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2409.10998

Hyperuniformity in Regular Trees

Mattias Byléhn

correcthigh confidence
Category
Not specified
Journal tier
Strong Field
Processed
Sep 28, 2025, 12:56 AM

Audit review

The paper proves a non-geometric hyperuniformity theorem (Theorem 1.3) for all invariant locally square-integrable point processes on (q+1)-regular trees: either complementary-series mass forces super-volume growth, or principal-series mass forces a positive Cesàro lower bound, which implies limsup NV*μ(r)/|Br| > 0. This is established via Proposition 5.1 and the spherical transform of balls, and the proof explicitly splits by spectral type, covering all nontrivial cases . The candidate reproduces correct kernel identities and the two sharp lower bounds for atoms at 0, τ/2 and on the imaginary arcs, and a valid Cesàro argument for interior real spectrum, but incorrectly flags as a remaining possibility the case where the diffraction measure is supported entirely at the two removed boundary atoms {i/2, τ/2+i/2} (which would make NV* vanish). The paper’s argument shows one necessarily has nonzero principal or complementary diffraction in the nontrivial cases considered, and then concludes the desired positivity of limsup; see the NV* definition and spectral decomposition, the main theorem statement, and its proof line selecting ε with σ(p)μ((ε, τ/2−ε)) > 0 . Hence the model’s “incomplete” conclusion is unwarranted, while its partial calculations match the paper’s bounds.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} strong field

\textbf{Justification:}

The paper rigorously establishes non-geometric hyperuniformity for invariant locally square-integrable point processes on regular trees and ties number-variance growth to spectral features of the diffraction measure. The approach blends spherical harmonic analysis with quantitative bounds and provides instructive examples connected to Ramanujan graphs. The results are correct and clearly presented. Minor clarifications about the impossibility of boundary-only diffraction support in nontrivial cases would forestall confusion.