Circulant graphs as an example of discrete quantum unique ergodicity

Fuente: arXiv
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Main Authors: Harrison, Jon, Pruss, Clare
Format: Preprint
Published: 2024
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author Harrison, Jon
Pruss, Clare
author_facet Harrison, Jon
Pruss, Clare
contents A discrete analog of quantum unique ergodicity was proved for Cayley graphs of quasirandom groups by Magee, Thomas and Zhao. They show that for large graphs there exist real orthonormal basis of eigenfunctions of the adjacency matrix such that quantum probability measures of the eigenfunctions put approximately the correct proportion of their mass on subsets of the vertices that are not too small. We investigate this property for Cayley graphs of cyclic groups (circulant graphs). We observe that there exist sequences of orthonormal eigenfunction bases which are perfectly equidistributed. However, for sequences of 4-regular circulant graphs of prime order, we show that there are no sequences of real orthonormal bases where all sequences of eigenfunctions equidistribute. To obtain this result, we also prove that, for large 4-regular circulant graphs of prime order, the maximum multiplicity of the eigenvalues of the adjacency matrix is two.
format Preprint
id arxiv_https___arxiv_org_abs_2411_09028
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Circulant graphs as an example of discrete quantum unique ergodicity
Harrison, Jon
Pruss, Clare
Mathematical Physics
81Q50, 05C50, 58J51
A discrete analog of quantum unique ergodicity was proved for Cayley graphs of quasirandom groups by Magee, Thomas and Zhao. They show that for large graphs there exist real orthonormal basis of eigenfunctions of the adjacency matrix such that quantum probability measures of the eigenfunctions put approximately the correct proportion of their mass on subsets of the vertices that are not too small. We investigate this property for Cayley graphs of cyclic groups (circulant graphs). We observe that there exist sequences of orthonormal eigenfunction bases which are perfectly equidistributed. However, for sequences of 4-regular circulant graphs of prime order, we show that there are no sequences of real orthonormal bases where all sequences of eigenfunctions equidistribute. To obtain this result, we also prove that, for large 4-regular circulant graphs of prime order, the maximum multiplicity of the eigenvalues of the adjacency matrix is two.
title Circulant graphs as an example of discrete quantum unique ergodicity
topic Mathematical Physics
81Q50, 05C50, 58J51
url https://arxiv.org/abs/2411.09028