Discrete Time-Crystalline Order in Cavity and Circuit QED Systems

TL;DR

This paper explores the emergence of discrete time-crystalline order in driven-dissipative cavity and circuit QED systems, revealing rich dynamical phases and transient behaviors through semiclassical and quantum analyses.

Contribution

It introduces a phenomenological framework for dissipative discrete time crystals in Floquet open systems, extending Landau theory to this out-of-equilibrium context.

Findings

Rich dynamical phases in semiclassical limit

Transient discrete time-crystalline signatures in few-qubit regimes

Generalization of Landau theory for Floquet open systems

Abstract

Discrete time crystals are a recently proposed and experimentally observed out-of-equilibrium dynamical phase of Floquet systems, where the stroboscopic evolution of a local observable repeats itself at an integer multiple of the driving period. We address this issue in a driven-dissipative setup, focusing on the modulated open Dicke model, which can be implemented by cavity or circuit QED systems. In the thermodynamic limit, we employ semiclassical approaches and find rich dynamical phases on top of the discrete time-crystalline order. In a deep quantum regime with few qubits, we find clear signatures of a transient discrete time-crystalline behavior, which is absent in the isolated counterpart. We establish a phenomenology of dissipative discrete time crystals by generalizing the Landau theory of phase transitions to Floquet open systems.