Robust Quantum Information Processing using Quantum Spin Networks

Future quantum devices are powerful devices that will generally generate, manipulate,
and store quantum information using qubits. A linear array of solid-state
types of qubits (known as spin chains) have been thoroughly investigated. It has
demonstrated its usefulness for short-range quantum communication and computation,
and entanglement generation. In this thesis, we design complex Spin
Network (SN) systems by coupling together spin chain systems using a novel unitary
transformation method. The richer topology involved in our SN systems gives
wider application than spin chains and enables the generation of various quantum
information processing without the need to re-engineer the SN parameters, such
as coupling interactions, for each unique task. We have used the SN for routing
quantum information, generating various types of entangled states, and for
quantum sensing purposes. All these applications have been investigated against
different types of disorder and show very good robustness for practical levels of
disorder. Investigation of the scalability of the SN by increasing the number of
qubits or by increasing the number of spin chains that form the SN have also been
considered. As the SN description and approach are widely applicable to a range
of physical realisations, our work demonstrates the feasibility of realising these
quantum information systems as practical devices