Surface-induced decoherence and heating of charged particles

TL;DR

This paper develops a theoretical framework to understand how nearby surfaces cause decoherence and heating in levitated charged particles, crucial for quantum applications involving such systems.

Contribution

It introduces a comprehensive set of master equations that model surface-induced effects on the quantum dynamics of charged particles near metallic and dielectric surfaces.

Findings

Master equations accurately describe surface-induced decoherence and heating.

Surface effects scale with frequency and distance as observed experimentally.

Tools enable mitigation strategies for surface-induced decoherence.

Abstract

Levitating charged particles in ultra-high vacuum provides a preeminent platform for quantum information processing, for quantum-enhanced force and torque sensing, for probing physics beyond the standard model, and for high-mass tests of the quantum superposition principle. Existing setups range from single atomic ions, to ion chains and crystals, to charged molecules and nanoparticles. Future technological applications of such quantum systems will be crucially affected by fluctuating electric fields emanating from nearby electrodes, which interact with the levitated particles' monopole and higher charge moments. In this article, we provide a theoretical toolbox for describing how the rotational and translational quantum dynamics of charged nano- to microscale objects is affected by near metallic and dielectric surfaces, as characterized by their macroscopic dielectric response. The resulting quantum master equations describe the coherent surface-particle interaction, due to image charges and Casimir-Polder potentials, as well as surface-induced decoherence and heating, with the experimentally observed frequency and distance scaling. We explicitly evaluate the master equations for typical charge distributions and types of motion, thereby providing the tools required for describing and mitigating surface-induced decoherence in a variety of experiments with charged objects.