Dissipative Phase Transition


We recently probed a dissipative phase transition in zero dimensions by measuring the dynamical  optical hysteresis of a single mode cavity.
Phys. Rev. Lett. 118, 247402 (2017). pdf


For more than 40 years, optical bistability — the existence of two stable states with different photon numbers for one driving condition —has been reported. Remarkably, the quantum theory of a nonlinear resonator always predicts a unique steady-state. This apparent contradiction arises because quantum fluctuations can induce switching between states (leading to a unique steady-state) over astronomical time scales. While fluctuations forbid the static hysteresis associated with bistability, hysteresis emerges dynamically for finite sweep rates of the driving intensity.

Dynamical Optical Hysteresis

Recently ,we demonstrated the influence of quantum fluctuations on the optical hysteresis of photonic microcavities.  For decreasing speeds of the driving power across the “bistability”, the hysteresis area decays following a double power-law. The time scale of the transition from one power law to another can be vastly greater than the photon lifetime. This characteristic time depends on the strength of the photon-photon interactions and on the driving conditions. Approaching the thermodynamic limit of high photon densities, the double power-law becomes a single power-law. This algebraic behavior characterizes a dissipative phase transition.



Critical phenomena in photonic lattices