On the Lyapunov exponent for the random field Ising transfer matrix, in the critical case

Fuente: arXiv
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Auteurs principaux: Collin, Orphée, Giacomin, Giambattista, Greenblatt, Rafael L., Hu, Yueyun
Format: Preprint
Publié: 2025
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author Collin, Orphée
Giacomin, Giambattista
Greenblatt, Rafael L.
Hu, Yueyun
author_facet Collin, Orphée
Giacomin, Giambattista
Greenblatt, Rafael L.
Hu, Yueyun
contents We study the top Lyapunov exponent of a product of random $2 \times 2$ matrices appearing in the analysis of several statistical mechanical models with disorder, extending a previous treatment of the critical case (Giacomin and Greenblatt, ALEA 19 (2022), 701-728) by significantly weakening the assumptions on the disorder distribution. The argument we give completely revisits and improves the previous proof. As a key novelty we build a probability that is close to the Furstenberg probability, i.e. the invariant probability of the Markov chain corresponding to the evolution of the direction of a vector in ${\mathbb R}^2$ under the action of the random matrices, in terms of the ladder times of a centered random walk which is directly related to the random matrix sequence. We then show that sharp estimates on the ladder times (renewal) process lead to a sharp control on the probability measure we build and, in turn, to the control of its distance from the Furstenberg probability.
format Preprint
id arxiv_https___arxiv_org_abs_2501_08797
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On the Lyapunov exponent for the random field Ising transfer matrix, in the critical case
Collin, Orphée
Giacomin, Giambattista
Greenblatt, Rafael L.
Hu, Yueyun
Probability
Mathematical Physics
60K37, 82B44, 60K35, 37H15
We study the top Lyapunov exponent of a product of random $2 \times 2$ matrices appearing in the analysis of several statistical mechanical models with disorder, extending a previous treatment of the critical case (Giacomin and Greenblatt, ALEA 19 (2022), 701-728) by significantly weakening the assumptions on the disorder distribution. The argument we give completely revisits and improves the previous proof. As a key novelty we build a probability that is close to the Furstenberg probability, i.e. the invariant probability of the Markov chain corresponding to the evolution of the direction of a vector in ${\mathbb R}^2$ under the action of the random matrices, in terms of the ladder times of a centered random walk which is directly related to the random matrix sequence. We then show that sharp estimates on the ladder times (renewal) process lead to a sharp control on the probability measure we build and, in turn, to the control of its distance from the Furstenberg probability.
title On the Lyapunov exponent for the random field Ising transfer matrix, in the critical case
topic Probability
Mathematical Physics
60K37, 82B44, 60K35, 37H15
url https://arxiv.org/abs/2501.08797