Singularities in large deviations of work in quantum quenches

TL;DR

This paper studies the large deviations of work in a quantum quench across a critical point, revealing a new out-of-equilibrium phase transition indicated by a non-analytical rate function in the work distribution.

Contribution

It identifies a novel regime in large deviations of work where the rate function shows a non-analytical point, suggesting an out-of-equilibrium phase transition.

Findings

Discovered a non-analytical point in the rate function of work distribution.

Provided evidence for an out-of-equilibrium phase transition in quantum quenches.

Extended classification schemes of large deviations in quantum systems.

Abstract

We investigate large deviations of the work performed in a quantum quench across two different phases separated by a quantum critical point, using as example the Dicke model quenched from its superradiant to its normal phase. We extract the distribution of the work from the Loschmidt amplitude and compute for both the corresponding large-deviation forms. Comparing these findings with the predictions of the classification scheme put forward in [Phys. Rev. Lett. 109, 250602 (2012)], we are able to identify a regime which is in fact distinct to the ones identified so far: here the rate function exhibits a non-analytical point which is a strong indication of the existence of an out-of-equilibrium phase transition in the rare fluctuations of the work.