Mechanical driving of nitrogen-vacancy centers in diamond*

We theoretically investigate high-frequency phonon-mediated dynamic mechanical driving of spin transitions in nitrogen-vacancy centers in diamond (NV^-). Mechanical driving is parity non-conserving and can allow quantum control of spin |-1〉↔ |+1〉transitions that cannot be addressed using magnetic resonant fields [1,2]. By applying high-frequency mechanical stress, the electronic and nuclear spin interaction is averaged out in the manifold of the |-1〉↔ |+1〉spin transition. This dynamic decoupling yields an increase in the nuclear dephasing time. Experimentally, fivefold longer times were demonstrated using a.c. stress generated by a diamond mechanical resonator [1]. We develop a theoretical framework for this increase in the dephasing time for dynamic mechanical driving. Exploring mechanical driving to induce entanglement aims to engineer NV ensemble entanglement at room temperature to increase sensitivity in quantum metrology.

[1] ER MacQuarrie et al., Coherent control of a nitrogen-vacancy center spin ensemble with a diamond mechanical resonator, Optica, 2015 [2] SD Bennett et al., Phonon-Induced Spin-Spin Interactions in Diamond Nanostructures: Application to Spin Squeezing,PRL, 2013.