Quantum phase space distributions in thermofield dynamics

It is shown that the 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. PACS No: 03.65. Ca, 42.50.-p ∗e-mail:[email protected] †e-mail:[email protected] ‡email:[email protected] 1