Pursuing many-body dynamics of NV centers in diamond

We describe experimental steps toward the observation of many-body dynamics in optically-addressable spin ensembles (NV centers) in diamond. We study the effect of electron irradiation using a 200 keV transmission electron microscope (TEM) on the conversion efficiency and the coherence times of various types of diamond samples with different initial nitrogen concentrations. Using nuorescence images obtained by confocal microscopy, we observe an order of magnitude improvement in the NV concentration (up to ~ 1011 NV/cm²), without any degradation in their coherence times of ~ 180 μs (for a Hahn-Echo experiment). We address the potential of this technique for studying many-body physics of ensembles of NV spins: our simulations show that by implementing a simple dynamical decoupling protocol, dipolar interactions could be distinguished from ordinary interactions with the spin-bath environment. These outcomes could contribute to the creation of non-classical spin states, e.g. for quantum sensing.