  Motivated by various systems in which quantum effects occur in classical
backgrounds, we consider the dynamics of a classical particle as described by a
coherent state that is coupled to a quantum bath via bi-quadratic interactions.
We evaluate the resulting quantum dissipation of the motion of the classical
particle. We also find classical initial conditions for the bath that
effectively lead to the same dissipation as that due to quantum effects,
possibly providing a way to approximately account for quantum backreaction
within a classical analysis.
