Cooling through parametric modulations and phase-preserving quantum measurements

Abstract

We propose a cooling protocol that uses phase-preserving quantum measurements and phasedependent modulations of the trapping potential at parametric resonance to cool a quantum oscillator to near its quantum-mechanical ground-state. The sequential measurements and feedback provide a definite phase reference and stabilize the oscillator in the long-time limit. The protocol is robust against moderate amounts of dissipation and phase errors in the feedback loop. Our work has implications for the cooling of mechanical resonators and the integration of quantum refrigerators into quantum circuits.