# Controlling the net charge on a nanoparticle optically levitated in vacuum

## TL;DR

This paper introduces a simple method to control the net charge of an optically levitated nanoparticle in vacuum, which is crucial for reducing dephasing and testing quantum mechanics.

## Contribution

A novel, straightforward technique for controlling nanoparticle charge via electric discharge without extra optics or mechanics.

## Key findings

- Effective charge control demonstrated in vacuum conditions
- Reduces Coulomb-induced dephasing of levitated particles
- Facilitates quantum physics experiments with levitated nanoparticles

## Abstract

Optically levitated nanoparticles in vacuum are a promising model system to test physics beyond our current understanding of quantum mechanics. Such experimental tests require extreme control over the dephasing of the levitated particle's motion. If the nanoparticle carries a finite net charge, it experiences a random Coulomb force due to fluctuating electric fields. This dephasing mechanism can be fully excluded by discharging the levitated particle. Here, we present a simple and reliable technique to control the charge on an optically levitated nanoparticle in vacuum. Our method is based on the generation of charges in an electric discharge and does not require additional optics or mechanics close to the optical trap.