Improving gate fidelities for laser-written nitrogen vacancy centres in diamond membranes

If a quantum computer could be built with enough qubits, it would be able to solve problems that are intractable with the classical computers we have now. A leading design for this is to build nodes with five or more interacting qubits, and then link up many of these nodes. Nitrogen vacancy centres (NVC) in diamond at cryogenic temperatures have been used to demonstrate this linking by entangling their electron spins optically. The nuclear spins coupled to NVC can have long coherence times of over 10 seconds.
This project will make use of our laser-written NVC and the laser-written electrical wires we can create around them [1, 2]. The laser writing is done by the group of our collaborator Patrick Salter in Oxford University. We will build arrays of these qubits inside diamond membranes so that the diamonds can be put into optical cavities in the group of Jason Smith in Oxford. We will measure spin coherence times and improve the fidelity of the spin control. Initial experiments will be at room temperature, but cryogenic measurements will be used also as this is needed to entangle two NVC.
We collaborate with Jason Smith's group in Oxford, Element Six and Oxford Instruments Plasma Technology as part of the UK National Quantum Computation and Simulation (QCS) Hub. This PhD studentship is funded by the EPSRC through this Hub.