Scalable defect-based solid-state quantum devices

• Speaker: Lee, Sangyun (Center for Quantum Information, Korea Institute of Science and Technology)

Electronic and nuclear spins in solids can form hybrid quantum registers in which electronic spins are ancillary qubits for initialization and readout of nuclear spins that are physical qubits. Their long lifetime and coherence time, exceeding 1 second, and efficient coherent control by magnetic resonance techniques allow for realizing small scale quantum registers [1,2]. In some crystalline solids, the fluorescence properties of point defects can be correlated with electronic spins with high fidelity, thus “artificial atoms” provide quantum links via photonic quantum networks among quantum nodes [2,3]. Such a photonic network may open a pathway towards modular structured quantum information processing devices. However, there exist bottlenecks such as better control of spin-spin interaction and improving spin-to-photon interface efficiency. In this talk, I’ll introduce our progress towards small-scale quantum nodes consisting of coupled electron spin pairs and nuclear spins in diamond, and efficient photonic control using photonic structures such as cone-shaped diamond nano-antenna. Also, recent results from new candidates in wide-bandgap semiconductors will be introduced [1,4,5].

[1] M. Atatüre, D. Englund, N. Vamivakas, S.-Y. Lee, and J. Wrachtrup, Nat. Rev. Mater. 3, 38 (2018).

[2] D. D. Awschalom, R. Hanson, J. Wrachtrup, and B. B. Zhou, Nat. Photonics 12, 516 (2018).

[3] P. C. Humphreys, N. Kalb, J. P. J. Morits, R. N. Schouten, R. F. L. Vermeulen, D. J. Twitchen, M. Markham, and R. Hanson, Nature 558, 268 (2018).

[4] R. Nagy, M. Niethammer, M. Widmann, Y.-C. Chen, P. Udvarhelyi, C. Bonato, J. Hassan, R. Karhu, I. Ivanov, N. T. Son, J. Maze, O. Taekshi, Ö. Soykal, A. Gali, S.-Y. Lee, F. Kaiser, and J. Wrachtrup, ArXiv:1810.10296 (2018).

[5] P. Udvarhelyi, R. Nagy, F. Kaiser, S.-Y. Lee, J. Wrachtrup, and A. Gali, ArXiv Prepr. ArXiv1811.02037 (2018).