Critical fluctuations of mode-hopping in a confined, driven-dissipative quantum system

We report experimental observation and theoretical modeling of fluctuations in a non-equilibrium Bose-Einstein condensate of polaritons near the phase boundary for onset of condensation. We find a critical fluctuation effect in which the fluctuations have a maximum at the phase boundary. Surprisingly, we see these fluctuations on time scales very long compared to the intrinsic scattering time of the polaritons, indicating that the system has metastable telegraph-type switching between modes. The theoretical modeling reproduces the experimental effects, and indicates that classical noise is not sufficient to explain the experiments; quantum noise must be introduced in the model.