Optimization of optomechanical cooling and entanglement using semianalytic solutions to the Lindblad master equation

We solve the Lindblad master equation for the quantum state of a pumped optomechanical system coupled to a thermal bath. We show that the solution to the state in the linear pumping regime is a beam-split thermal state when pumped on the red sideband of cavity resonance and a two-mode squeezed thermal state when pumped on the blue sideband. The time dependence of each state is fully described by four coupled differential equations. Using this formalism, we describe a process of first cooling the mechanical mode via the red-sideband pump, then entangling that mode using the blue-sideband pump. We find that there is an optimal strength of blue-sideband pumping to drive the correlation variance between the two modes below a desired threshold for a maximum amount of time. This optimal value depends both on the loss rates and equilibrium temperatures of the two modes, and we provide an approximate analytic expression for this relationship. We show that a long entanglement time is achievable, even at relatively high temperatures, as long as the optical loss rate is much higher than the mechanical one.