Non-adiabatic charge pump: an exact solution

TL;DR

This paper presents an exact, non-perturbative solution for quantum charge pumps operating in the non-adiabatic regime, revealing novel plateau structures and current reversal phenomena due to multi-photon processes.

Contribution

It provides a general exact expression for current in non-adiabatic quantum charge pumps, including effects of finite frequency and amplitude, and predicts new phenomena like current plateaus and reversals.

Findings

Plateau structures in pumped current due to multi-photon processes

Current reversal when resonant level crosses Fermi energy

Exact non-perturbative expression for quantum charge pump current

Abstract

We derived a general and exact expression of current for quantum parametric charge pumps in the non-adiabatic regime at finite pumping frequency and finite driving amplitude. The non-perturbative theory predicts a remarkable plateau structure in the pumped current due to multi-photon assisted processes in a double-barrier quantum well pump involving only a {\it single} pumping potential. It also predicts a current reversal as the resonant level of the pump crosses the Fermi energy of the leads.