Quantum instanton approach to metastable collective spin systems: Numerical implementation and applications
The paper introduces a quantum instanton framework using exact quasiprobability dynamics to describe rare switching between long-lived metastable states in driven-dissipative collective spin systems. This method was numerically implemented and applied to the Lipkin-Meshkov-Glick and cooperative resonance fluorescence models, successfully predicting stationary magnetization, phase transition points, and relaxation rate scaling.