Simultaneous cavity cooling of all six degrees of freedom of a levitated nanoparticle

Year: 2023

Authors: Pontin A., Fu H., Toros M., Monteiro T.S., Barker P.F.

Autors Affiliation: UCL, Dept Phys & Astron, London, England; Univ Glasgow, Sch Phys & Astron, Glasgow, Scotland.

Abstract: Optically trapped and levitated nanoparticles can be used to study macroscopic quantum effects, but fully controlling their motion is difficult. Now, all six roto-translational degrees of freedom have been cooled, although not to the quantum ground state. Controlling the motional degrees of isolated, single nanoparticles trapped within optical fields in a high vacuum are seen as ideal candidates for exploring the limits of quantum mechanics in a new mass regime. These systems are also massive enough to be considered for future laboratory tests of the quantum nature of gravity. Recently, the translational motion of trapped particles has been cooled to microkelvin temperatures, but controlling all the observable degrees of freedom, including their orientational motion, remains an important goal. Here we report the control and cooling of all the translational and rotational degrees of freedom of a nanoparticle trapped in an optical tweezer, accomplished by cavity cooling via coherent elliptic scattering. We reached temperatures in the range of hundreds of microkelvins for the translational modes and temperatures as low as 5 mK for the librational degrees of freedom. This work brings within reach applications in quantum science and the study of single isolated nanoparticles via imaging and diffractive methods, free of interference from a substrate.

Journal/Review: NATURE PHYSICS

Volume: 19 (7)      Pages from: 1003  to: +

More Information: Acknowledgements: A.P. thanks F. Marin for useful discussions. We acknowledge funding from EPSRC grant no. EP/N031105/1 and EP/S000267/1 . H.F. acknowledges the Engineering and Physical Sciences Research Council (grant no. EP/L015242/1). M.T. acknowledges funding by the Leverhulme Trust (RPG-2020-197).
KeyWords: Quantum Control
DOI: 10.1038/s41567-023-02006-6