2020/05/21 by Chao Yin, Pai Peng, Xiaoyang Huang +2
Mathematics · Physics and Astronomy · #Classical mechanics #Floquet theory #Hamiltonian (control theory) #Limit (mathematics) #Mathematical analysis #Mathematical optimization #Mathematics #Observable #Physics #Quantum #Quantum many-body systems #Quantum mechanics #Quantum, superfluid, helium dynamics #Spectroscopy and Quantum Chemical Studies #Statistical physics #cond-mat.stat-mech #cond-mat.str-el #quant-ph
paper · pdf · doi:10.1103/physrevb.103.054305
published as Phys. Rev. B 103, 054305 (2021) · 12 pages, 9 figures. arXiv admin note: substantial text overlap with arXiv:1912.05799
arxiv created 2020/05/21 · openalex publication_date 2021/02/15 · arxiv updated 2021/02/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
Prethermalization, by introducing emergent quasiconserved observables, plays a crucial role in protecting periodically driven (Floquet) many-body phases over an exponentially long time, while the ultimate fate of such quasiconserved operators can signal thermalization to infinite temperature. To elucidate the properties of prethermal quasiconservation in many-body Floquet systems, here we systematically analyze infinite-temperature correlations between observables. We numerically show that the late-time behavior of the autocorrelations unambiguously distinguishes quasiconserved observables from nonconserved ones, allowing one to single out a set of linearly independent quasiconserved observables. By investigating two Floquet spin models, we identify two different mechanisms underlying the quasiconservation law. First, we numerically verify energy quasiconservation when the driving frequency is large, so that the system dynamics is approximately described by a static prethermal Hamiltonian. More interestingly, under moderate driving frequency, another quasiconserved observable can still persist if the Floquet driving contains a large global rotation. We show theoretically how to calculate this conserved observable and provide numerical verification. Having systematically identified all quasiconserved observables, we can finally investigate their behavior in the infinite-time limit and thermodynamic limit, using autocorrelations obtained from both numerical simulation and experiments in solid-state nuclear magnetic resonance systems.