Dissipation Enhanced Asymmetric Transport in Quantum Ratchets

TL;DR

This paper theoretically investigates how dissipation and weak oscillating fields induce asymmetric tunneling and unidirectional current in quantum ratchets, revealing dissipation's role in enhancing quantum transport asymmetry.

Contribution

It introduces a semi-classical model showing dissipation enhances asymmetry and steady current in quantum ratchets without macroscopic field gradients.

Findings

Dissipation amplifies tunneling asymmetry.

Weak oscillating fields induce unidirectional current.

Quantum ratchet behavior emerges without macroscopic field gradients.

Abstract

Quantum mechanical motion of a particle in a periodic asymmetric potential is studied theoretically at zero temperature. It is shown based on semi-classical approximation that the tunneling probability from one local minimum to the next becomes asymmetric in the presence of weak oscillating field, even though there is no macroscopic field gradient in average. Dissipation enhances this asymmetry, and leads to a steady unidirectional current, resulting in a quantum ratchet system.