Evolution of the coherent state via a new time evolution operator

Abstract

Inspired by the dynamical Casimir effect, we construct a new time evolution operator (NTEO). We study the time evolution of the coherent state (TECS) via the NTEO by the technique of integration within an ordered product (IWOP) of operators. We investigate the quantum statistical properties of it, both analytically and numerically, by evaluating its Q-function, second-order correlation function, photon-number distribution and Wigner function. Furthermore, the fidelity between the TECS and the classical coherent state is also given. It is interesting to find that smaller modulation depth can lead to more chance of sub-Poissonian statistics in some cases. It is also shown that the new time evolution operator not only has squeezing effect, but also has rotating effect.