Sums of von Mangoldt convolutions via trace-sum averages over U(N)
Abstract
We study piecewise polynomial functions δk(c) that appear in the conjectured asymptotics for the variance of short-interval sums of von Mangoldt convolutions Λ*k. By a theorem of Kuperberg and Lalín, a unitary matrix integral involving a sum of trace products governs the large-q limit of the function-field analogue of this variance. We identify δk(c) as the leading-order coefficient of this integral when the total trace degree and matrix size grow with a fixed ratio c. Through an asymptotic analysis of two lattice-point representations for the matrix integral, we obtain explicit forms of δk(c). A finite spline expansion and a contour-integral representation expressing δk(c) as the inverse Laplace transform of a two-weight block Hankel determinant are also obtained.
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BibTeX
@misc{irfan2026sums,
title = {{Sums of von Mangoldt convolutions via trace-sum averages over $U(N)$}},
author = {Ayesha Irfan},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.33953},
eprint = {2609.33953},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.33953},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Sums of von Mangoldt convolutions via trace-sum averages over U(N)
AU - Ayesha Irfan
PY - 2026
DA - 2026/09/27
PB - arXiv
DO - 10.48550/arxiv.2609.33953
UR - https://arxiv.org/abs/2609.33953
AB - We study piecewise polynomial functions δ_k(c) that appear in the conjectured asymptotics for the variance of short-interval sums of von Mangoldt convolutions Λ^*k. By a theorem of Kuperberg and Lalín, a unitary matrix integral involving a sum of trace products governs the large-q limit of the function-field analogue of this variance. We identify δ_k(c) as the leading-order coefficient of this integral when the total trace degree and matrix size grow with a fixed ratio c. Through an asymptotic analysis of two lattice-point representations for the matrix integral, we obtain explicit forms of δ_k(c). A finite spline expansion and a contour-integral representation expressing δ_k(c) as the inverse Laplace transform of a two-weight block Hankel determinant are also obtained.
ER -