Decoherence of quantum excitation of even/odd coherent states in thermal environment

Abstract

In this paper, we study the decoherence of quantum excitation (photon-added) even /odd coherent states, $((\hat a{^{\dagger }})^{m} \left | {\alpha _ \pm } \right \rangle )$ , in a thermal environment by investigating the variation of negative part of the Wigner quasidistribution function vs. the rescaled time. For this purpose, at first we obtain the time-dependent Wigner function corresponding to the mentioned states in the framework of standard master equation. Then, the time evolution of the Wigner function associated with photon-added even /odd coherent states, as well as the number of added photons m are analysed. It is shown that, in both states, the negative part of the Wigner function decreases with time. By deriving the threshold value of the rescaled time for single photon-added even /odd coherent states, it is also found that, if the rescaled time exceeds the threshold value, the associated Wigner function becomes positive, i.e., the decoherence occurs completely.