A neutral nitrogen-vacancy center (NV0) is promising for realizing strong coupling with a single microwave photon due to its large electric field sensitivity, although it is susceptible to environmental phonon noise at 5 K. Decreasing the temperature to 15 mK results in a tenfold increase in orbital relaxation time compared to that at 5 K. Dynamical decoupling pulses significantly increase the orbital coherence time to around 1.8 μs, representing a 30-fold improvement compared to that without decoupling pulses. Based on these results, a single NV0 can reach the strong coupling regime when coupled with a high-impedance microwave resonator, thus opening up the possibility of microwave quantum electrodynamics using a single optically-active defect center in diamond.
@article{arxiv.2411.17187,
title = {Quantum Orbital-State Control of a Neutral Nitrogen-Vacancy Center at Millikelvin Temperatures},
author = {Hodaka Kurokawa and Shintaro Nakazato and Toshiharu Makino and Hiromitsu Kato and Shinobu Onoda and Yuhei Sekiguchi and Hideo Kosaka},
journal= {arXiv preprint arXiv:2411.17187},
year = {2026}
}