Optically addressable universal holonomic quantum gates on diamond spins

Abstract

The ability to individually control the numerous spins in a solid solid-state crystal is essential technology for the development of large-scale quantum processors and memories. Localized laser field offers spatial selectivity for electron spin manipulation through spin-obit coupling. However, it has been difficult to simultaneously achieve the precise and universal manipulation by itself. Here, we demonstrate microwave-driven holonomic quantum gates on an optically selected electron spin in a nitrogen-vacancy (NV) center in diamond. The electron spin is precisely manipulated with global microwave tuned to the frequency shift induced by the local optical Stark effect. We show the universality of the operations, including state initialization, preparation, readout, and echo. We also generate optically addressable entanglement between the electron and adjacent nitrogen nuclear spin, thus satisfying the scalability requirement of qubits. High fidelity operations are achieved by applying amplitude-alternating pulses, which are tolerant to fluctuations in microwave intensity and detuning. These techniques enable site-selective quantum teleportation transfer from a photon to a nuclear spin memory, paving the way for the realization of distributed quantum computers and the quantum Internet with large-scale quantum storages. Main text I.

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“…With the microwave field tuned to one of the resonances, ω mw /2π = 3.00 GHz, measurements following the pulse sequence shown in the inset of Figure b produce Rabi oscillations at Ω i /2π = 7.5 MHz. We next apply this spin control to Ramsey fringe (Figure c) and Hahn echo (Figure d) measurements, yielding coherence times for this spin memory of T 2 * = 1.7 μs and T 2 = 150 ± 5 μs, typical for NV spins in diamond nanostructures. − For the remainder of the measurements in this paper, we consider only the NV subpopulation corresponding to the feature at 3.00 GHz in Figure a and set ẑ along the corresponding dipole axis.…”