A compact ion-trap quantum computing demonstrator

Quantum information processing is steadily progressing from a purely academic discipline towards applications throughout science and industry. Transitioning from lab-based, proof-of-concept experiments to robust, integrated realizations of quantum information processing hardware is an important step in this process. However, the nature of traditional laboratory setups does not offer itself readily to scaling up system sizes or allow for applications outside of laboratory-grade environments. This transition requires overcoming challenges in engineering and integration without sacrificing the state-of-the-art performance of laboratory implementations. Here, we present a 19-inch rack quantum computing demonstrator based on $^{40}\textrm{Ca}^+$ optical qubits in a linear Paul trap to address many of these challenges. We outline the mechanical, optical, and electrical subsystems. Further, we describe the automation and remote access components of the quantum computing stack. We conclude by describing characterization measurements relevant to digital quantum computing including entangling operations mediated by the Molmer-Sorenson interaction. Using this setup we produce maximally-entangled Greenberger-Horne-Zeilinger states with up to 24 ions without the use of post-selection or error mitigation techniques; on par with well-established conventional laboratory setups

Model-based controller design for a lift-and-drop railway track switch actuator

Track switches are essential in order to enable railway vehicles to change routes however they are also the largest single cause of failure on the railway network. A new generation of switching concepts are emerging from projects like In2Rail, REPOINT and S-Code that promise to improve rail network performance through the use of new mechanisms, monitoring and control systems. This paper focusses on modelling and control of a lab-demonstrator from the REPOINT project. Unlike conventional track switch machines, this actuator needs closed loop feedback control. First, a detailed simulation model of the actuator is developed and validated against experimental results. Two model-based control designs are then developed and tested: a classical cascaded P/PI controller and a modern state feedback controller. The two controllers are compared and it is found that, whilst there are some performance differences, both meet the requirements for use in a redundantly actuated REPOINT switch

Electrical fault management orientated design of future electrical propulsion aircraft

Electrical propulsion aircraft (EPA) have been cited as the future of aviation, enabling greener, quieter, more efficient aircraft. However, due to the stringent requirements surrounding aircraft certification, these novel EPA concepts will need to demonstrate high levels of safety and reliability if electrified flight is ever to become a mainstream mode of passenger transportation. Therefore, robust electrical fault management (FM) is necessary to maintain critical levels of aircraft thrust and to enable high confidence in the reliability and safety of future EPA designs. To date, electrical FM for EPA has been done at a first-pass, minimal level or not at all. For electrical FM to be effective, it must be integrated into the aircraft design from an early stage. This dictates that a novel approach to the design of electrical architectures for EPA is required which addresses the current uncertainty in the availability of suitable FM technologies for future EPA electrical architectures. Therefore, a first-of-kind FM strategy map is presented which identifies projections on the progression of key areas of future EPA-specific FM technology development and acts as a pre-cursor to future FM technology roadmaps. Furthermore, the FM orientated early-stage electrical architecture design methodology presented in this thesis derives feasible, FM-capable electrical architectures for a given EPA concept and captures significant assumptions which impact the down selection process. Since any novel EPA electrical architecture will require some form of testing in hardware, a novel framework for strategic FM demonstrator development is then proposed and the FM test goals for different levels of demonstrator are identified. This strategic development of critical aspects of FM and early integration of FM requires a portfolio of FM demonstrators and test beds for EPA and is crucial if unproven, future EPA electrical architectures are to reach high confidence.Electrical propulsion aircraft (EPA) have been cited as the future of aviation, enabling greener, quieter, more efficient aircraft. However, due to the stringent requirements surrounding aircraft certification, these novel EPA concepts will need to demonstrate high levels of safety and reliability if electrified flight is ever to become a mainstream mode of passenger transportation. Therefore, robust electrical fault management (FM) is necessary to maintain critical levels of aircraft thrust and to enable high confidence in the reliability and safety of future EPA designs. To date, electrical FM for EPA has been done at a first-pass, minimal level or not at all. For electrical FM to be effective, it must be integrated into the aircraft design from an early stage. This dictates that a novel approach to the design of electrical architectures for EPA is required which addresses the current uncertainty in the availability of suitable FM technologies for future EPA electrical architectures. Therefore, a first-of-kind FM strategy map is presented which identifies projections on the progression of key areas of future EPA-specific FM technology development and acts as a pre-cursor to future FM technology roadmaps. Furthermore, the FM orientated early-stage electrical architecture design methodology presented in this thesis derives feasible, FM-capable electrical architectures for a given EPA concept and captures significant assumptions which impact the down selection process. Since any novel EPA electrical architecture will require some form of testing in hardware, a novel framework for strategic FM demonstrator development is then proposed and the FM test goals for different levels of demonstrator are identified. This strategic development of critical aspects of FM and early integration of FM requires a portfolio of FM demonstrators and test beds for EPA and is crucial if unproven, future EPA electrical architectures are to reach high confidence