Enhanced thermodynamic efficiency in time asymmetric ratchets

TL;DR

This paper investigates how combining potential asymmetry with time asymmetric forcing enhances the efficiency of Brownian ratchets, highlighting the suppression of backward current and the effects of thermal fluctuations.

Contribution

It corrects a previous error and demonstrates that potential and temporal asymmetries significantly improve efficiency without fine tuning, also exploring current reversals and entropy relations.

Findings

Enhanced efficiency due to combined asymmetries

Suppression of backward current as efficiency mechanism

Thermal fluctuations can optimize energy transduction

Abstract

The energetic efficiency of an overdamped Brownian particle in a saw tooth potential in the presence of time asymmetric forcing is studied in the adiabatic limit. An error made in the earlier work on the same problem in literature is corrected. We find that asymmetry in potential together with temporal asymmetry in forcing leads to much enhanced efficiency without fine tuning of parameters. The origin of this is traced to the suppression of backward current. We also present a comparative study between the role of continuous and discontinuous ratchet forces on these measurable quantities. We find that the thermal fluctuations can optimize the energy transduction, the range of parameters, however, being very small. This ratchet model also displays current reversals on tuning of parameters even in the adiabatic regime. The possible relationships between nature of currents, entropy production and input energy are also addressed.