Quantum control and engineering of single spins in diamond

V. V. Dobrovitski

D. D. Awschalom

Takashi Yamamoto, H. Benjamin van Ommen, Kai-Niklas Schymik +7 more

Solid-state spin defects are a promising platform for quantum networks. A key requirement is to combine long ground-state spin-coherence times with a coherent optical transition for spin-photon entanglement. Here, we investigate the spin and optical coherence of single nitrogen-vacancy (NV) centres in (111)-grown isotopically engineered diamond. Our diamond-growth process yields a precisely controlled $^{13}\mathrm{C}$ concentration and low-ppb nitrogen concentrations. Combined with the mitigation of 50 Hz noise using a real-time feedforward scheme and tailored decoupling sequences, this enables record defect-electron-spin coherence times of $T_2 = 6.8(1)$ ms for a Hahn echo and of $T_2^{DD} = 11.2(8)$ s under dynamical decoupling. In addition, we observe coherent optical transitions with a near-lifetime-limited homogeneous linewidth of 16.9(4) MHz and characterize the spectral diffusion dynamics. These results provide new avenues to investigate the incorporation of impurities in diamond and new opportunities for improved spin-qubit control for quantum networks and other quantum technologies.

Joseph P. Heremans

Nathalie P. de Leon

Recently, there has been intense activity in developing diamond as a quantum platform, driven by the discovery of defects that can be addressed optically and have long spin coherence times, enabling quantum control using optical microscopy. I will describe materials engineering efforts to control and explore these systems.

Mikhail D. Lukin

We will discuss our recent work on developing new approaches for quantum control of single spins and single photons in diamond. Novel applications of these techniques to realization of quantum repeaters and nanoscale magnetic sensing will be described.