Facilitated spin models of dissipative quantum glasses

TL;DR

This paper introduces dissipative quantum spin models that mimic classical facilitated glasses, exhibiting complex glassy dynamics and quantum dynamic heterogeneity without static order, highlighting quantum fluctuations' role in enhancing glassiness.

Contribution

The paper presents a novel class of quantum facilitated spin models with local interactions, capturing glassy behavior and dynamic heterogeneity in a quantum setting.

Findings

Models show glassy dynamics despite trivial stationary states.

Quantum fluctuations can enhance glassiness near the classical limit.

Presence of quantum dynamic heterogeneity and decoupling of timescales.

Abstract

We introduce a class of dissipative quantum spin models with local interactions and without quenched disorder that show glassy behaviour. These models are the quantum analogs of the classical facilitated spin models. Just like their classical counterparts, quantum facilitated models display complex glassy dynamics despite the fact that their stationary state is essentially trivial. In these systems, dynamical arrest is a consequence of kinetic constraints and not of static ordering. These models display a quantum version of dynamic heterogeneity: the dynamics towards relaxation is spatially correlated despite the absence of static correlations. Associated dynamical fluctuation phenomena such as decoupling of timescales is also observed. Moreover, we find that close to the classical limit quantum fluctuations can enhance glassiness, as recently reported for quantum liquids.