Dual squeezed states in an atom-photon cluster and their manifestations

摘要

The general kinetic equation for an isolated two-level atom and a high-Q cavity mode in a heat bath exhibiting quantum correlations (entangled bath) is applied to the analysis of the squeezed states of the collective system. Two types of collective operators are introduced for the analysis: one is based on bosonic commutation relations, and the other, on the commutation relations of the algebra obtained by a polynomial deformation of the angular momentum algebra. On the basis of these relations, formulas for observables are constructed that identify squeezed states in the system. It is shown that, under certain conditions, the collec- tive system exhibits dual squeezing within the relations for boson operators, as well as for the operators con- structed from the angular momentum algebra. Such squeezing is demonstrated under a projective measure- ment of an atom and for an entanglement swapping protocol. In the latter case, when measuring two initially independent atomic systems, depending on the type of measurement, two cavity modes collapse into a non- separable state, which is described either by a nonseparability relation based on boson operators or by a rela- tion based on the operators of the algebra of the quasimomentum of the collective system consisting of these two modes.