Cold atoms as a coolant for levitated optomechanical systems

TL;DR

This paper proposes a method to cool optically trapped nanospheres to their quantum ground state using sympathetic cooling with cold atomic gases, enabling quantum control and sensing applications.

Contribution

It introduces a novel sympathetic cooling scheme for nanospheres using atomic gases, which requires modest cavity finesse and allows dynamic control of the cooling process.

Findings

Ground state cooling of nanospheres is achievable from room temperature.

The method requires only modest cavity finesse compared to cavity cooling.

Cooling can be turned off to observe strongly-coupled atom-sphere dynamics.

Abstract

Optically trapped dielectric objects are well suited for reaching the quantum regime of their center of mass motion in an ultra-high vacuum environment. We show that ground state cooling of an optically trapped nanosphere is achievable when starting at room temperature, by sympathetic cooling of a cold atomic gas optically coupled to the nanoparticle. Unlike cavity cooling in the resolved sideband limit, this system requires only a modest cavity finesse and it allows the cooling to be turned off, permitting subsequent observation of strongly-coupled dynamics between the atoms and sphere. Nanospheres cooled to their quantum ground state could have applications in quantum information science or in precision sensing.