Squeezed Vacuum as an Accelerator of Revivals

Abstract

In the Dicke model (DM) of a system of A two-level atoms coupled in a high-Q cavity to a single-mode radiation field the total number of excitations N (the number of photons n plus the number of excited atoms) is an integral of motion. There are two limits when the model has an approximately equidistant eigenvalues spectrum: N 《 A (“weak-field” limit) and N 》 A (“strong-field” limit). The atomic inversion response to a photon number state is then truly periodic. According to the above distinction the Jaynes-Cummings model (JCM) belongs to the “strong-field” limit. For an initial field state being a superposition of photon number states the atomic inversion response is a sum of the responses to each of these states weighted with a corresponding photon number distribution P n. If the initial field is in a thermal or squeezed vacuum state the summation over the photon number always includes the region of small n’s with the greatest weights.