Exceptional Stationary State in a Dephasing Many-Body Open Quantum System
Date: 10 APRIL 2025 from 14:00 to 15:00
Event location: Sala IR-2A
The late-time dynamics of many-body systems is one of the central problems in statistical mechanics. The eventual emergence of Gibbs ensembles at late times for closed systems is usually explained using the Eigenstate Thermalization Hypothesis (ETH): it postulates, among other things, local indistinguishability of the energy eigenstates and proper statistical ensembles. Rare eigenstates that violate ETH are known as many-body scars and can affect the dynamics of the system in a non-trivial way.We investigate a related mechanism for an open quantum many-body system. In particular, we focus on a model that hosts, together with the infinite-temperature state, another additional stationary state. The latter is exceptional in many respects and plays the role of a quantum scar. We discuss the properties of the model, focusing on the fate of interfaces between the two states. We find that at late times an effective description is based on stochastic fluctuations of the interface; in particular, the scar is progressively eroded at a finite velocity, and the interface broadens diffusively. While this mechanism resembles hydrodynamics of local conserved charges, important differences are pointed out.This is a joint work with Alice Marché, Gianluca Morettini, Leonardo Mazza, and Lorenzo Gotta.
Ref. [arxiv:2412.13820].