Localised Systems in Relativistic Quantum Information

Abstract

This thesis collects my own and collaborative work I have been involved with finding localised systems in quantum field theory that are 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. 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. It is shown that different types of Dirac field states are more robust against motion than others. The final results look 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. There is also a conclusions chapter at the end of the thesis which summarises the results presented and suggestions of possible new directions of research in relativistic quantum information are made.

v2 PhD thesis, 227 pages, 16 figures

References in corpus (33)

• Quantum computing with trapped ions
• The Unruh effect and its applications
• Quantum teleportation using active feed-forward between two Canary Islands
• LQG vertex with finite Immirzi parameter
• Entanglement of Dirac fields in non-inertial frames
• Quantum Entanglement of Moving Bodies
• Generating Entangled Microwave Radiation Over Two Transmission Lines
• Phase analysis of quantum oscillations in graphite
• Efficient Teleportation between Remote Single-Atom Quantum Memories
• The dynamical Casimir effect in superconducting microwave circuits
• Path Entanglement of Continuous-Variable Quantum Microwaves
• Tunable coupling in circuit quantum electrodynamics with a superconducting V-system
• Fermionic mode entanglement in quantum information
• Entanglement and purity of two-mode Gaussian states in noisy channels
• A superconducting qubit with Purcell protection and tunable coupling
• Entanglement between the future and past in the quantum vacuum
• Relativistic Quantum Teleportation with Superconducting Circuits
• Redistribution of particle and anti-particle entanglement in non-inertial frames
• Equivalence between Entanglement and the Optimal Fidelity of Continuous Variable Teleportation
• Thermal time and the Tolman-Ehrenfest effect: temperature as the "speed of time"
• Time evolution techniques for detectors in relativistic quantum information
• Particle and anti-particle bosonic entanglement in non-inertial frames
• Fermionic entanglement that survives a black hole
• Entangling moving cavities in non-inertial frames
• Static, stationary and inertial Unruh-DeWitt detectors on the BTZ black hole
• Fermionic entanglement ambiguity in non-inertial frames
• Table-top creation of entangled multi-keV photon pairs via the Unruh effect
• Optimal fidelity of teleportation of coherent states and entanglement
• Quantum gates and multipartite entanglement resonances realized by non-uniform cavity motion
• Quantum teleportation between moving detectors
• Spatially extended Unruh-DeWitt detectors for relativistic quantum information
• Relativistic Quantum Information: developments in Quantum Information in general relativistic scenarios
• Probing the spacetime structure of vacuum entanglement