Robustness of quantum chaos and anomalous relaxation in open quantum circuits

Understand

Dissipation is a ubiquitous phenomenon that affects the fate of chaotic quantum many-body dynamics.

• Here, we show that chaos can be robust against dissipation but can also assist and anomalously enhance relaxation.
• We compute exactly the dissipative form factor of a generic Floquet quantum circuit with arbitrary on-site dissipation modeled by quantum channels and find that, for long enough times, the system always relaxes with two distinctive regimes characterized by the presence or absence of gap-closing.
• While the system can sustain a robust ramp for a long (but finite) time interval in the gap-closing regime, relaxation is ``assisted'' by quantum chaos in the regime where the gap remains nonzero.