Underdamped quantum ratchets

TL;DR

This paper explores how weak dissipation can induce a quantum ratchet current through symmetry violations and bath-induced superpositions, revealing a novel mechanism for directed quantum transport.

Contribution

It introduces a Floquet-Markov master equation approach to analyze dissipation effects, predicting a dissipation-induced quantum ratchet current under time-reversal symmetric driving.

Findings

Dissipation can generate quantum ratchet currents even with symmetric driving.

Quantum ratchet current arises from bath-induced superpositions of Floquet states.

The study provides a new understanding of quantum transport mechanisms under weak dissipation.

Abstract

We investigate the quantum ratchet effect under the influence of weak dissipation which we treat within a Floquet-Markov master equation approach. A ratchet current emerges when all relevant symmetries are violated. Using time-reversal symmetric driving we predict a purely dissipation-induced quantum ratchet current. This directed quantum transport results from bath-induced superpositions of non-transporting Floquet states.