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.