Impact of Chiral-Transitions in Quantum Friction

TL;DR

This paper explores how chiral-transitions influence quantum friction on a moving atom near a surface, revealing handedness-dependent effects and unexpected behaviors contrary to classical spin-momentum expectations.

Contribution

It introduces the concept that atomic transition handedness can significantly modulate quantum friction, providing new insights into chiral effects in atom-surface interactions.

Findings

Friction force depends on the handedness of the atomic transition dipole moment.

Certain handedness enhances the quantum friction force, while the opposite suppresses it.

The observed effects contradict classical spin-momentum locking expectations.

Abstract

We theoretically investigate the role of chiral-transitions in the quantum friction force that acts on a two-level atom that moves with relative velocity v parallel to a planar metallic surface. We find that the friction force has a component that is sensitive to the handedness of the atomic transition dipole moment. In the particular, we show that the friction force can be enhanced by an atomic transition with a dipole moment with a certain handedness, and almost suppressed by the dipole moment with the opposite handedness. Curiously, the handedness of the transition dipole moment that boosts the ground-state friction force is the opposite of what is classically expected from the spin-momentum locking. We explain this discrepancy in terms of the interaction between positive and negative frequency oscillators.