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arXiv · 1503.04672

The Open-System Dicke-Model Quantum Phase Transition with a Sub-Ohmic Bath

D. Nagy·P. Domokos
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Abstract

We show that the critical exponent of a quantum phase transition in a damped-driven open system is determined by the spectral density function of the reservoir. We consider the open-system variant of the Dicke model, where the driven boson mode and also the large N-spin couple to independent reservoirs at zero temperature. The critical exponent, which is $1$ if there is no spin-bath coupling, decreases below 1 when the spin couples to a sub-Ohmic reservoir.

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D. Nagy, P. Domokos. 2015-03-16. The Open-System Dicke-Model Quantum Phase Transition with a Sub-Ohmic Bath. https://doi.org/10.1103/physrevlett.115.043601

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