Intermittency and dynamical Lee-Yang zeros of open quantum systems

Area of Science:

• Quantum physics
• Statistical mechanics
• Complex systems

Background:

• Open quantum systems exhibit complex dynamics, including phase transitions.
• Dynamical observables in these systems can display large-deviation behavior at long times.

Purpose of the Study:

• Investigate phase transitions in open quantum systems using Lee-Yang zeros.
• Analyze the behavior of dynamical free energies and their singularities.
• Understand dynamical intermittency and phase coexistence in quantum trajectories.

Main Methods:

• Utilized high-order cumulants to study Lee-Yang zeros of generating functions.
• Analyzed the long-time large-deviation form of generating functions.
• Examined driven three-level systems and the dissipative Ising model.
• Investigated short-time behavior of dynamical Lee-Yang zeros.

Main Results:

• Identified singularities in cumulant generating functions as phase transitions in dynamical trajectory ensembles.
• Observed dynamical intermittency in quantum jump statistics for both models.
• Determined critical counting field values associated with intermittency and phase coexistence.
• Constructed a trajectory phase diagram for the dissipative Ising model.

Conclusions:

• Dynamical free energy singularities signal phase transitions in open quantum systems.
• Short-time analysis of Lee-Yang zeros provides insights into critical phenomena.
• The dissipative Ising model transitions from ferromagnetic to paramagnetic states at a specific transverse field value.