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2507.21457

Green’s function estimates for long-range quasi-periodic operators on Z^d and applications

Li Wen, Yuan Wu

correctmedium confidence
Category
Not specified
Journal tier
Strong Field
Processed
Sep 28, 2025, 12:57 AM

Audit review

The paper rigorously proves the multiscale Green’s function bounds for long-range QP operators with exp(−α log_ρ(1+‖·‖)) hopping, including the operator-norm control with the θ_s(E) factors and the off-diagonal kernel bound exp(−(α/2) log_ρ(1+‖x−y‖)) on s-good sets (Theorem 1.1) . Its proof hinges on a carefully structured Schur-complement reduction to 1–2 site cores, a Rouché-type construction of θ_s via detailed determinant estimates (e.g., (4.41)–(4.43) at the initial scale; and the higher-scale Schur complement Ss+1(z) decomposition) , together with quasi-metric/Combes–Thomas technology tailored to log^ρ tails (Lemma 3.1 and Lemma 3.4) . The candidate solution, while thematically similar (Schur complement + Neumann series), is flawed at key logical junctures: (i) it asserts existence of θ_s from the open mapping theorem for v(z)−E−U_s(z) without a valid small-perturbation argument (the paper uses Rouché for this purpose), (ii) it postulates a diagonal “self-energy” U_s(θ+n·ω) independent of the ambient block arrangement without proof, and (iii) it applies a uniform Lipschitz smallness condition Lip(U_s) ≤ (κ1/2)‖x+θ_s‖_T on the whole domain, which cannot hold uniformly over x; the paper instead localizes the analysis to small cores to avoid precisely these pitfalls. Consequently, the model’s proof outline misses essential prerequisites and justifications that are supplied in the paper.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} strong field

\textbf{Justification:}

The paper provides a careful multiscale analysis for long-range QP operators with log\^ρ hopping, producing sharp Green’s function bounds and consequential spectral/dynamical applications. The technical execution (small-core Schur complements, Rouché at each scale, quasi-metric Combes–Thomas) is well controlled. Minor clarifications in exposition would improve accessibility without altering substance.