Geometric manipulation with polarized microwaves over an electron and a nuclear spin in diamond

Lilian Childress

Lilian Childress

Yuhei Sekiguchi

M. V. Gurudev Dutt, Lilian Childress, Liang Jiang +6 more

The key challenge in experimental quantum information science is to identify isolated quantum mechanical systems with long coherence times that can be manipulated and coupled together in a scalable fashion. We describe the coherent manipulation of an individual electron spin and nearby individual nuclear spins to create a controllable quantum register. Using optical and microwave radiation to control an electron spin associated with the nitrogen vacancy (NV) color center in diamond, we demonstrated robust initialization of electron and nuclear spin quantum bits (qubits) and transfer of arbitrary quantum states between them at room temperature. Moreover, nuclear spin qubits could be well isolated from the electron spin, even during optical polarization and measurement of the electronic state. Finally, coherent interactions between individual nuclear spin qubits were observed and their excellent coherence properties were demonstrated. These registers can be used as a basis for scalable, optically coupled quantum information systems.

Yuhei Sekiguchi, Kazuki Matsushita, Yoshiki Kawasaki +1 more

Abstract Spins in diamond are ideal for 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 amplitude-alternating pulse, 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 storage.

Koyo Kuramitani