Atomic Zitterbewegung

TL;DR

This paper explores the relativistic-like trembling motion (Zitterbewegung) of ultra-cold atoms governed by a Dirac-type equation, revealing damping effects due to finite wave packet width.

Contribution

It demonstrates how optically induced gauge potentials can simulate Dirac dynamics in ultra-cold atoms and analyzes the damping of Zitterbewegung caused by wave packet effects.

Findings

Zitterbewegung can be simulated with ultra-cold atoms using gauge potentials.

Finite wave packet width induces damping in the trembling motion.

The Dirac-like dynamics are experimentally realizable with current techniques.

Abstract

Ultra-cold atoms which are subject to ultra-relativistic dynamics are investigated. By using optically induced gauge potentials we show that the dynamics of the atoms is governed by a Dirac type equation. To illustrate this we study the trembling motion of the centre of mass for an effective two level system, historically called Zitterbewegung. Its origin is described in detail, where in particular the role of the finite width of the atomic wave packets is seen to induce a damping of both the centre of mass dynamics and the dynamics of the populations of the two levels.