  We study the mechanical effects of light on an atom trapped in a harmonic
potential when an atomic dipole transition is driven by a laser and it is
strongly coupled to a mode of an optical resonator. We investigate the cooling
dynamics in the bad cavity limit, focussing on the case in which the effective
transition linewidth is smaller than the trap frequency, hence when sideband
cooling could be implemented. We show that quantum correlations between the
mechanical actions of laser and cavity field can lead to an enhancement of the
cooling efficiency with respect to sideband cooling. Such interference effects
are found when the resonator losses prevail over spontaneous decay and over the
rates of the coherent processes characterizing the dynamics.
