/library/oar/handle/123456789/63157 Wed, 10 Jun 2026 13:45:32 GMT 2026-06-10T13:45:32Z /library/oar/handle/123456789/73722 Title: Topological transport and quantum estimation theory in optomechanical systems Abstract: This thesis focuses on optomechanics, which is the physical description of the force that the electromagnetic radiation exerts on a reflective object. The particles involved are so tiny that a quantum mechanical description is needed. Optomechanics is the median force between a quantum mechanical oscillator and a quanta of light. Hence, it has the potential to assume a major role in future technologies. Quantum transport has been extensively studied in the last few decades, and still offer an important substrate for emerging technologies. In this thesis we studied quantum transport and applied it to a one dimensional system of both bosonic and fermionic particles. We obtained quasi perfect many body transfer. One hurdle from obtaining perfect transfer is due to the opposite possible directions of propagation inside the system. A way to overcome this issue is offered by means of topological insulators, materials which allow unidirectional propagation. We aim to exploit optomechanics in order to transport excitations in a robust way. We engineered an array of microresonators which has the property of a topological insulator and where the mechanical motion spreads into the material in one way only. From an experimental point of view, the realization of this kind of mechanical topological insulator requires a good knowledge of the optomecanical coupling strength. Therefore we used quantum estimation theory to understand which is the best measurement that will lead to an optimal estimation of the optomechanical coupling constant. This will play an important role for cutting-edge technology and applications in communication, phonon-based information storage and signal-processing devices. Description: PH.D.PHYSICS Wed, 01 Jan 2020 00:00:00 GMT /library/oar/handle/123456789/73722 2020-01-01T00:00:00Z /library/oar/handle/123456789/63752 Title: A long-range data-link for real-time, drone-based antenna pattern measurements Abstract: The antenna pattern is an important feature associated with antennas that gives information about the device’s radiative properties. It is then important to be able to characterise this pattern, for a given antenna, at a distance that is representative of its application. For most antennas, this distance would lie in the far-field. The far-field for large antennas, as are radio telescopes, has quite a far-reaching lower bound, rendering traditional methods inadequate. The introduction of drones mitigates the main problems of these methods since they possess inherent maneuverability. A means of communication between the drone and a ground station is now required for the transmission of data, namely, drone telemetry. In this project, such a data link operating on the radio band is developed. Apart from the development of custom software, considerations regarding different antennas used by the data link at either end were carried out to extend the range. Description: B.SC.(HONS)MATHS&PHYSICS Wed, 01 Jan 2020 00:00:00 GMT /library/oar/handle/123456789/63752 2020-01-01T00:00:00Z /library/oar/handle/123456789/63751 Title: The night sky brightness of Gozo Abstract: The aim of this project was to carry out Night Sky Brightness measurements in Gozo, with a view to comparing with data collected between 2017 and 2018. Current studies have shown that light pollution is on the increase. This has adversely affected the night sky and carries implications for ecology and human health. This study assessed the situation in Gozo, and from the collected data it emerges that while some areas exhibit a decrease in night sky brightness, there are still major increases in 33.3% of the island. In addition to island-wide measurements, further data at higher resolution were collected at the site of Dwejra, a designated Dark Sky Heritage Area (DSHA), Special Area of Conservation (SAC) of International Importance, and Natura 2000 site. Description: B.SC.(HONS)MATHS&PHYSICS Wed, 01 Jan 2020 00:00:00 GMT /library/oar/handle/123456789/63751 2020-01-01T00:00:00Z /library/oar/handle/123456789/63750 Title: Decoherence effects on quantum information processing protocols Abstract: Noisy Intermediate-Scale Quantum computers (NISQ) are fervently accelerating the capacity of Quantum ����������� Processing (QIP) tasks. The launch of the IBM Quantum Experience (IBM-QE) provided publicly available NISQ processors that can be accessed remotely. Apart from performing quantum computation, IBM-QE processors have been able to successfully simulate many quintessential open quantum system models. Nevertheless, decoherence is a pressing issue in QIP, as noise generated during quantum computation effectively destroys encoded quantum information. The primary objective of this work is to analyse the effects of decoherence on QIP protocols, by simulating quantum teleportation and secret sharing protocols in an open quantum systems scenario on IBM-QE processors. It is demonstrated that implementing a phase damping channel acting on the entangled quantum state utilised in the teleportation process, by means of a collisional model, results in the decay of entanglement, diminishing the state’s capability as a quantum resource. It is also shown that decoherence resulting from the inherent dephasing and thermal relaxation processes occurring during quantum computation, is indeed amplified by increasing circuit depth. Description: B.SC.(HONS)MATHS&PHYSICS Wed, 01 Jan 2020 00:00:00 GMT /library/oar/handle/123456789/63750 2020-01-01T00:00:00Z