Theory of Metastability in Discrete-Time Open Quantum Dynamics

Metastability in open system dynamics describes the phenomena of initial relaxation to longlived metastable states before decaying to the asymptotic stable states. It has been predicted in continuous-time stochastic dynamics of both classical and quantum systems. Here we present a general theory of metastability in discrete-time open quantum dynamics, described by sequential quantum channels. We focus on a general class of quantum channels on a target system, induced by an ancilla system with a pure-dephasing coupling to the target system and under Ramsey sequences. Interesting metastable behaviors are predicted and numerically demonstrated by decomposing the average dynamics into stochastic trajectories. Examples and applications are also discussed.
Comment: 7 pages, 2 figures (+9 pages, 5 figures supplement)