Reversing non-local transport through a superconductor by electromagnetic excitations

TL;DR

This paper demonstrates how electromagnetic excitations can control non-local electron transport in superconductor-normal metal systems, potentially enabling manipulation of entangled electron pairs for quantum applications.

Contribution

It introduces a method to reverse non-local transport in superconductors using electromagnetic excitations, providing new insights into controlling entangled electron states.

Findings

Electromagnetic excitations influence the balance of non-local transport processes.

Control of non-local conductance depends on the spatial symmetry of excitations.

Findings explain recent experimental observations and suggest new control strategies.

Abstract

Superconductors connected to normal metallic electrodes at the nanoscale provide a potential source of non-locally entangled electron pairs. Such states would arise from Cooper pairs splitting into two electrons with opposite spins tunnelling into different leads. In an actual system the detection of these processes is hindered by the elastic transmission of individual electrons between the leads, yielding an opposite contribution to the non-local conductance. Here we show that electromagnetic excitations on the superconductor can play an important role in altering the balance between these two processes, leading to a dominance of one upon the other depending on the spatial symmetry of these excitations. These findings allow to understand some intriguing recent experimental results and open the possibility to control non-local transport through a superconductor by an appropriate design of the experimental geometry.