Optical holonomic single quantum gates with a geometric spin under a zero field

By Y. Sekiguchi, Naeko Niikura, Ryota Kuroiwa, Hiroki Kano, H. Kosaka. Nature Photonics, 2017

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The realization of fast fault-tolerant quantum gates on a single spin is the core requirement for solid-state quantum-information processing. As polarized light shows geometric interference, spin coherence is also geometrically controlled with light via the spin–orbit interaction. Here, we show that a geometric spin in a degenerate subspace of a spin-1 electronic system under a zero field in a nitrogen vacancy centre in diamond allows implementation of optical non-adiabatic holonomic quantum gates. The geometric spin under quasi-resonant light exposure undergoes a cyclic evolution in the spin–orbit space, and acquires a geometric phase or holonomy that results in rotations about an arbitrary axis by any angle defined by the light polarization and detuning. This enables universal holonomic quantum gates with a single operation. We demonstrate a complete set of Pauli quantum gates using the geometric spin preparation and readout techniques. The new scheme opens a path to holonomic quantum computers and repeaters. Ground-state spin rotations in a nitrogen–vacancy centre in diamond are manipulated within nanoseconds of a near-resonant light field being applied. Pauli quantum gates are demonstrated using the geometric spin preparation and read-out techniques.

Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/17b01c22c4c02d6b22a7022dcb566d7235e0f62e