Buijsman W, Gritsev V, Sprik R. Nonergodicity in the Anisotropic Dicke Model.
PHYSICAL REVIEW LETTERS 2017;
118:080601. [PMID:
28282152 DOI:
10.1103/physrevlett.118.080601]
[Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Indexed: 06/06/2023]
Abstract
We study the ergodic-nonergodic transition in a generalized Dicke model with independent corotating and counterrotating light-matter coupling terms. By studying level statistics, the average ratio of consecutive level spacings, and the quantum butterfly effect (out-of-time correlation) as a dynamical probe, we show that the ergodic-nonergodic transition in the Dicke model is a consequence of the proximity to the integrable limit of the model when one of the couplings is set to zero. This can be interpreted as a hint for the existence of a quantum analogue of the classical Kolmogorov-Arnold-Moser theorem. In addition, we show that there is no intrinsic relation between the ergodic-nonergodic transition and the precursors of the normal-superradiant quantum phase transition.
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