Cooling of the rotation of a nanodiamond via the interaction with the electron spin of the contained NV-center

TL;DR

This paper presents a method to cool the rotation of a levitated nanodiamond containing an NV-center by exploiting spin-rotation coupling and optical pumping, potentially reaching the quantum rotational regime.

Contribution

The authors introduce a novel scheme for rotational cooling of nanodiamonds using NV-center spin interactions and optical pumping, with analytical and theoretical analysis of the damping process.

Findings

Analytical expression for damping torque on nanodiamond

Evaluation of final cooling temperature using fluctuation-dissipation theorem

Potential to reach quantum rotational regime

Abstract

We propose a way to cool the rotation of a nanodiamond, which contains a NV-center and is levitated by an optical tweezer. Following the rotation of the particle, the NV-center electron spin experiences varying external fields and so leads to spin-rotation coupling. By optically pumping the electrons from a higher energy level to a lower level, the rotation energy is dissipated. We give the analytical result for the damping torque exerted on the nanodiamond, and evaluate the final cooling temperature by the fluctuation-dissipation theorem. It's shown that the quantum regime of the rotation can be reached with our scheme.