New features of the fluorescence spectra in the driven Jaynes-Cummings system

We investigate the fluorescence spectra of a Jaynes-Cummings system where t he cavity is driven by an external coherent field. For a strong driving-fie ld, it is observed that the vacuum Rabi-splitted peaks are displaced from t he usual locations of omega = omega (0) +/- g to omega = omega (0) +/- g[1 - (2 epsilon /g)(2)](3/4) due to the dynamic Stark shift, where omega (0) i s the atomic transition frequency, g, the atom-cavity coupling constant, an d epsilon, the driving-field amplitude. Furthermore, a number of additional peaks arising from transitions between non-adjacent dressed levels are als o obtained. The origins of these are purely dynamical in the sense that the y are caused by the finite strength of the external field.