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Collapse and revival of quantum many-body scars via Floquet engineering

Mukherjee, B and Nandy, S and Sen, A and Sen, D and Sengupta, K (2020) Collapse and revival of quantum many-body scars via Floquet engineering. In: Physical Review B, 101 (24).

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Official URL: https://dx.doi.org/10.1103/PhysRevB.101.245107


The presence of quantum scars, athermal eigenstates of a many-body Hamiltonian with finite-energy density, leads to an absence of ergodicity and long-time coherent dynamics starting from initial states that have a high overlap with scars as experimentally observed in a chain of ultracold Rydberg atoms. We show, via study of a periodically driven Rydberg chain, that the drive frequency acts as a tuning parameter for several reentrant transitions between ergodic and weak ergodicity breaking regimes. The former regime shows rapid thermalization of correlation functions and absence of scars in the Floquet spectrum of the system. The latter regime, in contrast, has scars; they lead to long-time coherent dynamics of correlation functions. We provide an analytical explanation of the existence of these regimes by going beyond a high-frequency Magnus expansion and using a novel perturbative approach valid at large drive amplitudes to derive a Floquet Hamiltonian which qualitatively explains the behavior of the driven system at arbitrary frequencies. We also discuss experiments involving finite Rydberg chains which can validate our theory. Our results demonstrate the possibility of drive-frequency-induced tuning between ergodic and weak ergodicity breaking dynamics in a disorder-free quantum many-body system. © 2020 American Physical Society.

Item Type: Journal Article
Publication: Physical Review B
Publisher: American Physical Society
Additional Information: Copy right for this article belongs to American Physical Society
Keywords: Dynamics; Quantum theory, Arbitrary frequencies; Coherent dynamics; Collapse and revival; Correlation function; Floquet Hamiltonian; Perturbative approach; Quantum many-body systems; Ultracold Rydberg atoms, Hamiltonians
Department/Centre: Division of Physical & Mathematical Sciences > Centre for High Energy Physics
Date Deposited: 20 Nov 2020 09:08
Last Modified: 20 Nov 2020 09:08
URI: http://eprints.iisc.ac.in/id/eprint/65973

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