Squeezed thermal states: the result of parametric down conversion in lossy cavities

We theoretically investigate the properties and temporal evolution of squeezed states generated using degenerate parametric down conversion in lossy cavities. We show that the Lindblad master equation, which governs the evolution of this system, has, as its solution, a squeezed thermal state with an effective temperature and squeezing parameter that depends on time. We derive analytical solutions for the time evolution of quadrature noise, thermal photon number, squeezing parameter, and total photon number under different pumping regimes. We also find the steady state limits of the quadrature noises and discuss the g(2) factor of the generated light inside the cavity in the steady state.