  A study of "high temperature" entangled states in a system of two
parametrically coupled quantum oscillators placed into independent thermal
baths is performed taking into account partially coherent parametric pump.
Processes in an open system are considered based on the Heisenberg-Langevin
formalism. We obtain a closed system of equations for the averaged quadratic
correlation functions in quantum stochastic problem as a result of Markov
processes approximation. On the basis of numerical calculations the dynamics of
the logarithmic negativity, which is the measure of entanglement in the system,
is investigated. It is shown that the partial coherence of the parametric pump
makes the lifetime of the entangled states finite. The threshold
characteristics of the formation and existence of these states are specified.
