Phenomenological-operator approach to dissipation in cavity quantum electrodynamics

Abstract

We present a phenomenological-operator approach to describe energy dissipation in cavity QED phenomena. This approach, developed for an absolute-zero and a thermal environment, considerably simplifies the introduction of the inevitable errors due to the environmental degrees of freedom when describing processes involving dispersive atom-field interactions. The main result in the present work consists in furnishing a straightforward technique to estimate the fidelity resulting from dispersive atom-field interactions, precluding the necessity of performing the usually extensive ab initio calculations. Furthermore, we expect that the present work can help us account for dissipation in resonant atom-field interactions and even help us achieve a general phenomenological approach to estimate the effects of dissipation in whichever system. To illustrate the universal applicability of the present technique, we calculate the fidelity of a mesoscopic quantum superposition state engineered in a lossy cavity, considering also the excited-state spontaneous decay of the required atom. For the case of a stable atomic excited state, the fidelity computed here is in agreement with a recently announced exact calculation.