Quantum Ratchets at High Temperatures

TL;DR

This paper investigates quantum ratchets at high temperatures using phase-space methods, revealing how quantum effects like tunneling influence directed currents and decoherence.

Contribution

It introduces a phase-space approach to analyze quantum ratchets at high temperatures, highlighting quantum effects on classical ratchet behavior.

Findings

Quantum tunneling modifies classical ratchet currents.

Decoherence impacts the stability of directed transport.

High-temperature regime still exhibits quantum effects.

Abstract

Using the continued-fraction method we solve the Caldeira-Leggett master equation in the phase-space (Wigner) representation to study Quantum ratchets. Broken spatial symmetry, irreversibility and periodic forcing allows for a net current in these systems. We calculate this current as a function of the force under adiabatic conditions. Starting from the classical limit we make the system quantal. In the quantum regime tunnel events and over-barrier wave reflection phenomena modify the classical result. Finally, using the phase-space formalism we give some insights about the decoherence in these systems.