Pumping through a quantum dot in the proximity of a superconductor

TL;DR

This paper develops a generalized formula for adiabatic charge pumping through a quantum dot near a superconductor, analyzing non-interacting and strongly interacting cases, revealing the superconductor's influence on pumped charge.

Contribution

It introduces a generalized relation between pumped charge and Green's function for quantum dots with superconducting leads, extending previous models to include superconducting proximity effects.

Findings

The formula accurately predicts pumped charge in non-interacting quantum dots across temperature regimes.

Superconducting proximity modifies the pumped charge significantly in the strongly interacting regime.

Comparison shows differences between normal and superconducting lead configurations in charge pumping behavior.

Abstract

We study adiabatic pumping through a quantum dot tunnel-coupled to one normal and one superconducting lead. We generalize a formula which relates the pumped charge through a quantum dot with Coulomb interaction to the instantaneous local Green's function of the dot, to systems containing a superconducting lead. First, we apply this formula to the case of a non-interacting, single-level quantum dot in different temperature regimes and for different parameter choices, and we compare the results with the case of a system comprising only normal leads. Then we study the infinite-U Anderson model with a superconducting lead at zero temperature, and we discuss the effect of the proximity of the superconductor on the pumped charge.