Eigenvalues of tridiagonal Hermitian Toeplitz matrices with perturbations in the off-diagonal corners

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Autori principali: Grudsky, Sergei M., Maximenko, Egor A., Soto-González, Alejandro
Natura: Preprint
Pubblicazione: 2020
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author Grudsky, Sergei M.
Maximenko, Egor A.
Soto-González, Alejandro
author_facet Grudsky, Sergei M.
Maximenko, Egor A.
Soto-González, Alejandro
contents In this paper we study the eigenvalues of Hermitian Toeplitz matrices with the entries $2,-1,0,\ldots,0,-α$ in the first column. Notice that the generating symbol depends on the order $n$ of the matrix. If $|α|\le 1$, then the eigenvalues belong to $[0,4]$ and are asymptotically distributed as the function $g(x)=4\sin^2(x/2)$ on $[0,π]$. The situation changes drastically when $|α|>1$ and $n$ tends to infinity. Then the two extreme eigenvalues (the minimal and the maximal one) lay out of $[0,4]$ and converge rapidly to certain limits determined by the value of $α$, whilst all others belong to $[0,4]$ and are asymptotically distributed as $g$. In all cases, we transform the characteristic equation to a form convenient to solve by numerical methods, and derive asymptotic formulas for the eigenvalues.
format Preprint
id arxiv_https___arxiv_org_abs_2009_01401
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle Eigenvalues of tridiagonal Hermitian Toeplitz matrices with perturbations in the off-diagonal corners
Grudsky, Sergei M.
Maximenko, Egor A.
Soto-González, Alejandro
Functional Analysis
Spectral Theory
(2010): 15B05, 15A18, 41A60, 65F15, 47A55
In this paper we study the eigenvalues of Hermitian Toeplitz matrices with the entries $2,-1,0,\ldots,0,-α$ in the first column. Notice that the generating symbol depends on the order $n$ of the matrix. If $|α|\le 1$, then the eigenvalues belong to $[0,4]$ and are asymptotically distributed as the function $g(x)=4\sin^2(x/2)$ on $[0,π]$. The situation changes drastically when $|α|>1$ and $n$ tends to infinity. Then the two extreme eigenvalues (the minimal and the maximal one) lay out of $[0,4]$ and converge rapidly to certain limits determined by the value of $α$, whilst all others belong to $[0,4]$ and are asymptotically distributed as $g$. In all cases, we transform the characteristic equation to a form convenient to solve by numerical methods, and derive asymptotic formulas for the eigenvalues.
title Eigenvalues of tridiagonal Hermitian Toeplitz matrices with perturbations in the off-diagonal corners
topic Functional Analysis
Spectral Theory
(2010): 15B05, 15A18, 41A60, 65F15, 47A55
url https://arxiv.org/abs/2009.01401