Friction forces on atoms after acceleration

TL;DR

This paper revisits quantum friction on atoms near surfaces, showing the dependence on acceleration history and revealing a subtle cancellation affecting the leading order velocity dependence of the frictional power.

Contribution

It clarifies how the initial acceleration affects quantum friction calculations and uncovers a cancellation that alters the expected velocity scaling of dissipated power.

Findings

Friction force depends on how the atom is accelerated.

Leading order dissipated power scales as v^4 due to cancellation.

Alternative calculation confirms the v^3 scaling of radiation force.

Abstract

The aim of this paper is to revisit the calculation of atom-surface quantum friction in the quantum field theory formulation put forward by Barton [New J. Phys. 12 (2010) 113045]. We show that the power dissipated into field excitations and the associated friction force depend on how the atom is boosted from being initially at rest to a configuration in which it is moving at constant velocity (v) parallel to the planar interface. In addition, we point out that there is a subtle cancellation between the one-photon and part of the two-photon dissipating power, resulting in a leading order contribution to the frictional power which goes as v^4. These results are also confirmed by an alternative calculation of the average radiation force, which scales as v^3.