Towards A Programmable Nanomechanical Interface for Mediating Spin-Spin Interactions

Abstract

Solid state spin qubits are promising candidates for quantum information processing. In particular, the nitrogen vacancy (NV) center in diamond is known to have coherence times exceeding milliseconds even at room temperature. However, due to the limits of qubit fabrication and the short-range nature of magnetic dipolar interactions, it remains difficult to generate programmable interactions between a large number of NV centers. To address this challenge, it has been proposed to use nanomechanical resonators as a mesoscopic interface between solid state spin qubits. In this thesis, I will describe experimental efforts in building a scanning probe platform, where individual NV centers in diamond nanopillars are coupled to magnetially functionalized silicon nitride mechanical resonators. The scanning probe configuration enables programmable connectivity via mechanical transport of the nanopillars. Proof-of-principle measurements show that the coherence of the NV center is preserved despite relative movement in a magnetic field gradient, by utilizing the nitrogen nuclear spin as a quantum memory. I will also describe measurements of the spin-mechanical coupling via both DC and AC magnetometry. Finally, I present some preliminary results related to sensing of a single NV center with the mechanical resonator, which demonstrate the high level of control over each subsystem. With realistic improvements to several system parameters, high spin-mechanical cooperativities are feasible, offering a new avenue towards scalable quantum information processing with spin qubits.