Dressed-state approach to population trapping in the Jaynes-Cummings model

The phenomenon of atomic population trapping in the Jaynes-Cummings model i s analysed from a dressed-state point of view. A general condition for the occurrence of partial or total trapping from an arbitrary, pure initial ato m-field state is obtained in the form of a bound to the variation of the at omic inversion. More generally, it is found that in the presence of initial atomic or atom-field coherence the population dynamics is governed not by the field's initial photon distribution, but by a 'weighted dressedness' di stribution characterizing the joint atom-field state. In particular, indivi dual revivals in the inversion can be analytically described to good approx imation in terms of that distribution, even in the limit of large populatio n trapping. This result is obtained through a generalization of the Poisson Summation Formula method for an analytical description of revivals develop ed by Fleischhauer and Schleich (1993, Phys. Rev. A, 47, 4258).