Entanglement witnessing in superconducting beamsplitters

TL;DR

This paper investigates how superconducting beamsplitters can be used to detect entanglement via Bell inequality violations, providing a practical method for verifying entanglement in Cooper pair splitters.

Contribution

It introduces a class of superconducting beamsplitters where Bell violation depends on detector efficiency and proposes an experiment to verify entanglement in Cooper pair splitters.

Findings

Bell parameter is a simple function of detector efficiency.

All necessary information can be obtained in Y-junction setups.

Proposes an experimentally feasible entanglement verification method.

Abstract

We analyse a large class of superconducting beamsplitters for which the Bell parameter (CHSH violation) is a simple function of the spin detector efficiency. For these superconducting beamsplitters all necessary information to compute the Bell parameter can be obtained in Y-junction setups for the beamsplitter. Using the Bell parameter as an entanglement witness, we propose an experiment which allows to verify the presence of entanglement in Cooper pair splitters.