Quantum phase space distributions in thermofield dynamics

Abstract

It is shown that the quantum phase space distributions corresponding to a density operator ρ can be expressed, in thermofield dynamics, as overlaps between the state |ρ> and `thermal' coherent states. The usefulness of this approach is brought out in the context of a master equation describing a nonlinear oscillator for which exact expressions for the quantum phase distributions for an arbitrary initial condition are derived.