Coherent Control of a Nitrogen-Vacancy Center Spin Ensemble with a Diamond Mechanical Resonator

TL;DR

This paper demonstrates that a diamond mechanical resonator can coherently control NV center spins, including the forbidden $|-1> o |+1>$ transition, using high-frequency stress, expanding the methods for quantum spin manipulation.

Contribution

It introduces mechanical stress as a new method for coherent control of NV center spins, including the forbidden transition, using a bulk-mode diamond microresonator.

Findings

Mechanical stress drives Rabi oscillations between $|-1>$ and $|+1>$ states.

Measured spin dephasing times with mechanical and magnetic Ramsey sequences.

Demonstrated coherent mechanical control of NV center spins, enabling new quantum control schemes.

Abstract

Coherent control of the nitrogen-vacancy (NV) center in diamond's triplet spin state has traditionally been accomplished with resonant ac magnetic fields under the constraint of the magnetic dipole selection rule, which forbids direct control of the $|-1>\leftrightarrow |+1>$ spin transition. We show that high-frequency stress resonant with the spin state splitting can coherently control NV center spins within this subspace. Using a bulk-mode mechanical microresonator fabricated from single-crystal diamond, we apply intense ac stress to the diamond substrate and observe mechanically driven Rabi oscillations between the $|-1>$ and $|+1>$ states of an NV center spin ensemble. Additionally, we measure the inhomogeneous spin dephasing time ($T_{2}^{*}$) of the spin ensemble using a mechanical Ramsey sequence and compare it to the dephasing times measured with a magnetic Ramsey sequence for each of the three spin qubit combinations available within the NV center ground state. These results demonstrate coherent spin driving with a mechanical resonator and could enable the creation of a phase-sensitive $\Delta$-system within the NV center ground state.