Rabi oscillations and macroscopic quantum superposition states

Abstract

A two-level atom interacting with a single radiation mode is considered, without the rotating-wave approximation, in the strong coupling regime. It is shown that, in agreement with the recent results on Rabi oscillations in a Josephson junction (Y. Nakamura, Yu. A. Pashkin and J. S. Tsai, Phys. Rev. Lett. {\bf 87}, 246601 (2001)), the Rabi frequency is indeed proportional to first kind integer order Bessel functions in the limit of a large number of photons and the dressed states are macroscopic quantum superposition states. To approach this problem analytically use is made of the dual Dyson series and the rotating-wave approximation.Comment: 7 pages, revtex, no figures. I have to thank Kazuyuki Fujii for pointing me out some corrections to introduce into the paper. Besides, the title and the nomenclature has been changed in agreement to editorial requirements. Finally, the correct citation for the paper by Nakamura et al. has been introduce