Driven tracer with absolute negative mobility

TL;DR

This paper demonstrates that Absolute Negative Mobility (ANM), where current flows opposite to an applied drive, can occur near equilibrium states, supported by analytical and numerical studies of lattice and Brownian disk models.

Contribution

It introduces the concept of ANM occurring around equilibrium states and provides analytical and numerical evidence using simple lattice and Brownian disk models.

Findings

ANM can occur near equilibrium states in certain models.

The lattice model predicts ANM in the linear response regime.

Numerical simulations show NDM but not ANM in Brownian disk systems.

Abstract

Instances of negative mobility, where a system responds to a perturbation in a way opposite to naive expectation, have been studied theoretically and experimentally in numerous nonequilibrium systems. In this work we show that Absolute Negative Mobility (ANM), whereby current is produced in a direction opposite to the drive, can occur around equilibrium states. This is demonstrated with a simple one-dimensional lattice model with a driven tracer. We derive analytical predictions in the linear response regime and elucidate the mechanism leading to ANM by studying the high-density limit. We also study numerically a model of hard Brownian disks in a narrow planar channel, for which the lattice model can be viewed as a toy model. We find that the model exhibits Negative Differential Mobility (NDM), but no ANM.