What is Quantum in Quantum Pumping: The Role of Phase and Asymmetries

TL;DR

This paper clarifies that quantum pumping can occur without quantum phases, identifying different process types and revealing hidden antisymmetric components affecting current without net charge transfer.

Contribution

It demonstrates that quantum pumping includes both phase-dependent and independent processes and uncovers hidden antisymmetric contributions to current.

Findings

Quantum pumping does not always require quantum phases.

Some processes rely intrinsically on phase, others do not.

Hidden antisymmetric components can significantly influence current.

Abstract

We show that quantum pumping does not always require a quantum description or a quantum phase. Quantum pumping is shown to encompass different types of processes, some of which intrinsically rely on phase while others do not. We also show that many pumping processes have a hidden antisymmetric component that contributes significantly to the instantaneous current at the terminals without causing net charge transfer in a period. We have also computed the exact pumped current for some cases over a full range of time variation from adiabatic to non-adiabatic.