Sympathetic cooling and squeezing of two colevitated nanoparticles

Levitated particles are an ideal tool for measuring weak forces and investigating quantum mechanics in macro-scopic objects. Arrays of two or more of these particles have been suggested for improving force sensitivity and entangling macroscopic objects. In this article, two charged, silica nanoparticles, that are coupled through their mutual Coulomb repulsion, are trapped in a Paul trap, and the individual masses and charges of both particles are characterized. We demonstrate sympathetic cooling of one nanoparticle coupled via the Coulomb interaction to the second nanoparticle to which feedback cooling is directly applied. We also implement sympathetic squeezing through a similar process showing nonthermal motional states can be transferred by the Coulomb interaction. This work establishes protocols to cool and manipulate arrays of nanoparticles for sensing and minimizing the effect of optical heating in future experiments.

Automated summary

This article investigates the use of levitated particles as an ideal tool for measuring weak forces and studying quantum mechanics in macroscopic objects. Two charged silica nanoparticles are trapped in a Paul trap and their individual masses and charges are characterized. The article demonstrates the cooling and manipulation of the nanoparticles through the Coulomb interaction, and establishes protocols for future experiments involving arrays of nanoparticles.