Spectroscopic signatures of quantum friction

TL;DR

This paper derives a formula for atomic energy level shifts and decay rates near a surface, revealing how these quantities depend on atomic velocity and motion angle, with implications for observing quantum friction.

Contribution

It introduces a Markovian framework with complex Doppler shifts to analytically describe velocity-dependent atomic level shifts and decay rates near surfaces.

Findings

Parallel motion results are quadratic or higher in velocity.

Perpendicular motion shows linear velocity dependence.

Results suggest experimental probing of quantum friction is feasible.

Abstract

We present a formula for the spectroscopically accessible level shifts and decay rates of an atom moving at an arbitrary angle relative to a surface. Our Markov formulation leads to an intuitive analytic description whereby the shifts and rates are obtained from the coefficients of the Heisenberg equation of motion for the atomic flip operators but with complex Doppler-shifted (velocity-dependent) transition frequencies. Our results conclusively demonstrate that for the limiting case of parallel motion the shifts and rates are quadratic or higher in the atomic velocity. We show that a stronger, linear velocity dependence is exhibited by the rates and shifts for perpendicular motion, thus opening the prospect of experimentally probing the Markovian approach to the phenomenon of quantum friction.