Universal scaling at a pre-thermal dark state

Marvin Syed, Tilman Enss, Nicolò Defenu

Published 2021-12-28Version 1

Recent experimental and theoretical progress, as well as the prospect of commercially viable quantum technologies have inspired great interest in the study of open quantum systems and their dynamics. Many open quantum systems are well described by an effective non-hermitian Hamiltonian generating a time-evolution that allows eigenstates to decay and dissipate to the environment. In this framework, quantum coherent scaling is traditionally tied to the appearance of dark states, where the effect of dissipation becomes negligible. Here, we discuss the universal dynamical scaling after a sudden quench of the non-hermitian O(N ) model Hamiltonian. While universality is generally spoiled by non-hermiticity, we find that for a given set of internal parameters short-time scaling behaviour is restored with an initial slip exponent profoundly different from that of closed quantum systems. This result is tied to the compensation of dissipation by interaction effects at short times leading to a pre-thermal dark state, where coherent many-body dynamics can be still observed.