Entanglement behaviors of two-mode squeezed thermal states in two different environments

Abstract

We study entanglement properties of two-mode squeezed thermal states subjected to two sources of decoherence: the common reservoirs and the bosonic memory Gaussian channel. For the former one, we find that there exist three different behaviors: no-sudden death, sudden death, and no-creation of entanglement. The range of parameters characterizing these processes is obtained. For the latter one, we obtain a threshold in the degree of squeezing above which the input states remain always entangled. Otherwise, no entanglement is allowed in bosonic Gaussian channel with memory effect. We show that a degree of memory for quantum channel can be help to increase the initial entanglement, while the mean number of added thermal photons is to fasten the decoherence process.