0 cohomological anchor is reproducible-here. The continuation portion — existence and smoothness of the coupled rotating branch in e, Fredholm invertibility of the linearized operator on weighted spaces after zero-mode projection — is asserted-not-inspectable. The theorem as a whole inherits the weaker label.
- The coupled-branch continuation and Riesz-projector assumptions have not been displayed. The small-e theorem is conditional on them.
- The numerical size of the small-coupling neighborhood \(\epsilon\) is undetermined.
- Whether any particular numerical or physical coupling lies inside the window is not established.
- The “twice the rate” precession claim for the transverse Maurer–Cartan form is not established by the \(e^{if}\) phase-lock result; it requires its own derivation.
- Whether any purely bosonic exceptional structure can enforce current–metric locking is open.
Part I — The Sharpened Condition
From Mκ = Λ to Current–Metric Locking
The starting point is structural g = 2 for a charged rotating soliton. In collective-coordinate language, the magnetic moment κ and the moment of inertia Λ satisfy
M κ = Λ
The structural g = 2 condition.
This is equivalent to a mixed-response statement. Writing the energy as
E(B, Ω) = M + ½ Λ Ω² − q κ Ω·B + ⋯
the condition becomes
∂²E/∂Ω_i∂B_j |₀ = −(q/M) ∂²E/∂Ω_i∂Ω_j |₀
The sharpening is to ask what this requires of the moduli-space geometry. Rotation acts through rotational Killing vectors \(K_i^a\). Electromagnetism acts through a U(1) connection whose magnetic response one-form is \(\Theta_{\rm EM}^i\). The moment of inertia is \(\Lambda_{ij} = g_{ab}K_i^aK_j^b\).
\(\Theta_{\rm EM}^i = (q/M) K_i^\flat\)
This is much stronger than Mκ = Λ alone. It identifies a specific one-form on moduli space and demands that it be fixed by the rotational Killing vector. Nothing about topology, Bogomolny saturation, or Kähler geometry alone forces this identification.
Part II — The Neutral Route and Its Closure
The Metric-Independent Topological Current
The most natural candidate for a bosonic mechanism is a soliton whose electromagnetic current is a conserved topological current:
\(J_{\rm EM}^\mu = q_t B^\mu, \qquad \partial_\mu B^\mu = 0\)
\(B^\mu\) is the degree current of the SU(2) hedgehog.
The Off-Shell Test
For the SU(2) hedgehog with unit winding, the topological density \(B^0(r)\) satisfies
\(4\pi \int_0^\infty r^2 B^0(r)\, dr = 1\)
Topology fixes the normalization.
But the magnetic first moment involves an extra factor of \(r^2\):
\(\mu_{\rm top} = (q_t/3)\langle r^2\rangle_B \Omega\)
\(\langle r^2\rangle_B = \int r^2 B^0(r)\, d^3x\)
The normalization integral \(\int B^0\, d^3x\) is topological. The first moment \(\int r^2 B^0\, d^3x\) is not. It depends on the profile of \(B^0(r)\), and therefore on the soliton shape.
The Measure Mismatch in BPS Skyrme
The BPS Skyrme model is the most favorable bosonic soliton to test. Its Lagrangian is
\(\mathcal L_{\rm BPS} = -\lambda^2\pi^4 B_\mu B^\mu – \mu^2 V(U)\)
On a BPS solution the two terms are pointwise equal, so the static mass is
\(M = 2\lambda^2\pi^4 \int \rho_B^2\, d^3x\)
The rotational inertia is
\(\Lambda = (4/3)\lambda^2\pi^4 \int r^2\rho_B^2\, d^3x\)
The topological magnetic moment is
\(\mathcal K = (q_t/3)\int r^2\rho_B\, d^3x\)
The missing-half condition \(\mathcal K = (q/2)(\Lambda/M)\) becomes
\(q_t \langle r^2\rangle_{\rho_B} = q \langle r^2\rangle_{\rho_B^2}\)
Two different moments of the profile.
Bogomolny saturation of the BPS Skyrme model does not, by itself, enforce the topological missing-half condition. The potential remains a deformation direction inside the BPS class, and it changes the two moments differently.
Failed Deformation Candidates
| Candidate | Reason it fails |
|---|---|
| \(F(X)\) with \(X_{\mu\nu} = -\tfrac12{\rm Tr}(L_\mu L_\nu)\) | No smooth algebraic scalar can satisfy \(F[U_0]=0\) and \(\delta_{\rm rot}F\neq0\). |
| \(W = \varepsilon^{\mu\nu\rho\sigma}{\rm Tr}(L_\mu L_\nu L_\rho L_\sigma)\) | Vanishes identically for SU(2): four one-forms in a three-dimensional Lie algebra. |
| \((B^\mu\partial_\mu B^2)^2\) | On the spherical rotor, \(B^i\partial_i B^2 = 0\) because the rotation is tangential to level surfaces of \(B^2\). |
| \(B^\mu B^\nu{\rm Tr}(\partial_\mu L_\nu)\) | Identically zero: \({\rm Tr}(L_\nu)=0\). |
| \(({\rm Tr}(L_\mu L_\nu)\partial^\mu B^\nu)^2\) | Vanishes at \(O(\Omega^2)\) on the hedgehog by symmetry of \(X_{ij}\) and antisymmetry of \(\partial_i v_j\). |
All these failures share a common geometric origin. For a spherical hedgehog, the rotation velocity \(v = \Omega \times x\) is tangential, and every invariant radial vector is proportional to \(n\). The contraction \(v\cdot n\) vanishes. Meanwhile the only invariant rank-two spatial tensor is symmetric, so it cannot contract with the antisymmetric rotation gradient.
The Profile-Preserving Deformation
The obstruction is broken by using the derivative of the topological current:
\(\mathcal O_B = B^\mu B^\nu\,{\rm Tr}(\partial_\mu L_\alpha \partial_\nu L^\alpha)\)
\(L_\alpha = U^{-1}\partial_\alpha U\).
Under a rigid rotation, the convective derivative rotates the spatial covector index of \(L_i\):
\(\mathcal D L_i = -(\partial_i v^j)L_j = -\omega_i{}^j L_j\)
After angular integration,
\(\int d^3x\,\mathcal O_B^{(2)} = \frac{16\pi}{3}\Omega^2 \int_0^\infty dr\, r^2\rho(r)^2\left(f’^2 + 2\frac{\sin^2 f}{r^2}\right)\)
The Neutral Non-Redundancy Proof
Evaluate on the true adiabatic rotating solution \(\phi_\Omega = \phi_0 + \Omega Z_{\rm rot} + \Omega^2\eta_2 + \cdots\). Because \(\mathcal O_B[\phi_0]=0\) and \(D\mathcal O_B[\phi_0]=0\), the quadratic matrix element is determined entirely by the rotational zero mode.
Suppose for contradiction that \(\mathcal O_B = E_A Y^A + \partial_\mu V^\mu\). On-shell, \(E_A=0\), so \(\mathcal O_B = \partial_\mu V^\mu\). Integrating over a closed rotational period T:
\(\int_0^T dt\int d^3x\,\partial_\mu V^\mu = \left[\int d^3x\,V^0\right]_0^T + \int_0^T dt\oint_\infty dS_i\,V^i\)
The spatial boundary term vanishes by localization. The temporal term vanishes for single-valued local \(V^0\) over a closed orbit. Therefore redundancy would imply \(\int_0^T dt\int d^3x\,\mathcal O_B = 0\). But the explicit matrix element is \(TC\Omega^2 + O(\Omega^3)\), nonzero.
For an SU(2) hedgehog whose electromagnetic coupling is supplied by a metric-independent topological current \(B^\mu\), current–metric locking cannot be protected solely by topology against arbitrary local Lorentz- and symmetry-preserving EFT deformations.
\(\mathcal O_B \notin \langle E_A\rangle + d\Omega^3_{\rm loc}\)
Proved Reproducible-here
Part III — The Charged Case: Setup
The Operator
If U is charged under the electromagnetic U(1), then \(J_{\rm EM}^\mu\) is a Noether current, not a topological current. The natural generalization is
\(\mathcal O_c = \mathcal B^\mu\mathcal B^\nu\,{\rm Tr}(\nabla_\mu L_\alpha \nabla_\nu L^\alpha)\)
\(\mathcal B^\mu\) is the gauge-invariant baryon current, \(L_\mu = U^\dagger D_\mu U\).
where the gauge-invariant baryon current must be derived from a fixed gauged action.
Part IV — Gate 1: The Mixed Hessian
The Corrected Expansion
On the static background at \(A=0\): \(\mathcal B^\mu = (\rho, 0)\), \(L_0=0\), \(L_i=l_i\), \(X_{00}^{(0)}=0\), \(X_{0i}^{(0)}=0\), \(X_{ij}^{(0)}={\rm Tr}(l_i l_j)\).
Introduce two ordinary parameters s, t:
\(U_{s,t}(x) = A_s(t)U_0(x)A_s^\dagger(t), \qquad A_\mu = t\, a_\mu^{(B)}\)
with \(A_s^\dagger\dot A_s = s\omega\) and \(a_i = \tfrac12(B_{\rm ext}\times x)_i\). Then
\(D^2S_c[Z_\Omega, Z_B] = \partial^2/\partial s\,\partial t \int d^4x\,\mathcal O_c(s,t)|_{s=t=0}\)
At \(s=0\), the configuration is static for all t. Therefore \(\nabla_0 L_i = 0\) for all t, and hence \(\delta_B\nabla_0 L_i = 0\). The standard gauge-invariant baryon current gives \(\delta_B\mathcal B^i = 0\) on the static background. The mixed Hessian becomes
\(D^2S_c[Z_\Omega, Z_B] = 2\rho^2{\rm Tr}(\delta_\Omega Y_{0\alpha}\delta_B Y_0{}^\alpha) + 2\rho\,\delta_\Omega\mathcal B^i\,\delta_B X_{i0} + 2\rho\,\delta_B\mathcal B^i\,\delta_\Omega X_{i0}\)
All three terms vanish. The first because \(\delta_B Y_0{}^\alpha = 0\). The second because \(\delta_B X_{i0} = {\rm Tr}(Y_{i\alpha}^{(0)}\delta_B Y_0{}^\alpha) = 0\). The third because \(\delta_B\mathcal B^i = 0\).
\(D^2S_c[Z_\Omega, Z_B] = 0, \qquad D^2S_c[Z_\Omega, Z_\Omega] \neq 0\)
The vanishing is kinematic. It follows from the structure of the mixed Hessian and the staticity of the magnetic tangent.
Proved Reproducible-here
The earlier implication \(\delta_B X_{00}=0 \Rightarrow \delta_\Omega\delta_B X_{00}=0\) was invalid. The correct chain uses \(\delta_B Y_{0\alpha}=0\), which follows from the staticity of the magnetic tangent at s = 0. The earlier treatment of \(\delta_\Omega\nabla_0 L_i = 0\) was also wrong: the rotational tangent is not a time-independent isorotation. The corrected argument gives the same result for the right reasons.
Part V — The Source-Derived Current
The Fixed Action
Fix the action:
\(S = S_{\rm Sk}[U,A] + S_{\rm Maxwell}[A] + S_{\rm gWZ}[U,A,\mathcal B_\mu]\)
where \(\mathcal B_\mu\) is a background source for baryon number. The gauge-invariant baryon current is defined by
\(\mathcal B^\mu_{\rm GI} = \delta S_{\rm gWZ}/\delta\mathcal B_\mu|_{\mathcal B=0}\)
The standard descent gives
\(\mathcal B^\mu_{\rm GI} = B^\mu + \frac{e}{8\pi^2}\varepsilon^{\mu\nu\rho\sigma}\partial_\nu[A_\rho{\rm Tr}(QL_\sigma)] + \frac{1}{16\pi^2}\varepsilon^{\mu\nu\rho\sigma}A_\nu F_{\rho\sigma}{\rm Tr}(Q^2) + O(A^2,\partial A)\)
Variation on the Static Background
At \(A=0\), the background is static: \(L_0=0\), and \(\partial_0\) of any static quantity is zero.
Goldstone–Wilczek term
\(\delta_B\mathcal B^i_{GW} = \frac{e}{8\pi^2}\varepsilon^{i\nu k\sigma}\partial_\nu{\rm Tr}(QL_\sigma)|_{A=0}\)
For the epsilon tensor to be nonzero, \(i,k,\sigma,\nu\) must be distinct. Since \(i,k,\sigma\) are spatial, \(\nu=0\). Then \(\partial_0\) of a static quantity vanishes.
\(\delta_B\mathcal B^i_{GW} = 0\)
Bardeen term
\(\delta_B\mathcal B^i_{\rm Bardeen} = \frac{1}{16\pi^2}\varepsilon^{i\nu\rho\sigma}[\delta A_\nu F_{\rho\sigma} + A_\nu\delta F_{\rho\sigma}]{\rm Tr}(Q^2)|_{A=0}\)
At \(A=0\), both \(A_\nu=0\) and \(F_{\rho\sigma}=0\), so both terms vanish.
\(\delta_B\mathcal B^i = 0\) for the GW+Bardeen current derived from the fixed gWZ action.
This is the current of a specific action, not an arbitrary ansatz. The index structure excludes local gauge-invariant improvements.
Proved Reproducible-here
Part VI — The Principal-Symbol Obstruction
Reduction to a Local Test
The closed-orbit argument does not carry over to the zero-frequency adiabatic setting, because the collective configuration is not an exact four-dimensional solution. The correct local test is the off-shell jet-space identity:
\(\mathcal O_c – E_A Y^A – \partial_\mu V^\mu \equiv 0\)
The best first attack is the principal time-derivative symbol.
The Quadratic Symbol of \(\mathcal O_c\)
Write \(U = U_0 e^\xi\), so \(\delta L_\mu = D_\mu\xi\). At principal order \(\delta L_\mu \approx \partial_\mu\xi\). On a static background, \(B^\mu=(\rho,0)\). For a plane-wave fluctuation \(\xi = v\,e^{-i\omega t + ikz}\),
\(\delta L_0 \approx -i\omega v, \qquad \delta L_3 \approx ikv\)
The principal contraction is the Minkowski sum over \(\alpha\):
\(\partial_0\partial_0\xi = -\omega^2\xi, \qquad \partial_0\partial_3\xi = \omega k\,\xi, \qquad \partial_0\partial_{1,2}\xi = 0\)
\({\rm Tr}(\partial_0 L_\alpha\,\partial_0 L^\alpha) \propto \omega^4 – \omega^2 k^2 = \omega^2(\omega^2 – k^2)\)
Therefore
\(P_{c,\rm prin} \propto \rho^2\omega^2(\omega^2 – k^2)|v|^2\)
The quadratic principal symbol of \(\mathcal O_c\) is not only \(p_0^2|p|^2\). The \(\alpha=0\) term contributes a \(p_0^4\) piece. This was invisible in the rigid-rotor calculation because there \(L_0=O(\Omega)\) and its convective derivative is \(O(\Omega^2)\). For arbitrary high-frequency fluctuations it must be retained.
The Skyrme Characteristic Matrix at \(p \parallel n\)
At a point on the hedgehog, choose the spatial 3-axis along n. The background Maurer–Cartan forms have
\(X_T = \frac{\sin^2 f}{r^2}, \qquad X_R = f’^2\)
Let A be the sigma-model coefficient and C the Skyrme coefficient. For \(p \parallel n\), the principal quadratic form diagonalizes by internal polarization.
\(H_R(\omega,k) = [A + 2CX_T](\omega^2 – k^2)\)
Radial polarization. Characteristic: \(\omega_R^2 = k^2\).
\(H_T(\omega,k) = [A + C(X_T+X_R)]\omega^2 – [A+CX_T]k^2\)
Transverse polarization. Characteristic: \(\omega_T^2 = \frac{A+CX_T}{A+C(X_T+X_R)}k^2\).
The sigma model alone is luminal: \(P_{c,\rm prin} \propto (\omega^2 – k^2)\), characteristic \(\omega^2 = k^2\), both vanish simultaneously. The Skyrme term is what splits the transverse cone away from Minkowski while \(P_{c,\rm prin}\) retains the Minkowski factor. The obstruction comes from the Skyrme term.
The Transverse Obstruction
For the radial mode, \(\omega_R^2=k^2\), so \(P_{c,\rm prin}(\omega_R,k)=0\). No obstruction.
For a transverse characteristic mode,
\(\omega_T^2 – k^2 = -\frac{CX_R}{A+C(X_T+X_R)}k^2\)
Therefore
\(v_T^\dagger P_{c,\rm prin} v_T \propto -\rho^2\frac{CX_R[A+CX_T]}{[A+C(X_T+X_R)]^2}k^4|v_T|^2\)
At a generic point of a nontrivial hedgehog, \(\rho \neq 0\) and \(X_R = f’^2 \neq 0\), and with \(A,C > 0\),
\(v_T^\dagger P_{c,\rm prin}(\omega_T,k)v_T \neq 0\)
Derived Reproducible-here
For the standard B = 1 hedgehog, \(f(r) = \pi + ar + O(r^3)\), so \(f'(0) = a\) can be nonzero. Then \(X_R \to a^2\) and \(X_T \to a^2\), and the baryon density approaches a finite nonzero limit. The obstruction need not disappear at the center. What becomes isotropic there is \(X_R = X_T\), not \(X_R = 0\). The \(X_R = 0\) limit is an artificial local diagnostic, not the hedgehog-center limit.
Part VII — The Divergence Loophole Removed
The Problem with the Integrated Argument
If \(\mathcal O_c = E_A Y^A + \partial_\mu V^\mu\), then on an exact periodic on-shell solution the integrated \(\mathcal O_c\) would vanish. But the zero-frequency collective configuration is not an exact four-dimensional solution. On it, \(E_A \neq 0\) at the relevant higher adiabatic order, so the EOM piece and the divergence piece are evaluated on two different configurations. They do not form a contradiction.
The Euler Operator Test
Apply the Euler–Lagrange operator to the proposed identity. Since the Euler operator annihilates local divergences identically,
\(\mathcal E_A(\partial_\mu V^\mu) \equiv 0\)
redundancy requires
\(\mathcal E_A(\mathcal O_c) = \mathcal E_A(E_B Y^B)\)
At quadratic order around the static background, if
\(S_c^{(2)} = \tfrac12\int \xi^\dagger P_c(\partial)\xi\)
then its Euler derivative is essentially the formally self-adjoint operator \(P_c\). A divergence has disappeared automatically. For an infinitesimal field redefinition with linearization R, the quadratic EOM-exact contribution has Euler operator
\(P_{\rm red} = H^\dagger R + R^\dagger H\)
Now the characteristic-kernel argument becomes legitimate without any \(V^\mu\). If \(Hv=0\), then because the Hessian principal symbol is self-adjoint, \(v^\dagger H^\dagger = 0\). Hence
\(v^\dagger P_{\rm red}v = 0\)
But the transverse Skyrme characteristic gives
\(v_T^\dagger P_{c,\rm prin} v_T \propto -\rho^2\frac{CX_R(A+CX_T)}{[A+C(X_T+X_R)]^2}k^4|v_T|^2 \neq 0\)
\(\mathcal O_c \neq E_A Y^A + \partial_\mu V^\mu\)
The total-divergence loophole is removed by the Euler operator without constructing \(V^\mu\). The matter-sector EOM/IBP redundancy is excluded at principal order. The argument is a full local-cohomology argument, not a high-frequency approximation: an exact operator identity would imply principal-symbol equality at highest homogeneous degree, and that fails.
Derived Reproducible-here
Part VIII — The Gauss-Reduced Physical Pencil
Coulomb Gauge and the Gauss Constraint
Impose the Coulomb gauge condition \(\partial_i A_i = 0\) as a gauge choice. This sets the longitudinal component \(A_L = 0\). The residual gauge freedom is time-independent gauge transformations, fixed by requiring \(A_0 \to 0\) at spatial infinity.
The Gauss constraint is not \(\partial_i\dot A_i = 0\); it is
\(-\nabla^2 A_0 = \rho_{\rm matter}(\xi)\)
where \(\rho_{\rm matter}\) is the linearized charge density of the matter fluctuation. At fixed nonzero spatial momentum k, this gives
\(A_0 = \frac{\rho_{\rm matter}(\xi)}{k^2}\)
So \(A_0\) is a constrained field determined instantaneously by the matter fluctuation. It is not an independent dynamical degree of freedom.
The earlier claim that temporal gauge plus \(\partial_i A_i = 0\) immediately gives the physical sector was too quick. In the coupled charged theory, Gauss’s law is \(\partial_i E_i = J^0_{\rm matter}\), so the longitudinal electric field participates in the constraint and is sourced by \(\xi\). The correct reduction is Coulomb gauge plus solving the Gauss constraint for \(A_0\).
The Physical Degrees of Freedom
After Coulomb gauge fixing and solving Gauss’s law, the physical dynamical fields are
\((\xi^a, A_T^i)\)
with \(\xi\) a three-component matter fluctuation and \(A_T\) the two transverse photon polarizations. Total: five degrees of freedom.
The Physical Pencil
The linearized equations for the physical fields take the form
\(\mathbb H_{\rm phys}(e,\omega,k)v = 0, \qquad \mathbb H_{\rm phys} = \omega^2 K_{\rm phys}(e,k) – S_{\rm phys}(e,k)\)
The kinetic matrix at \(e=0\)
At \(e=0\), the matter and transverse photon sectors decouple. The kinetic matrix is block diagonal:
\(K_{\rm phys}(0,k) = {\rm diag}(K_T, K_T, K_R, 1, 1)\)
\(K_T = A + C(X_T + X_R), \qquad K_R = A + 2CX_T\)
Both are positive since \(A,C > 0\) and \(X_T, X_R \geq 0\). The last two entries are the standard Maxwell kinetic coefficients.
\(K_{\rm phys}(0,k)\) is positive definite and invertible.
Derived Reproducible-here
Continuity in \(e\)
The covariant derivative introduces the coupling \(D_\mu\xi = \partial_\mu\xi – ieA_\mu[Q,\xi]\). At fixed k, the coupling between matter and transverse photons enters at \(O(e)\). The Coulomb backreaction through \(A_0 = \rho_{\rm matter}/k^2\) enters at \(O(e^2)\). Both are bounded on the physical sector for a smooth static background. Therefore
\(K_{\rm phys}(e,k) = K_{\rm phys}(0,k) + O(e), \qquad S_{\rm phys}(e,k) = S_{\rm phys}(0,k) + O(e)\)
Since \(K_{\rm phys}(0,k)\) is positive definite, its eigenvalues are bounded below by a positive constant. Small perturbations preserve invertibility:
\(K_{\rm phys}(e,k)\) is invertible for sufficiently small \(e\).
Part IX — Small-Coupling Persistence (Conditional)
The Reduced Matrix
Define
\(\mathbb N(e,k) = K_{\rm phys}(e,k)^{-1}S_{\rm phys}(e,k)\)
This is continuous in \(e\) on the physical sector.
The Spectral Gap at \(e=0\)
At \(e=0\), the transverse matter cluster has eigenvalue
\(\lambda_T = \omega_T^2 = \frac{A+CX_T}{A+C(X_T+X_R)}k^2\)
of multiplicity two, isolated from the radial matter branch and the transverse photon branch by
\(\Delta = \frac{CX_R}{A+C(X_T+X_R)}k^2 > 0\)
The Riesz Projector Argument
Choose a contour \(\Gamma\) surrounding \(\lambda_T\) and no other eigenvalue. Define
\(\Pi_T(e) = \frac{1}{2\pi i}\oint_\Gamma (z – \mathbb N(e,k))^{-1}\,dz\)
For sufficiently small \(e\), \(\Pi_T(e)\) exists, satisfies \(\Pi_T(e) \to \Pi_T(0)\), and has rank 2. Conditional on the asserted continuation
The Quadratic Form on the Cluster
At \(e=0\),
\(P_c(0)|_{{\rm Ran}\,\Pi_T(0)} = \gamma\,\mathbf 1_2\)
\(\gamma \propto -\rho^2\frac{CX_R(A+CX_T)}{[A+C(X_T+X_R)]^2}k^4 \neq 0\)
By continuity,
\(\Pi_T(e)P_c(e)\Pi_T(e) = \gamma\,\Pi_T(e) + O(e)\)
For sufficiently small \(e\), this restricted quadratic form is nondegenerate on the entire perturbed two-dimensional cluster. Conditional on the asserted continuation
The coupled static and rotating branch \(\Phi_e(\Omega)\); the linearized operator \(D\mathscr F\) on weighted Sobolev spaces; its Fredholm invertibility after zero-mode projection; the smoothness of the Riesz projector in \(e\). These are the standard elements of the continuation argument, but they have not been reconstructed in this record. Until they are, the small-e theorem is conditional on them.
Part X — The O(e) Block Identities
The Three Identities
The target is
\(K_1^{mm} = 0, \qquad S_1^{mm} = 0, \qquad P_1^{mm} = 0.\)
If all three hold, then
\(N_1 = K_0^{-1}S_1 – K_0^{-1}K_1 N_0\)
is matter–photon off-diagonal, so for every matter vector \(v\),
\(N_1 v \in \mathcal H_\gamma.\)
The first-order correction to a transverse matter eigenvector is purely photonic:
\(w^{(1)} = -Q(N_0 – \lambda_T)^{-1}Q N_1 v \in \mathcal H_\gamma.\)
Then \(P_0 w^{(1)} = 0\) because \(P_0\) acts only on the matter sector, and \(v^\dagger P_1 v = 0\) from the block condition. Therefore
\(v(e)^\dagger P(e)v(e) = \gamma + O(e^2).\)
The Structural Argument for \(K_1^{mm} = S_1^{mm} = 0\)
The quadratic action at \(e=0\) is block diagonal. At \(O(e)\), the only source of coupling is the covariant derivative \(D_\mu U = \partial_\mu U – ie\,a_\mu[Q,U]\). Every explicit \(\partial_e\) at \(e=0\) introduces exactly one gauge fluctuation \(a_\mu\), provided:
- The background matter field has no \(O(e)\) displacement.
- The background gauge potential starts at \(O(e)\).
Both hold: the Coulomb field \(A_0^{(0)}\) is \(O(e)\), and the profile shift is \(O(e^2)\). Therefore \(H_1\) is block off-diagonal with no matter–matter component.
Gauss reduction. The constrained variable satisfies \(a_0 = e\,G\,\xi + \cdots\). Substituting back produces \(e^2\,\xi G\xi\), not \(e\,\xi^2\). So the Gauss reduction preserves \(H_1^{mm} = 0\).
The \(P_1^{mm}\) Check
The operator is \(\mathcal O_c = \mathcal B^\mu \mathcal B^\nu\,{\rm Tr}(\nabla_\mu L_\alpha \nabla_\nu L^\alpha)\). The expansion of \(L_\mu\) and \(\nabla_\mu L_\alpha\) yields only \(e\,a\xi\) terms at \(O(e)\), never \(e\,\xi^2\). Therefore
\(P_1^{mm} = 0.\)
Conclusion
\(K_1^{mm} = 0, \qquad S_1^{mm} = 0, \qquad P_1^{mm} = 0.\)
Therefore \(\delta\lambda_T^{(1)} = 0\), \(\delta\gamma^{(1)} = 0\), and the leading deterioration is \(O(e^2)\).
The Second-Order Effective Operator
\(N_{\rm eff}(e) = \lambda_T\Pi_T + e^2\left[\Pi_T N_2 \Pi_T – \Pi_T N_1 Q (QN_0Q – \lambda_T)^{-1} Q N_1 \Pi_T\right] + O(e^3).\)
The radial–photon degeneracy at \(\lambda_R = \lambda_\gamma = k^2\) is not a singularity in the Schur complement for the transverse cluster. The resolvent is evaluated relative to \(\lambda_T\), and both the radial and photon states have denominator \(k^2 – \lambda_T = \Delta > 0\).
A term schematically written \((ea[Q,\xi])^2\) is not itself a matter–matter term: before eliminating \(a\), it is quartic in fluctuations. Direct \(N_2^{mm}\) terms come from \(O(e^2)\) background Coulomb/profile corrections and from the Gauss-reduced quadratic action.
Part XI — The Window-Size Specification (Draft)
The Frozen Input
The CAS-ready specification for the window-size calculation is:
\(U = U_0 e^\xi, \qquad A_0^{\rm bg} = eA_1(r), \qquad A_i^{\rm bg} = 0,\)
\(L_\mu = l_\mu + D_\mu\xi + \tfrac12[\xi,D_\mu\xi] + O(\xi^3),\)
\(R_\mu = U_0\left(l_\mu + \partial_\mu\xi + \tfrac12[\xi,\partial_\mu\xi]\right)U_0^\dagger + O(\xi^3),\)
together with one fixed explicit Goldstone–Wilczek current representative:
\(j_B^\mu = -\frac{1}{24\pi^2}\epsilon^{\mu\nu\alpha\beta}\left\{{\rm tr}(L_\nu L_\alpha L_\beta) – \frac{3ie}{2}\partial_\nu[A_\alpha{\rm tr}(\tau^3(L_\beta+R_\beta))]\right\}\)
and with the charge matrix fixed as \(Q = {\rm diag}(2/3, -1/3) = \tau_3/2 + \mathbf 1/6\).
Background Maurer–Cartan forms in the frozen local frame with \(n = e_3\):
\(l_1 = \sqrt{X_T}\,e_1, \qquad l_2 = \sqrt{X_T}\,e_2, \qquad l_3 = \sqrt{X_R}\,e_3,\)
\(X_T = \frac{\sin^2 f}{r^2}, \qquad X_R = f’^2.\)
One verified building block from a direct recomputation, useful as a cross-check for the CAS:
\(l_\theta|_{\rm pole} = i\left(\sin f\cos f\,\tau_1 + \sin^2 f\,\tau_2\right),\)
with \(-\tfrac12{\rm Tr}(l_\theta^2) = \sin^2 f\).
The Three Stages
- Unreduced local Hessian. Compute \(H_{0,1,2}\) and \(P_{0,1,2}^{\rm explicit}\) on the fixed background, retaining \(A_1, A_1’\) and any necessary background jets. Keep \(U_2\) entirely out.
- Gauss reduction. Construct the physical \(K, S, P\) pencil from the unreduced system.
- Profile response. Add \(D_{U_2}H_0\) and \(D_{U_2}P_0\) only when solving the physical \(O(e^2)\) window problem.
The Definitions
\(P_{\rm unred}(e) = P_0 + eP_1 + e^2\left(P_{2,\rm explicit} + D_{U_2}P_0\right) + O(e^3)\)
\(H_{\rm unred}(e) = H_0 + eH_1 + e^2\left(H_{2,\rm explicit} + D_{U_2}H_0\right) + O(e^3)\)
followed by Gauss reduction of the pair \((H, P)\).
The six classes (A, B, D, E, F, H) are useful schematically but should not be given to the CAS as an exhaustive list. The safest executable definition is
\(P_{2,\rm explicit}^{mm} = \tfrac12\left.\partial_e^2\frac{\delta^2\mathcal O_c}{\delta\xi\,\delta\xi}\right|_{e=0,\xi=0,a=0,U=U_0}\)
with the frozen input. The six classes are then cross-checks of the CAS expansion rather than assumptions about its completeness.
For a regular B = 1 hedgehog, \(f(r) = \pi + ar + O(r^3)\), so \(X_R \to a^2\) and \(X_T \to a^2\) at the center. The center is the isotropic limit \(X_R = X_T = a^2\), not \(X_R = 0\). The \(X_R = 0\) limit is an artificial local diagnostic.
Even at \(X_R = X_T\), radial and transverse entries of \(P_{2,\rm explicit}^{mm}\) need not be equal. The electromagnetic structure introduces the fixed generator \(Q_{\rm iso} = \tau_3/2\) and the Coulomb gradient \(\nabla A_1 = A_1′(r)\hat r\), which can break the degeneracy. The correct check is covariance under the residual symmetry of the full background including the EM spurions.
For the unreduced fixed-background \(mm\) Hessian, \(a_\mu = 0\) means the photon fluctuation is zero, while \(A_0^{\rm bg} = eA_1\) remains. Compute \(P_{\rm unred}\) first. Gauss reduction comes afterward and uses the constraint derived from the ordinary quadratic action \(H\). Otherwise the explicit \(P_2^{mm}\) and the induced pullback through the Gauss constraint get mixed together.
Part XII — The Computational Boundary
Why the Calculation Stops Here
The explicit \(P_{2,\rm explicit}^{mm}\) matrix requires evaluating
\(\left.\frac{\delta^2}{\delta\xi^a\delta\xi^b}\left[J_B^\mu J_B^\nu\,{\rm Tr}(\nabla_\mu L_\alpha\nabla_\nu L^\alpha)\right]\right|_{\xi=a=0}\)
at \(O(e^2)\), with the fixed GW current and the frozen \(L, R\) expansion. This requires:
- explicit \(\mathfrak{su}(2)\) index contraction of the background \(l_i^a\) with the fluctuation \(\xi^a\),
- expansion of \(L_\mu + R_\mu\) in the local frame with \(k \parallel e_3\),
- the \(e^2\) GW current evaluated on the Coulomb background \(A_1(r)\), including \(A_1′(r)\),
- the derivative structure \(D_\mu\xi\), \(\partial_\mu\xi\), and their commutators.
Doing this by hand in text would produce errors that cannot be detected — sign errors in commutators, misplaced \(U_0\) conjugations, index mismatches, confusion between \(A_1\), \(A_1’\), and the constrained \(a_0\). Any one would propagate into the matrix and produce a wrong result that looks plausible.
The frozen input is unambiguous. The calculation is finite and local. The next nontrivial result — the explicit matrix \(P_{2,\rm explicit}^{mm}\) — requires a CAS with the \(\mathfrak{su}(2)\) algebra implemented. What has stopped here is the attempt to calculate the size of the neighborhood, not the existence result.
What Can Be Checked Once the Matrix Exists
- Hermiticity. The matrix should be Hermitian.
- Reduction at \(e=0\). It should reduce to \(P_0^{mm}\).
- Static limit. The \(\xi = 0\) limit should reproduce the static background.
- Residual symmetry. The matrix should transform covariantly under the residual symmetry of the full background including EM spurions, not simply radial = transverse.
- Invariant cross-check. The pole value \(l_\theta|_{\rm pole} = i(\sin f\cos f\,\tau_1 + \sin^2 f\,\tau_2)\) and the invariant \(-\tfrac12{\rm Tr}(l_\theta^2) = \sin^2 f\) should be reproduced by the background algebra used in the CAS input.
- Chirality cross-check. The Cartesian combination \(l_x – i l_y = \tfrac{i\sin f}{r}e^{if}\tau_-\) should be reproduced by the CAS background.
- Dominant term. Identify whether the Schur term or the direct \(N_2\) term is larger, and what the resulting scaling of \(\epsilon\) is.
Part XIII — Corrections Along the Way
The candidate \(W = \varepsilon^{\mu\nu\rho\sigma}{\rm Tr}(L_\mu L_\nu L_\rho L_\sigma)\) vanishes identically because four Maurer–Cartan one-forms live in a three-dimensional Lie algebra.
The candidate \(\mathcal O = {\rm Tr}(B^\mu B^\nu\partial_\mu L_\nu)\) is identically zero because \({\rm Tr}(L_\nu)=0\).
The implication \(\delta_B X_{00}=0 \Rightarrow \delta_\Omega\delta_B X_{00}=0\) was invalid. The correct chain uses \(\delta_B Y_{0\alpha}=0\), which follows from the staticity of the magnetic tangent.
The claim \(\delta_\Omega\nabla_0 L_i = 0\) was wrong. The collective rotational zero mode is not a time-independent isorotation; \(\delta_\Omega\nabla_0 L_i = [\omega, l_i]\) is one of the objects responsible for the neutral rotor matrix element.
The quadratic principal symbol of \(\mathcal O_c\) is not only \(p_0^2|p|^2\). The \(\alpha=0\) term contributes a \(p_0^4\) piece, invisible in the rigid-rotor calculation but essential for the principal-symbol test. For the plane wave, \(\partial_0\partial_0\xi = -\omega^2\xi\) and \(\partial_0\partial_3\xi = \omega k\,\xi\), giving the Minkowski sum \(\omega^4 – \omega^2 k^2 = \omega^2(\omega^2 – k^2)\).
The sigma model alone is luminal: \(P_{c,\rm prin} \propto (\omega^2 – k^2)\), characteristic \(\omega^2 = k^2\), both vanish simultaneously. The Skyrme term is what splits the transverse cone away from Minkowski while \(P_{c,\rm prin}\) retains the Minkowski factor. The obstruction comes from the Skyrme term.
For the standard B = 1 hedgehog, \(f(r) = \pi + ar + O(r^3)\), so \(f'(0) = a\) can be nonzero. The obstruction need not disappear at the center. What becomes isotropic there is \(X_R = X_T\), not \(X_R = 0\).
The earlier gauge-fixing argument using temporal gauge plus \(\partial_i A_i = 0\) was too quick. The correct reduction is Coulomb gauge plus solving Gauss’s law for \(A_0\). The physical kinetic block has the Skyrme-modified coefficients \(K_T = A + C(X_T+X_R)\) and \(K_R = A + 2CX_T\), both positive.
An earlier version suggested the physical coupling was probably inside the window based on an order-one prefactor estimate. That estimate was not supported. The existence theorem gives \(\epsilon > 0\); it does not give a naturalness bound on \(\epsilon\). No quantitative lower bound on \(\epsilon\) has been derived.
The statement \(P_1 = 0\) was too strong. The correct statement is \(P_1^{mm} = 0\), i.e., the matter–matter block vanishes. The \(O(e)\) correction is matter–photon off-diagonal. This is sufficient because it implies \(\Pi_T P_1 \Pi_T = 0\) and closes the radial-matter loophole.
The radial–photon degeneracy at \(\lambda_R = \lambda_\gamma = k^2\) is not a singularity in the Schur complement for the transverse cluster. The resolvent is evaluated at \(\lambda_T\), and both radial and photon states have denominator \(k^2 – \lambda_T = \Delta > 0\).
The term \((ea[Q,\xi])^2\) is quartic in fluctuations, not a quadratic Hessian term. Direct \(N_2^{mm}\) terms come from \(O(e^2)\) background Coulomb/profile corrections and from the Gauss-reduced quadratic action.
The statement \(\rho_{\rm matter} = e\,{\rm Tr}(Q[l_0,\xi])\) and the conclusion \(a_0 = O(e^2)\xi\) were both wrong. The linearized charge density generally contains time-derivative terms \(J^0_{\rm lin} \sim e\,\mathcal Q(U_0)\dot\xi\), even though \(l_0 = 0\). At Fourier frequency \(\omega\), \(a_0 \sim e\omega\mathcal Q\xi/k^2 + O(e^2)\). So \(a_0 = O(e)\xi\), and eliminating it still produces an \(O(e^2)\) matter–matter contribution.
The full physical matrices are \(K = K_0 + eK_1 + e^2K_2 + \cdots\) and \(S = S_0 + eS_1 + e^2S_2 + \cdots\). Only the matter–matter diagonal blocks have no \(O(e)\) term.
If \(K(e) = K_0 + eK_1 + e^2K_2 + \cdots\), then \(K_1\) is the coefficient of \(e\) and contains no additional \(e\). With \(D_\mu U = \partial_\mu U – ie a_\mu[Q,U]\), the \(O(e)\) block is \((K_1^{m\gamma})_{ai} = \kappa_{ai}\), not \(e\kappa_{ai}\).
One photon insertion from minimal coupling carries one explicit power of \(e\), not two. At quadratic fluctuation order, the \(e^2\) Hessian contributions must be classified by both coupling order and fluctuation degree. Terms such as \(e^2a^2\xi^2\) are fourth order in fluctuations and irrelevant to \(P^{(2)}\).
The “first-order projector correction” and “first-order eigenvector correction” are two representations of the same first-order movement of the subspace. Both vanish at \(O(e)\) under the block structure. At \(O(e^2)\), the pullback contains several pieces: \(P_{\rm eff}^{(2)} = V_0^\dagger P_2 V_0 + V_1^\dagger P_1 V_0 + V_0^\dagger P_1 V_1 + V_1^\dagger P_0 V_1 + V_2^\dagger P_0 V_0 + V_0^\dagger P_0 V_2\).
The baryon current should not be defined by the anomaly-divergence prescription. For vector baryon number in the two-flavor electromagnetic theory, \(U(1)_B\) is non-anomalous with respect to electromagnetism. The correct definition is by source variation: \(J_B^\mu = \delta S_{\rm fixed}[U,A,\mathcal B]/\delta\mathcal B_\mu|_{\mathcal B=0}\).
The identity piece of \(Q\) drops from the commutator \([Q,U]\) in \(D_\mu U\), but does not drop from traces such as \({\rm Tr}(Q^2)\) or from source/WZ couplings. The standard two-flavor choice is \(Q = {\rm diag}(2/3, -1/3) = \tau_3/2 + \mathbf 1/6\).
The proposed expansion of \(L_\beta + R_\beta\) at \(O(\xi^2)\) was wrong. The conjugating \(U = U_0 e^\xi\) itself fluctuates, so one cannot obtain \(R_\beta^{(2)}\) simply by conjugating \(L_\beta^{(2)}\) with \(U_0\). The correct expansion is given in the frozen input above.
The statement “the topological current has no explicit \(e\), so it does not contribute to \(P_2^{mm}\)” is false once evaluated on the \(e\)-dependent background. It does contribute indirectly through \(U_2\), and that contribution belongs to the background-response sector \(P_{2,\rm bg}^{mm}\).
Even if the Bardeen contribution to \(J_B^\mu\) is \(U\)-independent, the product \(J_B^\mu J_B^\nu X_{\mu\nu}\) acquires a matter Hessian from the \(U\)-independent \(J_B\) multiplying the \(\xi\)-dependence of \(X_{\mu\nu}\). So “its \(\xi\)-variation is zero” is not sufficient to conclude “it contributes nothing to \(P_2^{mm}\).”
The direct calculation of the transverse Maurer–Cartan form at the pole, under the convention \(U_0 = \cos f + i(\tau\cdot n)\sin f\), gives
\(l_\theta|_{\rm pole} = i\left(\sin f\cos f\,\tau_1 + \sin^2 f\,\tau_2\right).\)
The transcript text as received reports the pole value as \(i(\tfrac12\sin^2 f\,\tau_1 + \sin^2 f\,\tau_2)\). The two forms differ in the \(\tau_1\) coefficient: \(\sin f\cos f = \tfrac12\sin 2f\) versus \(\tfrac12\sin^2 f\). These are different functions of \(f\); no generator normalization reconciles them.
The invariant \(-\tfrac12{\rm Tr}(l_\theta^2) = \sin^2 f\) holds for the direct-calculation form. For the transcript-text form, \(-\tfrac12{\rm Tr}(l_\theta^2) = \tfrac54\sin^4 f\), which fails the invariant except when \(\sin^2 f = 4/5\). The invariant cleanly distinguishes the two.
The most plausible explanation is a \(\sin 2f \to \sin^2 f\) transcription slip inside the transcript text, not an error in the underlying session. The direct-calculation value is the correct one and is Reproducible-here. The exact form of the transcript’s quoted string is a property of the transcript, not of the mathematics.
The small-e charged theorem has two logically distinct parts. The e = 0 cohomological anchor — Parts IV–VII, comprising Gate 1, the source-derived current check, the principal-symbol obstruction, and the divergence-loophole removal — is Reproducible-here. The continuation portion — existence and smoothness of the coupled rotating branch in e, Fredholm invertibility of the linearized operator on weighted spaces after zero-mode projection, and the smoothness of the Riesz projector — is Asserted-not-inspectable. The joint theorem inherits the weaker label.
An earlier hand attempt at the circular combination \(l_x – i l_y\) used
\(l_y = \tfrac1r(-s^2\tau_1 + i s c\,\tau_2), \qquad s = \sin f,\ c = \cos f,\)
which is not anti-Hermitian: the \(-s^2\tau_1/r\) piece is Hermitian. The correct expression, from \(l_y = U_0^\dagger\partial_y U_0\) at the pole with \(\partial_y n = e_2/r\), is
\(l_y = \tfrac{i}{r}(-s^2\tau_1 + s c\,\tau_2).\)
With the corrected pair, \(l_x – i l_y = \tfrac{s}{r} e^{if}(i\tau_1 + \tau_2) = \tfrac{i\sin f}{r} e^{if}\tau_-\). The single-chirality structure and the \(e^{if}\) phase are therefore Reproducible-here. The exact transcript string \(2\sin f\,e^{if}\) and any claim about its derivation remain Asserted-not-inspectable.
Part XIV — Addendum: Pole Phase-Lock Structure
Purpose
This addendum records a background-algebra result that has been independently reconstructed in this record: the single-chirality, \(e^{if}\)-phase structure of the transverse Maurer–Cartan combination at the pole. It also clarifies the attribution of Correction 23 and flags an open structural subtlety about the transverse fluctuation at the pole.
Section 1 — Clarification on Correction 23
Correction 23’s substantive claim is correct with respect to the transcript text as received: the transcript’s quoted pole value of \(l_\theta\) differs from the direct calculation. Correction 23 already gives the direct-calculation value \(i(\sin f\cos f\,\tau_1 + \sin^2 f\,\tau_2)\), which is the correct form. It attributes the \(\tfrac12\sin^2 f\) form to the transcript. If the underlying session produced \(\sin f\cos f\), then the discrepancy is inside the transcript’s transcription, and the correct action is to reword Correction 23’s attribution rather than overturn it. The invariant check confirms the direct-calculation form and the failure of the \(\tfrac12\sin^2 f\) form.
Section 2 — Direct value of \(l_\theta\)
Under \(U_0 = \cos f + i(\tau\cdot n)\sin f\), at the north pole \(\theta = 0\), \(\varphi = 0\):
\(l_\theta|_{\rm pole} = i(\sin f\cos f\,\tau_1 + \sin^2 f\,\tau_2).\)
The \(\tau_1\) coefficient is \(\sin f\cos f = \tfrac12\sin 2f\). It is independent of the left- or right-acting Maurer–Cartan convention.
Derived Reproducible-here
Section 3 — Invariant check
The invariant \(-\tfrac12{\rm Tr}(l_\theta^2) = \sin^2 f\) holds for the form above in the Pauli convention \(\mathrm{Tr}(\tau_a\tau_b) = 2\delta_{ab}\):
\(l_\theta^2 = -\sin^2 f\cos^2 f\,\mathbf 1 – \sin^4 f\,\mathbf 1 = -\sin^2 f\,\mathbf 1.\)
The alternative \(\tfrac12\sin^2 f\) form gives \(l_\theta^2 = -\tfrac14\sin^4 f\,\mathbf 1 – \sin^4 f\,\mathbf 1 = -\tfrac54\sin^4 f\,\mathbf 1\), hence \(-\tfrac12{\rm Tr}(l_\theta^2) = \tfrac54\sin^4 f\), which fails the invariant except when \(\sin^2 f = 4/5\). The invariant cleanly distinguishes the two forms and confirms the Section 2 value.
Derived Reproducible-here
Section 4 — Circular combination and phase-lock
Direct Cartesian calculation at the pole, with \(\partial_x n = e_1/r\), \(\partial_y n = e_2/r\), gives
\(l_x = \tfrac{i}{r}(\sin f\cos f\,\tau_1 + \sin^2 f\,\tau_2),\)
\(l_y = \tfrac{i}{r}(-\sin^2 f\,\tau_1 + \sin f\cos f\,\tau_2).\)
Consequently,
\(l_x – i l_y = \tfrac{i\sin f}{r} e^{if}\tau_- = \tfrac{2i\sin f}{r} e^{if} T_-,\)
with \(T_- = \tau_-/2\).
The single-chirality structure and the \(e^{if}\) phase are reproducible here. The factor \(2\) appears only when using \(T_-\). The overall \(i/r\) factor is not part of the transcript’s bare coefficient; whether the transcript’s exact statement \(2\sin f\,e^{if}\) referred to the coefficient after stripping the conventional \(i/r\) factor cannot be determined without the underlying calculation.
Derived Reproducible-here for the \(e^{if}\tau_-\) structure. The exact transcript string remains Asserted-not-inspectable.
Section 5 — Open item: the transverse fluctuation at the pole
A transverse fluctuation of the soliton at the pole is like a p-orbital vanishing at its origin: its value vanishes, its angular derivative does not. The well-defined object at the pole is the derivative of the transverse components in the \(x, y\) directions, not their value. This was identified during the session and flagged, not resolved. Any phase-locked ansatz for the transverse fluctuation must be built with this distinction explicit from the start.
Open
Section 6 — What the addendum does not establish
- The “twice the rate” precession claim. The \(e^{if}\) phase in the Maurer–Cartan form implies a covariant derivative with phase rate \(f’\), not \(2f’\), unless the comparison is to a different quantity. The claim requires its own derivation.
- The exact transcript string \(2\sin f\,e^{if}\). The mathematical form \(l_x – i l_y = \tfrac{i\sin f}{r} e^{if}\tau_-\) is reproducible here. Whether the transcript stripped the \(i/r\) factor and how it named the coefficient cannot be determined.
- The remaining transcript-reported items — \(l_\varphi\), \(\nabla_\mu l_\alpha\), any \(e^2\) coefficient — remain asserted-not-inspectable.
Closing State
The derivation produced the following frozen status.
| Claim | Logical status | Evidentiary basis |
|---|---|---|
| Neutral topological-current non-protection lemma | Proved | Reproducible-here |
| Gate 1: mixed Hessian vanishes | Proved | Reproducible-here |
| Source-derived current check | Proved | Reproducible-here |
| Principal-symbol cohomological obstruction | Derived | Reproducible-here |
| Divergence loophole removed by Euler operator | Derived | Reproducible-here |
| \(O(e)\) block identities \(K_1^{mm} = S_1^{mm} = P_1^{mm} = 0\) | Derived | Reproducible-here |
| Pole value \(l_\theta|_{\rm pole} = i(\sin f\cos f\,\tau_1 + \sin^2 f\,\tau_2)\) | Derived | Reproducible-here |
| Invariant \(-\tfrac12{\rm Tr}(l_\theta^2) = \sin^2 f\) | Derived | Reproducible-here |
| Pole phase-lock structure \(l_x – i l_y = \tfrac{i\sin f}{r} e^{if}\tau_-\) | Derived | Reproducible-here |
| Small-e charged Skyrme non-protection theorem | Conditional | Anchor reproducible-here; continuation asserted-not-inspectable |
| Finite-k subprincipal transverse operator \(P_{\rm sub}^{(T)}\) | Open | Open |
| Circular-polarization cancellation within \(P_{\rm sub}^{(T)}\) | Open | Open |
| \(P_{2,\rm explicit}^{mm}\) | Not calculated | CAS required |
| \(D_{U_2}P_0^{mm}\) | Open | Requires \(f_2(r)\) |
| Numerical small-e window | Undetermined | CAS required |
| All-e continuation | Open | Open |
| The general response identity | Open | Open |
| Exceptional structures (SUSY, hidden symmetry, geometric locking) | Open | Open |
| Transcript string \(2\sin f\,e^{if}\) and any claim about its exact normalization | — | Asserted-not-inspectable |
| “Twice the rate” precession claim | — | Asserted-not-inspectable |
| Transcript-reported \(l_\varphi\), \(\nabla_\mu l_\alpha\), any \(e^2\) coefficient | — | Asserted-not-inspectable; excluded |
What Remains Open
- The coupled-branch continuation. Weighted-space setup, Fredholm invertibility, and Riesz-projector smoothness. Not displayed. The small-e theorem is conditional on them.
- The finite-k subprincipal transverse operator \(P_{\rm sub}^{(T)}\). Whether, after summing every contribution at the relevant symbol order, \(P_{\rm sub}^{(T)} = p_T I_2\) or contains a surviving \(p_A J_3\) with \(p_A \neq 0\). This is a question about the full local quadratic operator beyond its principal symbol; it does not affect the principal-symbol obstruction.
- The circular-polarization cancellation. Follows from the above.
- \(P_{2,\rm explicit}^{mm}\) and \(D_{U_2}P_0^{mm}\). Requires a CAS, with the frozen input above.
- The numerical size of the window. Requires the above.
- The transverse fluctuation at the pole. A transverse fluctuation vanishes at the pole like a p-orbital at its origin; the well-defined object is its derivative in the \(x, y\) directions, not its value. The phase-locked ansatz must be rebuilt with this distinction explicit.
- The “twice the rate” precession claim. The \(e^{if}\) phase implies a covariant derivative with phase rate \(f’\), not \(2f’\), unless the comparison is to a different quantity. Requires its own derivation.
- All-e continuation. The result holds for sufficiently small nonzero e, not for all e up to the physical coupling.
- The general response identity. The classification of local identities capable of enforcing \(\mathscr R_\Theta = (q/M)\mathscr R_g\) modulo EOM, total derivatives, and gauge identities is open.
- Exceptional structures. Whether any purely bosonic structure — supersymmetry, hidden symmetry, constrained operator algebra, geometric locking — can enforce current–metric locking is untouched.
The Honest Summary
The derivation produced a proved neutral lemma, a reproducible principal-symbol cohomological obstruction for the charged case, and a small-e charged theorem whose e = 0 anchor is reproducible but whose continuation portion is not. The pole value of the transverse Maurer–Cartan form has been independently verified, as has the invariant \(-\tfrac12{\rm Tr}(l_\theta^2) = \sin^2 f\) and the pole phase-lock structure \(l_x – i l_y = \tfrac{i\sin f}{r} e^{if}\tau_-\). The numerical window and the exceptional-structure question remain open. The remaining transcript-reported items are excluded pending inspectable output.
The problem is no longer “find a clever soliton profile that gives g = 2.” It is: does there exist a microscopic identity whose local response content forces the electromagnetic magnetic-response functional and the rotational kinetic functional to be the same functional up to q/M?