Directional entanglement of spin-orbit locked nitrogen-vacancy centers by magnons

TL;DR

This paper demonstrates that nitrogen-vacancy centers in diamond can emit spin-momentum locked magnetic fields, enabling unidirectional magnon excitation and chiral quantum entanglement, which could be useful for quantum information devices.

Contribution

It introduces a method for directional magnon excitation and entanglement using NV centers, highlighting a new way to control quantum states via spin-momentum locking.

Findings

NV centers emit spin-momentum locked stray fields

Magnons can be excited unidirectionally by NV centers

NV centers enable chiral quantum entanglement

Abstract

We address that the stray magnetic field emitted by the excited quantum states of the nitrogen-vacancy (NV) centers is spin-momentum locked, such that the spin transfer to nearby ferromagnetic nanostructures is unidirectional. This may allow the controlled excitation of propagating magnons by NV centers in diamond. A pair of NV spin qubits exchange virtual magnons in a magnetic nanowire in a chiral manner that leads to directional quantum entanglement. A magnon-based ``quantum-entanglement isolator" should be a useful device in future quantum information technology.