Genuine Bistability in Open Quantum Many-Body Systems

TL;DR

This paper investigates the long-term behavior of open quantum many-body systems, revealing that genuine bistability is limited to specific conditions in some models but persists broadly in others with broken detailed balance.

Contribution

It demonstrates that genuine bistability in open quantum systems is model-dependent, showing limited bistability in the dissipative Ising model and extended bistability in a majority-voter model with three-body interactions.

Findings

Genuine bistability occurs only at a singular point in the dissipative Ising model.

Extended bistability is observed in the majority-voter model with three-body interactions.

Bistability persists even with quantum fluctuations in the majority-voter model.

Abstract

We analyze the long-time evolution of open quantum many-body systems using a variational approach. For the dissipative Ising model, where mean-field theory predicts a wide region of bistable behavior, we find genuine bistability only at a singular point, confirming the previously suggested picture of a first order transition. The situation is dramatically different when considering a majority-voter model including three-body interactions, where we find bistable behavior in an extended region, owing to the breaking of detailed balance in the the effective description of the system. In this model, genuine bistability persists even when quantum fluctuations are added.