Photon-number parity oscillations in the resonant Jaynes–Cummings model

•For the case of the resonant Jaynes–Cummings model with the field prepared in a large amplitude coherent state, we study the time evolution of the photon-number parity operator.•We show that this quantity, not previously examined, undergoes Rabi-like oscillations that collapse and revive.•We further show that the photon-number parity oscillations occur during the period of quiescence of the atomic inversion.•We examine the total parity of the model and show why the Rabi oscillations of the atomic inversion and of the photon number parity cannot occur simultaneously.

We study the time evolution of photon number parity operator for a single-mode quantized cavity field interacting with a two-level atom as described by the resonant Jaynes–Cummings model. With the field prepared in a coherent state and the atom prepared in its excited state, we find that the photon number parity undergoes oscillations at the Rabi frequency but only during the period between the collapse and revival of the Rabi oscillations of the atomic inversion. We explain this in terms of the global parity of the Jaynes–Cummings model. The phenomenon is related to the interference of the counter-rotating components of the field in phase space, which in turn gives rise to occurrence of highly oscillatory photon number probability distributions near half the revival time of the atomic inversion noted by Bužek et al. (Phys. Rev. A 45, 1992, p. 8190). Detection of the photon number oscillations would amount to a detection of this interference effect.