We present experimental observations and a study of quantum dynamics of strongly interacting electronic spins, at room temperature in the solid state. In a diamond substrate, a single nitrogen vacancy (NV) center coherently interacts with two adjacent S = 1/2 dark electron spins. We quantify NV-electron and electron-electron couplings via detailed spectroscopy, with good agreement to a model of strongly interacting spins. The electron-electron coupling enables an observation of coherent flip-flop dynamics between electronic spins in the solid state, which occur conditionally on the state of the NV. Finally, as a demonstration of coherent control, we selectively couple and transfer polarization between the NV and the pair of electron spins. These results demonstrate a key step towards full quantum control of electronic spin registers in room temperature solids.
@article{arxiv.1801.00198,
title = {Sensing coherent dynamics of electronic spin clusters in solids},
author = {Emma L. Rosenfeld and Linh M. Pham and Mikhail D. Lukin and Ronald L. Walsworth},
journal= {arXiv preprint arXiv:1801.00198},
year = {2018}
}