Probing coherent Cooper pair splitting with cavity photons

TL;DR

This paper proposes using microwave cavity frequency shifts to directly probe the coherence of Cooper pair splitting in a nanocircuit, demonstrating a novel method to investigate quantum transport phenomena.

Contribution

It introduces a theoretical framework for detecting coherent Cooper pair injection via cavity frequency pull modifications in a coupled microwave cavity and CPS system.

Findings

Cavity frequency pull exhibits an anticrossing linked to coherent Cooper pair injection.

Resonant CPS modifies the cavity frequency pull, enabling coherence detection.

Microwave cavities can serve as powerful tools for probing quantum transport in nanocircuits.

Abstract

This work discusses theoretically the behavior of a microwave cavity and a Cooper pair beam splitter (CPS) coupled non-resonantly. The cavity frequency pull is modified when the CPS is resonant with a microwave excitation. This provides a direct way to probe the coherence of the Cooper pair splitting process. More precisely, the cavity frequency pull displays an anticrossing whose specificities can be attributed unambiguously to coherent Cooper pair injection. This work illustrates that microwave cavities represent a powerful tool to investigate current transport in complex nanocircuits.