Dip-ramp-plateau for Dyson Brownian motion from the identity on $U(N)$

Fuente: arXiv
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Auteurs principaux: Forrester, Peter J., Kieburg, Mario, Li, Shi-Hao, Zhang, Jiyuan
Format: Preprint
Publié: 2022
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author Forrester, Peter J.
Kieburg, Mario
Li, Shi-Hao
Zhang, Jiyuan
author_facet Forrester, Peter J.
Kieburg, Mario
Li, Shi-Hao
Zhang, Jiyuan
contents In a recent work the present authors have shown that the eigenvalue probability density function for Dyson Brownian motion from the identity on $U(N)$ is an example of a newly identified class of random unitary matrices called cyclic Pólya ensembles. In general the latter exhibit a structured form of the correlation kernel. Specialising to the case of Dyson Brownian motion from the identity on $U(N)$ allows the moments of the spectral density, and the spectral form factor $S_N(k;t)$, to be evaluated explicitly in terms of a certain hypergeometric polynomial. Upon transformation, this can be identified in terms of a Jacobi polynomial with parameters $(N(μ- 1),1)$, where $μ= k/N$ and $k$ is the integer labelling the Fourier coefficients. From existing results in the literature for the asymptotics of the latter, the asymptotic forms of the moments of the spectral density can be specified, as can $\lim_{N \to \infty} {1 \over N} S_N(k;t) |_{μ= k/N}$. These in turn allow us to give a quantitative description of the large $N$ behaviour of the average $ \langle | \sum_{l=1}^N e^{ i k x_l} |^2 \rangle$. The latter exhibits a dip-ramp-plateau effect, which is attracting recent interest from the viewpoints of many body quantum chaos, and the scrambling of information in black holes.
format Preprint
id arxiv_https___arxiv_org_abs_2206_14950
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Dip-ramp-plateau for Dyson Brownian motion from the identity on $U(N)$
Forrester, Peter J.
Kieburg, Mario
Li, Shi-Hao
Zhang, Jiyuan
Mathematical Physics
In a recent work the present authors have shown that the eigenvalue probability density function for Dyson Brownian motion from the identity on $U(N)$ is an example of a newly identified class of random unitary matrices called cyclic Pólya ensembles. In general the latter exhibit a structured form of the correlation kernel. Specialising to the case of Dyson Brownian motion from the identity on $U(N)$ allows the moments of the spectral density, and the spectral form factor $S_N(k;t)$, to be evaluated explicitly in terms of a certain hypergeometric polynomial. Upon transformation, this can be identified in terms of a Jacobi polynomial with parameters $(N(μ- 1),1)$, where $μ= k/N$ and $k$ is the integer labelling the Fourier coefficients. From existing results in the literature for the asymptotics of the latter, the asymptotic forms of the moments of the spectral density can be specified, as can $\lim_{N \to \infty} {1 \over N} S_N(k;t) |_{μ= k/N}$. These in turn allow us to give a quantitative description of the large $N$ behaviour of the average $ \langle | \sum_{l=1}^N e^{ i k x_l} |^2 \rangle$. The latter exhibits a dip-ramp-plateau effect, which is attracting recent interest from the viewpoints of many body quantum chaos, and the scrambling of information in black holes.
title Dip-ramp-plateau for Dyson Brownian motion from the identity on $U(N)$
topic Mathematical Physics
url https://arxiv.org/abs/2206.14950