Vacuum friction on a rotating pair of atoms

TL;DR

This paper investigates the quantum vacuum-induced frictional torque on a rotating pair of atoms, revealing a tiny but potentially significant braking force that could influence atomic interactions and irreversibility.

Contribution

It introduces a semi-classical calculation of vacuum friction on rotating atoms considering full electrostatic coupling, highlighting a new atomic-scale friction phenomenon.

Findings

Torque proportional to angular velocity and cube of fine structure constant

Friction torque can induce dimer formation in collisions

Suggests a paradigm shift in understanding irreversibility at atomic level

Abstract

Zero-point quantum fluctuations of the electromagnetic vacuum create the widely known London-van der Waals attractive force between two atoms. Recently, there was a revived interest in the interaction of rotating matter with the quantum vacuum. Here, we consider a rotating pair of atoms maintained by London van der Waals forces and calculate the frictional torque they experience due to zero-point radiation. Using a semi-classical framework derived from the Fluctuation Dissipation Theorem, we take into account the full electrostatic coupling between induced dipoles. Considering the case of zero temperature only, we find a braking torque proportional to the angular velocity and to the third power of the fine structure constant. Although very small compared to London van der Waals attraction, the torque is strong enough to induce the formation of dimers in binary collisions. This new friction phenomenon at the atomic level should induce a paradigm change in the explanation of irreversibility.