Quantum feedback in cavity quantum electrodynamics

Photon correlation measurements reveal the response of the conditional evolution of the cavity QED system to a novel quantum feedback protocol. A photodetection collapses the state of the system and triggers a feedback pulse with an adjustable delay and amplitude that alters the intensity driving the system. The system's conditional evolution freezes into a new steady state where it resides until, after an amount of time determined by the experimenter, it re-equilibrates into the original steady state. I carry out a sensitivity analysis using a theoretical model and make quantitative comparisons with measured results. The analysis includes sensitivity response to the amplitude and delay time feedback parameters and the response to off-resonant excitation.