Classical and quantum pumping in closed systems

TL;DR

This paper investigates charge pumping in closed systems, analyzing classical and quantum cases, and relates deviations from quantization to conductance, using Kubo formalism and explicit models.

Contribution

It introduces a unified Kubo-based approach to analyze both dissipative and adiabatic charge pumping in closed systems, including quantum models.

Findings

Charge pumping deviation relates to Thouless conductance.

Explicit calculation for a 3-site quantum pump.

Comparison of classical and quantum pumping mechanisms.

Abstract

Pumping of charge (Q) in a closed ring geometry is not quantized even in the strict adiabatic limit. The deviation form exact quantization can be related to the Thouless conductance. We use Kubo formalism as a starting point for the calculation of both the dissipative and the adiabatic contributions to Q. As an application we bring examples for classical dissipative pumping, classical adiabatic pumping, and in particular we make an explicit calculation for quantum pumping in case of the simplest pumping device, which is a 3 site lattice model.