Relaxation Processes in Dipole-Coupled Nitrogen-Vacancy Centers in Zero Field: Application in Magnetometry

Abstract

We study relaxation processes in dipolar-coupled negatively charged nitrogen-vacancy (N-V − ) centers close to zero field. Specifically, we uncover regimes where flip-flop and double-flip processes, as well as mixing induced by local electric fields, play a significant role in N-V-N-V cross relaxation. Our results are relevant for understanding decoherence in many-body spin systems, as well as for high-sensitivity magneto-and electrometry with long-lived interacting solid-state spins. As a proof of principle, we present an orientation and microwave-free magnetometer based on cross relaxation.