Eigenvalue collisions for periodic matrix families associated with Ginibre matrices

Fuente: arXiv
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Autor principal: Vargas, Carlos
Formato: Preprint
Publicado: 2025
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author Vargas, Carlos
author_facet Vargas, Carlos
contents We study, count and locate the exceptional points where eigenvalues collide for certain families of matrices $$R(s,t) = \cos(s π/ 2)C + \sin(s π/ 2)U(t), \quad s,t \in [0,1]$$ where $C$ is a realization of a Ginibre random matrix, or a closely related matrix, and $U(t)$ is a $t$-periodic diagonal matrix whose eigenvalues move along the unit circle or other parameterized curves (simple or not). To do this, we track eigenvalues continuously along simple curves, searching for eigenvalue discrepancies after looping, indicating such collision-events inside said curves. Although stochastic in nature, the collision count for the circle cases repeatedly yielded $N(N-1)$ under fairly general circumstances, where $N$ is the matrix dimension. More collisions were observed for the elliptic generalization and for other curves. We include a package to compute and visualize these results.
format Preprint
id arxiv_https___arxiv_org_abs_2503_17178
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Eigenvalue collisions for periodic matrix families associated with Ginibre matrices
Vargas, Carlos
Probability
15B52, 60B20
We study, count and locate the exceptional points where eigenvalues collide for certain families of matrices $$R(s,t) = \cos(s π/ 2)C + \sin(s π/ 2)U(t), \quad s,t \in [0,1]$$ where $C$ is a realization of a Ginibre random matrix, or a closely related matrix, and $U(t)$ is a $t$-periodic diagonal matrix whose eigenvalues move along the unit circle or other parameterized curves (simple or not). To do this, we track eigenvalues continuously along simple curves, searching for eigenvalue discrepancies after looping, indicating such collision-events inside said curves. Although stochastic in nature, the collision count for the circle cases repeatedly yielded $N(N-1)$ under fairly general circumstances, where $N$ is the matrix dimension. More collisions were observed for the elliptic generalization and for other curves. We include a package to compute and visualize these results.
title Eigenvalue collisions for periodic matrix families associated with Ginibre matrices
topic Probability
15B52, 60B20
url https://arxiv.org/abs/2503.17178