Fock-space delocalization and the emergence of the Porter-Thomas distribution from dual-unitary dynamics

Fuente: arXiv
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Autores principales: Claeys, Pieter W., De Tomasi, Giuseppe
Formato: Preprint
Publicado: 2024
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author Claeys, Pieter W.
De Tomasi, Giuseppe
author_facet Claeys, Pieter W.
De Tomasi, Giuseppe
contents The chaotic dynamics of quantum many-body systems are expected to quickly randomize any structured initial state, delocalizing it in Fock space. In this work, we study the spreading of an initial product state in Hilbert space under dual-unitary dynamics, captured by the inverse participation ratios and the distribution of overlaps (bit-string probabilities). We consider the self-dual kicked Ising model, a minimal model of many-body quantum chaos which can be seen as either a periodically driven Floquet model or a dual-unitary quantum circuit. Both analytically and numerically, we show that the inverse participation ratios rapidly approach their ergodic values, corresponding to those of Haar random states, and establish the emergence of the Porter-Thomas distribution for the overlap distribution. Importantly, this convergence happens exponentially fast in time, with a time scale that is independent of system size. We inspect the effect of local perturbations that break dual-unitarity and show a slowdown of the spreading in Fock space, indicating that dual-unitary circuits are maximally efficient at preparing random states.
format Preprint
id arxiv_https___arxiv_org_abs_2408_02732
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Fock-space delocalization and the emergence of the Porter-Thomas distribution from dual-unitary dynamics
Claeys, Pieter W.
De Tomasi, Giuseppe
Quantum Physics
Statistical Mechanics
Chaotic Dynamics
The chaotic dynamics of quantum many-body systems are expected to quickly randomize any structured initial state, delocalizing it in Fock space. In this work, we study the spreading of an initial product state in Hilbert space under dual-unitary dynamics, captured by the inverse participation ratios and the distribution of overlaps (bit-string probabilities). We consider the self-dual kicked Ising model, a minimal model of many-body quantum chaos which can be seen as either a periodically driven Floquet model or a dual-unitary quantum circuit. Both analytically and numerically, we show that the inverse participation ratios rapidly approach their ergodic values, corresponding to those of Haar random states, and establish the emergence of the Porter-Thomas distribution for the overlap distribution. Importantly, this convergence happens exponentially fast in time, with a time scale that is independent of system size. We inspect the effect of local perturbations that break dual-unitarity and show a slowdown of the spreading in Fock space, indicating that dual-unitary circuits are maximally efficient at preparing random states.
title Fock-space delocalization and the emergence of the Porter-Thomas distribution from dual-unitary dynamics
topic Quantum Physics
Statistical Mechanics
Chaotic Dynamics
url https://arxiv.org/abs/2408.02732