Autofeedback scheme for Schrodinger cat preservation in microwave cavities

We propose a feedback scheme for limiting in a significant way the decohere nce of a linear superposition of two coherent states with opposite phases i n a high-Q microwave cavity. It is based on the injection of appropriately prepared "probe" and "feedback" Rydberg atoms, and greatly improves the mod el presented in [D. Vitali et al., Phys. Rev. Lett. 79, 2442 (1997)]. In th e present scheme, the information transmission between the probe and the fe edback atom is directly mediated by a second auxiliary cavity, making the d etection efficiency for the probe atom no longer a critical parameter. The decoherence time of the superposition state can be significantly increased using presently available technology.