Floquet scattering theory of quantum pumps

TL;DR

This paper develops a Floquet scattering theory to analyze quantum pumps in mesoscopic conductors, predicting a sign reversal of pumped current at specific frequencies, which enables phase measurement of transmission coefficients.

Contribution

It introduces a comprehensive Floquet scattering framework for quantum pumping, including nonequilibrium distributions and current analysis at various frequencies and amplitudes.

Findings

Sign reversal of pumped current at the level spacing frequency

Ability to measure transmission phase via current sign change

Conditions for symmetry requirements in quantum pumping

Abstract

We develop the Floquet scattering theory for quantum mechanical pumping in mesoscopic conductors. The nonequilibrium distribution function, the dc charge and heat currents are investigated at arbitrary pumping amplitude and frequency. For mesoscopic samples with discrete spectrum we predict a sign reversal of the pumped current when the pump frequency is equal to the level spacing in the sample. This effect allows to measure the phase of the transmission coefficient through the mesoscopic sample. We discuss the necessary symmetry conditions (both spatial and temporal) for pumping.