Dissipation-Induced Anomalous Multicritical Phenomena

Area of Science:

• Quantum optics
• Condensed matter theory
• Quantum information science

Background:

• Driven-dissipative systems with two-level atoms interacting with cavity modes exhibit complex phase transitions.
• Closed systems display multiple phase transitions, culminating in a multicritical point.

Purpose of the Study:

• To investigate the impact of dissipation on a paradigmatic driven-dissipative model.
• To analyze the alteration of phase diagrams and critical points due to dissipation.

Main Methods:

• Theoretical exploration of a driven-dissipative model.
• Analysis of symmetry breaking in both closed and open systems.
• Quantum fluctuation analysis to characterize critical points.

Main Results:

• Infinitesimal dissipation erases phases with broken continuous symmetry.
• The multicritical point becomes brittle and splits into two tricritical points.
• These tricritical points exhibit anomalous finite fluctuations, differing from standard systems.

Conclusions:

• Dissipation fundamentally reshapes the phase diagram of driven-dissipative systems.
• The identified tricritical points represent a novel phenomenon in quantum critical phenomena.
• Findings have implications for quantum cavities, circuit QED, and optomechanics.