Towards entangling distant solid state spin qubits via mechanical resonators

Nitrogen-vacancy (NV) centers are versatile solid state spin qubits with long electron spin coherence times and nearby nuclear spins for information storage. However, deterministically entangling distant NV pairs is difficult due to their short ranged dipole-dipole interactions. Mechanical resonator has been proposed as a candidate to mediate this entanglement.

In this talk, I will describe our efforts towards a strongly coupled spin-mechanical system for future quantum information applications. More specifically, a single NV in diamond nanopillar is coupled to a clamped high-Q mechanical resonator via an attached micro-magnet. By optimizing magnetic field gradients, we have realized a spin-mechanical coupling of 30 Hz. Such a coupling strength allows us to measure the driven motion of this macroscopic resonator by a single electron spin. I will present how this measurement is performed, and discuss how this scheme can be used to conditionally prepare two distant NVs in Bell states and its potential applications in realizing a programmable NV qubit array.