Metastability in open quantum systems

Metastability is a large separation in timescales of system dynamics, which manifests itself in the existence of a time regime when states of the system appear stationary, before the eventual relaxation towards a true stationary state occurring at much later times. In this talk, I will focus on the emergence of classical metastability in open quantum systems [1], i.e., the case when metastable states can be approximated as probabilistic mixtures of a finite number of states. I will show that a number of classical features follow from this approximation. First, metastable states are mixtures of approximately disjoint states that can be distinguished with negligible error and thus play the role of metastable phases. Second, symmetries of the dynamics correspond to approximate permutations of metastable phases and thus are necessarily discrete. Third, the long-time dynamics – the final relaxation towards the stationary state – is approximated by classical stochastic dynamics between the metastable phases. These results will be illustrated with the example of an open quantum East model [2], which features complex relaxation despite the absence of phase transitions in its stationary state.

[1] arXiv:2006.01227

[2] arXiv:2010.15304

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Meeting ID: 812 2113 8021

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