Time evolution of the variance of the field amplitude in cavity QED

Summary form only given. Reconstruction of quantum states of the electromagnetic field has become an important technique in quantum optics. Tomographic algorithms to reconstruct the Wigner function and direct density matrix measurement schemes both provide a full representation of a quantum state. We are interested in the time evolution of a cavity quantum electrodynamic (QED) system that, after a detected quantum fluctuation, regresses back to its steady state in a dynamical way. We would like to follow the evolution of the state in Hilbert space as it returns back to equilibrium. Few systems in quantum optics have time scales where present day digitizing electronics can capture the signals necessary to reconstruct the state evolution. Our cavity QED system does.