Time-resolved observation of a dynamical phase transition of atoms in a cavity

TL;DR

This paper reports on a time-resolved experimental observation of a dynamical phase transition in a laser-driven atomic cavity system, revealing how the system switches from a blockade to a transparent phase with critical fluctuations.

Contribution

It provides the first direct time-resolved measurement of the dynamical phase transition in a cavity QED system, highlighting the critical behavior and fluctuation enhancement.

Findings

Observation of a transition from blockade to transparent phase

Quantification of fluctuations near the critical point

Time-resolved dynamics of the phase transition

Abstract

The transparence of a laser-driven optical resonator containing an ensemble of cold atoms can have two distinct, robust states. Atoms in their initially prepared pure state blockade the transmission by detuning the cavity mode from the laser drive. The interacting system can, however, transition into an uncoupled state via a non-linear channel opening up in a critical run-away process toward a transparent bright phase. The experiment enables a time-resolved observation of the dynamical transmission blockade breakdown phase transition as well as quantification of enhanced fluctuations in the critical region.