Schemes for robust quantum information processing using photons

Abstract

The advent of quantum technologies looks poised to make a significant impact on a wide variety of scientific and technological fields. Quantum computing, communications, and sensing, are wellknown to offer performance that cannot be matched by classical methods. Over the last twenty years, they have been transformed from scientific curiosities and theoretical models, to mature, well-developed technologies, by a global research effort. Among these, quantum computing offers a paradigmatic shift in computational power, but requires the coherent control of millions of quantum information carriers. The use of photons offers a route to scalable quantum technologies, provided imperfections in physical systems can be adequately mitigated. In this thesis, we present schemes to process quantum information reliably in the presence of errors. A fault-tolerant quantum computing architecture is presented based on linear optics and quantum emitters, and we analyse its performance under realistic operating conditions. We present a comprehensive framework for measuring physical systems in the presence of loss errors, and investigate the advantages of such an approach when applied to different quantum technologies. Then, we introduce and examine a novel, resource-efficient protocol for the generation of high-dimensional entangled states from non-interacting quantum emitters. Finally, we tackle the decoding problem in quantum error correction by introducing a local decoder for fault-tolerant quantum computing in the measurement-based setting.

Date of Award	8 Jan 2025
Original language	English
Awarding Institution	University of Bristol
Supervisor	Dara P S McCutcheon (Supervisor) & Anthony Laing (Supervisor)