Quantum Rolling Friction

TL;DR

This paper explores how quantum fluctuations and light-matter interactions induce a novel form of friction on an atom moving near a surface, revealing complex velocity-dependent rotational effects akin to classical rolling friction.

Contribution

It introduces a non-Markovian, nonequilibrium framework to analyze quantum friction, highlighting the role of spin-momentum locking and Doppler effects in atom-surface interactions.

Findings

Velocity-dependent rotational dynamics of the atom.

Counterintuitive features in quantum drag force.

Potential for tuning atom-surface interactions.

Abstract

An atom moving in a vacuum at constant velocity and parallel to a surface experiences a frictional force induced by the dissipative interaction with the quantum fluctuations of the electromagnetic field. We show that the combination of nonequilibrium dynamics, anomalous Doppler effect and spin-momentum locking of light mediates an intriguing interplay between the atom's translational and rotational motion. In turn, this deeply affects the drag force in a way that is reminiscent of classical rolling friction. Our fully non-Markovian and nonequilibrium description reveals counterintuitive features characterizing the atom's velocity-dependent rotational dynamics. These results prompt interesting directions for tuning the interaction and for investigating nonequilibrium dynamics as well as the properties of confined light.