Quantum noise interference and backaction cooling in cavity nanomechanics.

We present a theoretical analysis of a novel cavity electromechanical system where a mechanical resonator directly modulates the damping rate kappa of a driven electromagnetic cavity. We show that via a destructive interference of quantum noise, the driven cavity can effectively act like a zero-temperature bath irrespective of the ratio kappa/omega_{M}, where omega_{M} is the mechanical frequency. This scheme thus allows one to cool the mechanical resonator to its ground state without requiring the cavity to be in the so-called good cavity limit kappa << omega_{M}. The system described here could be implemented directly using setups similar to those used in recent experiments in cavity electromechanics.