Dissipation-driven quantum phase transitions in collective spin systems

Abstract

We consider two different collective spin systems subjected to strong dissipation -- on the same scale as interaction strengths and external fields -- and show that either continuous or discontinuous dissipative quantum phase transitions can occur as the dissipation strength is varied. First, we consider a well known model of cooperative resonance fluorescence that can exhibit a second-order quantum phase transition, and analyze the entanglement properties near the critical point. Next, we examine a dissipative version of the Lipkin-Meshkov-Glick interacting collective spin model, where we find that either first- or second-order quantum phase transitions can occur, depending only on the ratio of the interaction and external field parameters. We give detailed results and interpretation for the steady state entanglement in the vicinity of the critical point, where it reaches a maximum. For the first-order transition we find that the semiclassical steady states exhibit a region of bistability.

12 pages, 16 figures, removed section on homodyne spectra

References in corpus (4)

• Phase diagram and critical exponents of a dissipative Ising spin chain in a transverse magnetic field
• Collective spin systems in dispersive optical cavity QED: Quantum phase transitions and entanglement
• First-order super-radiant phase transitions in a multi-qubit--cavity system
• Dissipation-driven phase transition in 2D Josephson arrays