Coherent Cooper-pair pumping by magnetic flux control

TL;DR

This paper presents a novel scheme for Cooper-pair pumping using magnetic flux control, enabling charge transfer without electrostatic modulation and revealing phase-dependent pumped charge behavior.

Contribution

It introduces a new adiabatic magnetic flux-based method for Cooper-pair pumping, differing from previous electrostatic approaches.

Findings

Pumped charge depends on the superconducting phase bias.

Maximum charge transfer occurs at phase bias of {} and {\u00b5}

Large charge transfer possible in a single cycle at phase bias of .

Abstract

We introduce and discuss a scheme for Cooper-pair pumping. The scheme relies on the coherent transfer of a superposition of charge states across a superconducting island and is realized by adiabatic manipulation of magnetic fluxes. Differently from previous implementations, it does not require any modulation of electrostatic potentials. We find a peculiar dependence of the pumped charge on the superconducting phase bias across the pump and that an arbitrarily large amount of charge can be pumped in a single cycle when the phase bias is {\pi}. We explain these features and their relation to the adiabatic theorem.