Proposal for a Bell test in cavity optomagnonics

TL;DR

This paper proposes a method to perform a Bell test in cavity optomagnonics, demonstrating potential for verifying entanglement and advancing quantum information processing in macroscopic systems.

Contribution

It introduces a novel scheme to generate and detect entanglement between magnons and photons in cavity optomagnonics for Bell inequality testing.

Findings

Significant Bell inequality violation achievable in weak-coupling regime

Entanglement between magnons and photons can be verified

Platform suitable for quantum information tasks

Abstract

We present a proposal to test Bell inequality in the emerging field of cavity optomagnonics, where a sphere of ferromagnetic crystal supports two optical whispering gallery modes and one magnon mode. The two optical modes are driven by two laser pulses, respectively. Entanglement between magnon mode and one of the two optical modes will be generated by the first pulse, and the state of magnon mode is subsequently mapped into another optical mode via the second pulse. Hence correlated photon-photon pairs is created out of the cavity. A Bell test can be implemented using these pairs, which enables us to test local hidden-variable models at macroscopic optomagnonical system. Our results show that a significant violation of Bell inequality can be obtained in the experimentally relevant weak-coupling regime. The violation of Bell inequality not only verifies the entanglement between magnons and photons, but also implies that cavity optomagnonics is a promising platform for quantum information processing tasks.