Detecting and controlling spin pairs near NV centres in diamond

The development of quantum computers is a monumental challenge for modern physics. One proposed pathway toward a fully scalable and fault-tolerant quantum computer involves the development of a quantum network. Such a network would have applications ranging from distributed quantum computation to fundamentally secure quantum communication. The building blocks of such a network, the nodes, require optical links with which to generate entanglement with other nodes, as well as memory and data qubits to improve the entanglement between nodes and perform computations. In this thesis, we study the dynamics of spin pairs surrounding nitrogen-vacancy(NV) centres in diamond - a promising proposed node for a quantum network. We build on previous work that has successfully detected and controlled pairs of strongly coupled 13C nuclear spins using the NV centre as a probe, and investigate how these spin pairs can be individually addressed using radio frequency pulses.Next, we consider pairs of P1 centres and demonstrate the detection and control of the electron spins of this pair. We show that dynamical decoupling sequences can be used to initialise and readout the electron pair of the P1 centres with high fidelity (∼94 − 96%), and measure natural dephasing times of ∼ 50 ms with the NV centre in the m s = 0 state. The control we demonstrate over pairs of electron spins in P1 centres is an important proof-of-concept that electronic spin defects in diamond can be coherently controlled, and used as memory or data qubits in a future quantum network node.Applied Physic