  We introduce the idea of actually cooling quantum systems by means of
incoherent thermal light, hence giving rise to a counter-intuitive mechanism of
"cooling by heating". In this effect, the mere incoherent occupation of a
quantum mechanical mode serves as a trigger to enhance the coupling between
other modes. This notion of effectively rendering states more coherent by
driving with incoherent thermal quantum noise is applied here to the
opto-mechanical setting, where this effect occurs most naturally. We discuss
two ways of describing this situation, one of them making use of stochastic
sampling of Gaussian quantum states with respect to stationary classical
stochastic processes. The potential of experimentally demonstrating this
counter-intuitive effect in opto-mechanical systems with present technology is
sketched.
