Entanglement And Cross-Correlations In Cavity QED
Perry R. Rice, Julio R. Gea-Banacloche, M. L. Terraciano, Daniel L. Freimund, Luis A. Orozco · arXiv (Cornell University) · 2006
We investigate entanglement in an open quantum system, specifically a single atom in a driven optical cavity with cavity loss and spontaneous emission. In the weak driving limit, the system reaches a pure state in the steady state. We find that any normalized cross-correlation function, of the type historically considered in quantum optics, is an indicator of the entanglement in a system. In particular we find that the zero delay intensity-field cross correlation is proportional to the entanglement of formation for weak driving fields. Other correlation functions are considered as indicators, or witnesses, of entanglement.