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arXiv · 1610.06751

Non-ergodicity in the Anisotropic Dicke model

Wouter Buijsman·Vladimir Gritsev·Rudolf Sprik
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Abstract

We study the ergodic -- non-ergodic transition in a generalized Dicke model with independent co- and counter rotating 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 -- non-ergodic 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. Besides, we show that there is no intrinsic relation between the ergodic -- non-ergodic transition and the precursors of the normal -- superradiant quantum phase transition.

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Wouter Buijsman, Vladimir Gritsev, Rudolf Sprik. 2017-01-25. Non-ergodicity in the Anisotropic Dicke model. https://doi.org/10.1103/physrevlett.118.080601

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