Directed transport of Brownian particles in a double symmetric potential

TL;DR

This paper explores how Brownian particles can exhibit directed motion in symmetric potentials by breaking transition rate symmetry, with potential applications in cold atom systems.

Contribution

It introduces a novel mechanism for directed transport in symmetric potentials through transition rate asymmetry, without breaking spatial or temporal symmetry.

Findings

Directed transport occurs despite symmetric Hamiltonians.

Breaking transition rate symmetry induces net particle motion.

Potential realization in cold atom optical lattices is discussed.

Abstract

We investigate the dynamics of Brownian particles in internal state- dependent symmetric and periodic potentials. Although no space or time symmetry of the Hamiltonian is broken, we show that directed transport can appear. We demonstrate that the directed motion is induced by breaking the symmetry of the transition rates between the potentials when these are spatially shifted. Finally, we discuss the possibility of realizing our model in a system of cold particles trapped in optical lattices.