The second order magnetic field gradient induced strong coupling between nitrogen-vacancy centers and a mechanical oscillator

TL;DR

This paper demonstrates how second order magnetic field gradients can strongly couple a diamond cantilever's mechanical mode with an NV center, enabling high-fidelity quantum state transfer, entanglement, and two-mode squeezing.

Contribution

It introduces a novel scheme utilizing second order magnetic gradients to enhance NV-mechanical coupling and realize quantum information protocols.

Findings

High fidelity quantum state transfer achievable

Entanglement generation between NV and mechanical oscillator

Large two-mode squeezing demonstrated under experimental conditions

Abstract

We consider a cantilever mechanical oscillator(MO) made of diamond. There is a nitrogen-vacancy(NV) center at the end of the cantilever. Two magnetic tips induce strong second order magnetic field gradient near the NV center. Under a coherent driving on MO, we find that the coupling between the MO and the NV center can be greatly enhanced. We studied how to realize quantum state transfer between MO and NV center and generate entanglement between them. We also proposed a scheme to generate the two-mode squeezing between different MO modes by coupling them to the same NV center. The decoherence and dissipation effects for both MO and NV center are numerically calculated by taking the present experimental parameters. It is found that high fidelity quantum state transfer, entanglement generation, and large two-mode squeezing could be achieved.