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LeanPool.Superdiffusion.Algsuperdiff.SuperdiffusivityFiniteMoments

Superdiffusivity with finite displacement moments #

This bridge intersects the thresholds from the quantitative theorem and its integrability companion. The displayed expectations therefore have integrable first and second displacement observables in the same small-coupling regime. The original quantitative theorem remains available with its unchanged statement.

theorem Algsuperdiff.superdiffusivity_with_finite_moments (d : ℕ) [NeZero d] (hd : 2 ≤ d) (cstar : ℝ) (hcstar : 0 < cstar) :
∃ (gamma0 : ℝ) (C : ℝ), 0 < gamma0 ∧ 0 < C ∧ ∀ (M : Section3.ABKModel d), Section3.Disorder.cstar M = cstar → M.gamma ≤ gamma0 → ∀ (t : ℝ), 0 < t → (∀ᵐ (omega : Section5.Field.FullSample d M.gamma) ∂↑(Section5.Field.fullSampleLaw M), MeasureTheory.Integrable (fun (path : MarkovProcess.ContinuousPath (OnePoint (HCPolySupport.Vec d))) => DivergenceFormProcess.Form.onePointRetract 0 (path t.toNNReal)) ((Section5.Field.streamExhaustionTailInput M omega).wholeSpaceProcess ↑0) ∧ MeasureTheory.Integrable (fun (path : MarkovProcess.ContinuousPath (OnePoint (HCPolySupport.Vec d))) => HCPolySupport.vecNormSq (DivergenceFormProcess.Form.onePointRetract 0 (path t.toNNReal))) ((Section5.Field.streamExhaustionTailInput M omega).wholeSpaceProcess ↑0)) ∧ ∀ (p : ℝ), 1 ≤ p → p ≤ C⁻¹ * M.gamma⁻¹ * |Real.log M.gamma| ^ (-6) → ∫⁻ (omega : Section5.Field.FullSample d M.gamma), ENNReal.ofReal |∫ (path : MarkovProcess.ContinuousPath (OnePoint (HCPolySupport.Vec d))), HCPolySupport.vecNormSq (DivergenceFormProcess.Form.onePointRetract 0 (path t.toNNReal)) ∂(Section5.Field.streamExhaustionTailInput M omega).wholeSpaceProcess ↑0 - 2 * ↑d * Section5.Support.intrinsicScale M.nu cstar M.gamma t ^ 2| ^ p ∂↑(Section5.Field.fullSampleLaw M) ≤ ENNReal.ofReal (C * (√p + √|Real.log M.gamma|) * √M.gamma * |Real.log M.gamma| ^ 4 * Section5.Support.intrinsicScale M.nu cstar M.gamma t ^ 2) ^ p ∧ ∫⁻ (omega : Section5.Field.FullSample d M.gamma), ENNReal.ofReal (HCPolySupport.vecNormSq (∫ (path : MarkovProcess.ContinuousPath (OnePoint (HCPolySupport.Vec d))), DivergenceFormProcess.Form.onePointRetract 0 (path t.toNNReal) ∂(Section5.Field.streamExhaustionTailInput M omega).wholeSpaceProcess ↑0)) ^ p ∂↑(Section5.Field.fullSampleLaw M) ≤ ENNReal.ofReal (C * (p + |Real.log M.gamma|) * M.gamma * |Real.log M.gamma| ^ 7 * Section5.Support.intrinsicScale M.nu cstar M.gamma t ^ 2) ^ p

One positive threshold gives both displacement integrability and the full quantitative superdiffusivity bounds, uniformly at every positive time.