This thesis collects my own and collaborative work I have been involved with finding localised systems in quantum field theory that are be useful for quantum information. It draws from many well established physical theories such as quantum field theory in curved spacetimes, quantum optics and Gaussian state quantum information. The results are split between three chapters. For the first results, we set-up the basic framework for working with quantum fields confined to cavities. By considering the real Klein-Gordon field, we describe how to model the non-uniform motion of a rigid cavity through spacetime. We employ the use of Bogoliubov transformations to describe the effects of changing acceleration. We investigate how entanglement can be generated within a single cavity and the protocol of quantum teleportation is affected by non-uniform motion. The second set of results investigate how the Dirac field can be confined to a cavity for quantum information purposes. By again considering Bogoliubov transformations, we thoroughly investigate how the entanglement shared between two cavities is affected by non-uniform motion. In particular, we investigate the role of the Dirac fields charge in entanglement effects. We finally analyse a \one-way-trip" of one of the entangled cavities. It is shown that different types of Dirac field states are more robust against motion than others. The final results looks at using our second notion of localisation, Unruh-DeWitt detectors. We investigate how allowing for a \non-point-like" spatial profile of the Unruh-DeWitt detector affects how it interacts with a quantum field around it. By engineering suitable detector-field interactions, we use techniques from symplectic geometry to compute the dynamics of a quantum state beyond commonly used perturbation theory. Further, the use of Unruh-DeWitt detectors in generating entanglement between two distinct cavities will be investigated.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:594673 |
| Date | January 2013 |
| Creators | Lee, Antony Richard |
| Publisher | University of Nottingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://eprints.nottingham.ac.uk/13624/ |
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