/library/oar/handle/123456789/82071 2026-06-16T22:31:42Z /library/oar/handle/123456789/82128 Title: Dielectric properties of standard liquids at hyperbaric pressures Abstract: Knowledge of the dielectric properties of a given material is essential for the characterization of its interaction with an electromagnetic field. To date, all dielectric property measurements on liquids have been reported at atmospheric pressure. Water-based liquid solutions contain dissolved gases (mostly oxygen and nitrogen), the concentration of which increases with the pressure of the overlying air. This is bound to affect the dielectric properties. The aim of this project is to devise a method for carrying out dielectric measurements over a wide frequency range as a function of pressure. This study could potentially lead to dielectric measurements on human blood under pressure, and hopefully result in establishing a direct relationship of the complex permittivity of blood with the concentration of dissolved nitrogen. An in-house designed and constructed high pressure vessel was used and measurements were carried out on distilled water, 0.1M NaCl, Propan-2-ol, Acetone and Triton X-100. A Vector Network Analyser (VNA) connected with an open-ended coaxial probe was used to carry out measurements on the liquid under test inside the air tight vessel. A three step calibration (open, short, load) was used with 0.1M NaCl used as a reference liquid for validation. The results were compared to published dielectric parameters obtained at atmospheric pressure. The most significant change was observed for relative permittivity of distilled water which exhibited an average increase of around 4%. The loss factor did not exhibit any significant change. Similar behaviour was observed in 0.1M NaCl. Solutions with relatively low dielectric properties (Propan-2-ol, Acetone and TX-100) did not undergo any significant changes as the overlying air pressure was increased. However, experimental limitations due to the limited surface area in the pressure vessel might have limited any significant changes. Thus, a modified pressure system could be used to obtain better characterisation of the dielectric properties as a function of pressure. Description: B.Sc. (Hons)(Melit.) 2021-01-01T00:00:00Z /library/oar/handle/123456789/82125 Title: The thermodynamics of one qubit Abstract: ¸£ÀûÔÚÏßÃâ·Ñ processes are fundamentally physical. One cannot shy away from the fact that when executing an algorithm on a quantum computer, one is seeing a hamiltonian play out it front of their eyes. Maxwell, Gibbs, Szilard, Landauer [1, 2, 3, 4] and others have all shown in different ways that changes in the distribution of information in a system have thermodynamic repercussions. Since, quantum systems are arguably the richest in terms of their information structures, the resulting thermodynamics must be equally rich. This is a mysterious area, as is epitomised by the black hole information paradox, but developments in recent years [5] are starting to show paths towards understanding. In the research presented in this dissertation, a small step down where these paths lead is taken. The lofty goal of understanding the thermodynamics of quantum information processes is transformed into an examination of a specific and smaller instance, examining the thermodyanmics of the DQC1 circuit [6] via its entanglement. A problem which ultimately revolves around the quantification of multipartite entanglement. The intent of this document is for the reader to be able to understand the problem of multipartite entanglement quantification, how entanglement is closely related to thermodynamics and the research carried out by the author in this space. To do so I will begin in the first chapter by introducing the landscape of quantum mechanics after which I will zoom in on the sub-field of quantum information, introducing all the tools needed for the research carried out. After this, I delve into the research problem of quantifying the entanglement of the DQC1 circuit towards making use of Huber et al’s relationship between entanglement and thermodynamic work [7]. Describing the solution to this challenge and how this led to an understanding of the minimal thermodynamics of this algorithm. Lastly, I speak of the implications of this work, the importance of understanding the thermodynamics of quantum algorithms and improving our methods of entanglement quantification as well as future work. Description: B.Sc. (Hons)(Melit.) 2021-01-01T00:00:00Z /library/oar/handle/123456789/82124 Title: In-vivo dielectric properties of the human oral cavity at microwave frequencies Abstract: The aim of this investigation was to study the interaction between low-power electromagnetic fields and different tissues within the oral cavity, given by the complex permittivity. In recent years, there have been many research efforts to use electromagnetic fields for medical applications and up-to date different diagnostic and therapeutic modalities in dentistry use ionising radiation, mostly X-rays. This project addresses gaps in knowledge required to develop novel microwave medical devices for diagnosis for imaging and treatment of mouth lesions such as tumours by conducting measurements of the complex permittivity. In particular, this study reports on the in-vivo dielectric measurements of six different areas in the oral cavity, mainly the dorsal (upper-surface of the tongue), ventral (lower surface of the tongue), left and right sides, the tip of the tongue and lips. A rigorous measurement procedure was implemented and in-vivo measurements were conducted on 25 patients from different age groups. It has been observed that even though in dentistry different areas are used to distinguish between different parts of the tongue, there exist no difference in the dielectric data of these different areas. In fact, no dielectric difference was established when comparing ventral and dorsal tissues, left and right sides, and tip and thus the dielectric properties of the tongue can be referenced by one value, calculated by considering a grouped average of the different areas. Additionally, the incidence of different clinical conditions in the oral cavity depends mostly on age of patients, smoking/non-smoking and gender. In this study, the dielectric data was analysed for different patient ages and it was observed that there exists a difference between the dielectric data measured for 40-50 years age group and the 60+ years age group. The latter have higher complex permittivity for tongue, but lower values for lips. The complex permittivity for lips of 20-30 years age group was lower when compared to other age groups. This can be attributed to the extremely low values of two patients having different ethnicity in the group. A study with a larger is planned to better understand the correlation of dielectric data with the various confounders. Description: B.Sc. (Hons)(Melit.) 2021-01-01T00:00:00Z /library/oar/handle/123456789/82122 Title: Crossover between open systems dynamical regimes Abstract: In the past few decades rapid progress has been made in the study of open quantum systems, leading to the development of a wide variety of quantum technologies as well as experiments. All such applications of quantum physics are subject to unwanted interactions with the external environment which destroy or inhibit the quantum resources they depend on, limiting their usefulness and scalability. One of the most useful phenomena in open quantum systems is non-Markovianity, which is the revival of the initial conditions which allows one to recover quantum resources after interaction with the environment. In this dissertation we study non-Markovian effects using quantum spin chains. In particular we study the additivity properties of the Breuer-Laine-Piilo (BLP) measure of non-Markovianity and show that it is subadditive for the studied model. We also find the initial states which maximise the BLP measure for a single chain and two uncorrelated chains. Description: B.Sc. (Hons)(Melit.) 2021-01-01T00:00:00Z