Understanding and overcoming the barriers to room-temperature quantum computation in diamond

NV spin clusters in diamond, consisting of NV centres coupled to nearby nuclear spins, form one of the few platforms suitable for room-temperature quantum computing. We present an overview of our work on understanding and overcoming the barriers for large scale quantum computation with NV spin clusters: (1) A critical limit on qubit initialisation and readout fidelities is nuclear relaxation induced by the NV electron flipping between its ground and optically excited states. Certain lattice sites are relatively immune to this effect. We perform ab initio modelling of the NV optical-spin dynamics to estimate gate fidelities for different ¹³C sites. (2) The density of nuclear spin resonances in NV spin clusters requires careful design of control pulses to avoid erroneous driving of qubits. We are designing fast pulses that minimise erroneous driving, using both analytical and numerical techniques. (3) The major barrier to scalable diamond quantum computing remains on-chip networking of NV spin clusters. We have recently proposed a new approach, and our follow-up modelling has shown that nanowires should be able to guide coherent electron transport between defects. We have also identified possible quantum transport techniques with the potential to greatly enhance transport fidelity.