Two-step relaxation in local many-body Floquet systems

Žnidarič, Marko (author)

We want to understand how relaxation process from an initial non-generic state proceeds towards a long-time typical state reached under unitary quantum evolution. One would expect that after some initial correlation time relaxation will be a simple exponential decay with constant decay rate. We show that this is not necessarily the case. Studying various Floquet systems with fixed two-qubit gates, and focusing on purity and out-of-time-ordered correlation functions, we find that in many situations relaxation proceeds in two phases of exponential decay having different relaxation rates. Namely, in the thermodynamic limit the relaxation rate exhibits a change at a critical time proportional to system's size. The initial thermodynamically relevant rate can be slower or faster than the asymptotic one, demonstrating that the recently discovered phantom relaxation, in which the decay is slower than predicted by a nonzero transfer matrix gap, is not limited to only random circuits.

• Language: English
• Keywords: statistical physics, quantum mechanics, Floquet systems, complexity dynamics
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FMF - Faculty of Mathematics and Physics
• Publication version: Version of Record
• Publication date: 09.10.2023
• Year: 2023
• Number of pages: 14 str.
• Numbering: Vol. 56, no. 43, art. no. 434001
• PID: 20.500.12556/RUL-155001
• UDC: 536.93
• ISSN on article: 1751-8113
• DOI: 10.1088/1751-8121/acfc05
• COBISS.SI-ID: 188707331
• Publication date in RUL: 13.03.2024

Record is a part of a journal

• Title: Journal of physics : Mathematical and theoretical
• Shortened title: J. phys., A, Math. theor.
• Publisher: IOP Publishing
• ISSN: 1751-8113
• COBISS.SI-ID: 3692314

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: statistična fizika, kvantna mehanika

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: J1-4385
• Name: Kvantna večdelčna fizika in nehermitskost

• Funder: ARRS - Slovenian Research Agency
• Project number: P1-0402
• Name: Matematična fizika