Control of Andreev bound state population and related charge-imbalance effect

TL;DR

This paper investigates how ac-driven superconducting constrictions can control Andreev bound state populations and induce charge imbalance, revealing phase-dependent charge asymmetries with potential experimental implications.

Contribution

It introduces a method to control Andreev bound states and explores the resulting charge imbalance effects in superconducting constrictions.

Findings

Control of Andreev bound state populations demonstrated.

Charge imbalance depends on the superconducting phase.

Charge asymmetry in quasiparticle processes identified.

Abstract

Motivated by recent experimental research, we study the processes in an ac driven superconducting constriction whereby one quasiparticle is promoted to the delocalized states outside the superconducting gap. We demonstrate that with these processes one can control the population of the Andreev bound states in the constriction. We stress an interesting charge asymmetry of these processes that may produce a charge imbalance of accumulated quasiparticles, which depends on the phase.