Non-Hermitian expander obtained with Haar distributed unitaries

Fuente: arXiv
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Main Author: Timhadjelt, Sarah
Format: Preprint
Published: 2024
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author Timhadjelt, Sarah
author_facet Timhadjelt, Sarah
contents We consider a random quantum channel obtained by taking a selection of $d$ independent and Haar distributed $N$ dimensional unitaries. We follow the argument of Hastings to bound the spectral gap in terms of eigenvalues and adapt it to give an exact estimate of the spectral gap in terms of singular values \cite{hastings2007random,harrow2007quantum}. This shows that we have constructed a random quantum expander in terms of both singular values and eigenvalues. The lower bound is an analog of the Alon-Boppana bound for $d$-regular graphs. The upper bound is obtained using Schwinger-Dyson equations.
format Preprint
id arxiv_https___arxiv_org_abs_2406_10029
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Non-Hermitian expander obtained with Haar distributed unitaries
Timhadjelt, Sarah
Probability
Mathematical Physics
Quantum Physics
We consider a random quantum channel obtained by taking a selection of $d$ independent and Haar distributed $N$ dimensional unitaries. We follow the argument of Hastings to bound the spectral gap in terms of eigenvalues and adapt it to give an exact estimate of the spectral gap in terms of singular values \cite{hastings2007random,harrow2007quantum}. This shows that we have constructed a random quantum expander in terms of both singular values and eigenvalues. The lower bound is an analog of the Alon-Boppana bound for $d$-regular graphs. The upper bound is obtained using Schwinger-Dyson equations.
title Non-Hermitian expander obtained with Haar distributed unitaries
topic Probability
Mathematical Physics
Quantum Physics
url https://arxiv.org/abs/2406.10029