Quantum interference in universal linear optical devices for quantum computation and simulation

It is believed that the exotic properties of quantum systems can be harnessed to perform certain computational tasks more efficiently than classical theories allow. The production, manipulation and detection of single photons constitutes a potential platform for performing such non-classical information processing. The development of integrated quantum photonics has provided a miniaturised, monolithic architecture that is promising for the realisation of near-term analog quantum devices as well as full-scale universal quantum computers. In this thesis we investigate the viability of these photonic quantum computational approaches from an experimental and theoretical perspective. We implement the first universally reconfigurable linear optical network; a key capability for the rapid prototyping of photonic quantum protocols. We propose and demonstrate the use of these devices as a new platform for the programmable quantum simulation of molecular vibrational dynamics. We then tackle an important outstanding problem in linear optical quantum computing; quantifying how partial-distinguishability amongst photons aff ects logical error rates. Finally, we propose a series of schemes aimed at counteracting these distinguishability errors in order to achieve practical quantum technologies with imperfect photonic components.Open Acces