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2111.11678

Reducibility of quantum harmonic oscillator on R^d perturbed by a quasi-periodic potential with logarithmic decay

Zhenguo Liang, Zhiqiang Wang

correcthigh confidence
Category
Not specified
Journal tier
Specialist/Solid
Processed
Sep 28, 2025, 12:56 AM

Audit review

The paper proves reducibility for the quantum harmonic oscillator on R^d with a quasi-periodic-in-time potential that decays logarithmically in space, under iota ≥ (n+d+1)/2, and obtains the quantitative bounds meas(D0\Dε) ≤ C ε^{1/6}, ‖W‖_{B(H^s)} ≤ Cε, and ‖Ψ^{±1}−Id‖_{B(H^p)} ≤ C ε^{5/12} for p∈[0,1]. The candidate solution reproduces the same KAM reducibility scheme in the Hermite basis, the same hypotheses and end-state (unitary, analytic conjugacy Ψ; block-diagonal W commuting with H0; and the same exponents). Minor presentational differences (e.g., how the matrix class and small-divisor conditions are described) do not affect correctness. Overall, the argument paths are essentially the same.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} specialist/solid

\textbf{Justification:}

The manuscript delivers a careful KAM reducibility result for the QHO under logarithmic spatial decay, sharpening prior work through a new homological-equation estimate. The structure is rigorous and the quantitative exponents are explicit and valuable. Minor clarifications of the parameter iteration and a concise comparison with the earlier framework would improve accessibility for readers entering from related KAM literature.