Ground-state cooling of a mechanical oscillator by heating

TL;DR

This paper demonstrates a novel ground-state cooling method for a mechanical oscillator using electromagnetic noise, showing optimal cooling at specific noise bandwidths and revealing the interplay between noise characteristics and cooling efficiency.

Contribution

It introduces a refrigeration mechanism in cavity optomechanics where external noise induces ground-state cooling, a counterintuitive approach compared to traditional dissipation-based cooling.

Findings

Optimal cooling occurs with noise bandwidth smaller than the cavity decay rate.

Cooling efficiency decreases at higher noise bandwidths.

Damping follows noise amplitude adiabatically when bandwidth is comparable to mechanical damping.

Abstract

Dissipation and the accompanying fluctuations are often seen as detrimental for quantum systems, since they are associated with fast relaxation and loss of phase coherence. However, it has been proposed that a pure state can be prepared if external noise induces suitable downwards transitions, while exciting transitions are blocked. We demonstrate such a refrigeration mechanism in a cavity optomechanical system, where we prepare a mechanical oscillator in its ground state by injecting strong electromagnetic noise at frequencies around the red mechanical sideband of the cavity. The optimum cooling is reached with a noise bandwidth smaller than, but on the order of the cavity decay rate. At higher bandwidths, cooling is less efficient. In the opposite regime where the noise bandwidth becomes comparable to the mechanical damping rate, damping follows the noise amplitude adiabatically, and the cooling is also suppressed.