VictorJuiz/thesis huggingface dataset:
Experimental entanglement distillation of continuous-variable optical states
Keywords: entanglement
photonics
Quantum optics

Entangled photons are ideally suited to the transmission of photonic quantum information. Mitigating the effects of decoherence is fundamental to distributing photonic entanglement across large distances. One such proposal is entanglement distillation, in which operations on a large ensemble of weakly entangled states generate a smaller ensemble of more strongly entangled states.
In this thesis, we experimentally and theoretically analyse various tools required for demonstrating continuous-variable (CV) entanglement distillation, following the proposal by Browne et al., [Phys. Rev. A 67, 062320 (2003)]. Specifically, we propose figures of merit to account for the practical limitations of non-deterministic non-Gaussian operations, and analyse the experimental parameters necessary to optimise them. We develop a source of pulsed two-mode squeezed states, which are the initial states of our entanglement distillation protocol. We use weak-field homodyne detection as a phase-dependent photon counting detector, and demonstrate its utility in conditional state generation. Using these states, we demonstrate sub-binomial light as a tool for benchmarking quantum states. Finally, we applied two-mode weak-field homodyne detection to two entangled states and demonstrate correlations in the photon counting statistics which depend on a joint phase from two independent local oscillators. This setup is sufficient to apply an entanglement witness developed by Puentes et al. [New J. Phys. 12, 033042 (2010)]. Despite encouraging simulations, we do not witness entanglement with this scheme, which we attribute to a noise source unaccounted for in the simulations.
Although we do not demonstrate entanglement distillation outright, the tools we develop to do so represent a general, hybrid approach to CV quantum optics. Developing tools such as phase-resolved projective measurement on two-mode states allows us to probe both the wave and particle nature of entangled light at the single-photon level. Using and expanding these techniques to probe larger quantum systems may prove useful in studies of fundamental physics and quantum enhanced technologies.
The political economy of technological change, energy and climate change
Keywords: economics
climate change
politics
Technology
energy

This thesis sets out to explore some of the key dimensions in the process of socio-technological change inherent in the shift to a low carbon economy. This is done in two parts, the first focusing on theory, the second, empirical case studies. Out of the diversity of interactions between actors, technologies, and policies surrounding this process, one key question emerges: can societies really shift the structure of their economies so fundamentally to achieve a low carbon future within a reasonable timeframe? Chapter One develops an integrated approach to economic and political change to interrogate this question. This synthesizes a review of literature (Part One) examining the role of technology within some of the main theories of economic change in the social sciences. Two broad paradigms are distinguished. First, a paradigm based around the notion of equilibrium, notably the standard welfare approach of neoclassical economics; and secondly, an evolutionary paradigm, which views the economy as a complex adaptive system – such as exemplified by theories of path dependency. This theoretical background provides a broad narrative to frame and inform Part Two of the thesis. First in Chapter Four, socio-technical change is investigated in the context of the diffusion of energy efficient lighting in Germany. This study investigates the relationships between human behaviour and attitudes, lamp technology and the evolving nature of institutions, to provide a framework with which to consider the contentious issue of individual freedom versus government control in the politics of change to lower-carbon emissions. In Chapter Five, the case for the creation of a market for CO2 pollution permits is developed. In making this case, the strengths and weaknesses of emissions trading are compared and contrasted with other policy instruments and the broader political economy of the various policy options discussed. Chapter 6 builds on this to examine the political economy of implementing an emissions trading scheme in Australia and the impact the Kyoto Protocol has had on domestic politics and GHG mitigation. Chapter Seven continues with the theme of building ‘a political ecology of the state’ by investigating the politics and economics of greenhouse gas mitigation in Russia. Finally, Chapter Eight recapitulates the aims, nature and conclusions of this research and draws out its implications for policy as well as mapping out some areas for further research. In particular, the need to bring a greater sense of politics back into the study of the economy is highlighted as a vital part of building a renewed, more sustainable economic paradigm in the wake of the financial crisis and, as a way of strengthening the connection between social values and market outcomes.
Single crystal ferroelectrics: macroscopic and microscopic studies
Keywords: domain evolution
X-ray diffraction
barium titanate
PMN-PT
Single crystal ferroelectrics
Piezoelectrics
in-situ observations

The aim of this thesis was to improve the understanding of microstructure in single crystal ferroelectrics. This was achieved through macroscopic testing of Lead Magnesium Niobate – Lead Titanate (PMN-PT) and microscopic observations of Barium Titanate (BT) single crystals.
Multi-axial polarization rotation tests on PMN-PT showed a gradual increase in the change in dielectric displacement due to ferroelectric switching as the electric field is applied at increasing angles to the initial polarization direction. A relatively high remnant polarization for loading angle near to 90° suggested that PMN-PT is more polarizable in certain directions. Strains measured in two directions, parallel to the electric field and perpendicular to the electric field, showed a noticeable variation on two opposite faces of the specimen suggesting an effect of local domain configurations on macroscopic behaviour. A micromechanical model gave an insight into the switching systems operating in the crystal during the polarization rotation test.
Domain structure in BT was mapped using synchrotron X-ray reflection topography. By making use of the angular separation of the diffracted reflections and specimen rocking, different domain types could be unambiguously identified, along with the relative tilts between adjacent domains. Fine needle domains (width ≈ 10μm) were successfully mapped providing a composite topograph directly comparable with optical micrograph.
The domain structure was confirmed using other techniques such as piezoresponse force microscopy and atomic force microscopy/scanning electron microscopy and optical observations on the etched crystal. Results show that combined use of multiple techniques is necessary to gain a consistent interpretation of the microstructure. Finally, domain evolution in BT under compressive mechanical loading was observed in-situ using optical and X-ray diffraction techniques providing a series of images that show ferroelastic transition. The domain configurations influence the switching behaviour and constitutive models that can account for such effects need to be developed. Quantitative and qualitative data presented in this thesis can assist model development and validation.
Prevalence, perceptions and potential interventions: a mixed methods investigation of childhood overweight and obesity among a pro-poor cohort in Peru
Keywords: Risk Factors
Interventions
Childhood Overweight and Obesity
Qualitative Research
Peru
Prevalence
Perceptions

Over the past 20 years there has been a clear shift in Peru’s mortality profile towards non-communicable diseases. As part of this transition, childhood overweight and obesity (O&O;) has become a growing public health concern. In order to address this challenge, context-specific information is needed concerning prevalence, associated factors and culturally appropriate interventions. To this end, I conducted a mixed methods study using a socio-ecological framework to investigate childhood overweight and obesity in Peru.
This study found a prevalence of 19.2% overweight and 8.6% obesity among children aged seven to eight in a pro-poor cohort in Peru. Factors associated with being overweight in this cohort included: a high socioeconomic status, living in metropolitan Lima, an O&O; mother, being male and being an only child or having only one sibling. The quantitative analysis highlighted the prevalence in O&O; in this population and revealed a number of relationships explored in more depth via interviews and focus group discussions. The qualitative component of this research explored these associations amongst a sub-sample of children, parents and teachers in three distinct geographical regions in Peru. My qualitative research showed that parents, teachers and children are aware of the health implications of childhood overweight and obesity and that they have a sophisticated understanding of the many factors that influence its aetiology. Participants also had many suggestions for ways to address this issue in their community. This information was complemented by a systematic review and meta-analysis of the evidence of childhood O&O; interventions that took place in Latin America published between 1990 and 2011. A combination of diet, physical activity and pharmaceutical strategies have shown modest effect on BMI reduction in O&O; children, but more evidence is needed for effective population-level prevention strategies.
The findings highlight the need for comprehensive, multi-level interventions. Notable intervention components include: kiosco reform, junk food taxation, creation of recreational space and enhancement of school-based physical activity programmes. To accomplish this, communities need to be mobilised and work together with school administration, municipal and national government.
Stories of a failed nation; Sudanese politics 1945–69
Keywords: nationalism
elections
colonialism
imperialism
political parties
independence
Sudan

Between 1945 and 1969 the Sudanese achieved independence and overthrew a military junta with a popular uprising. Nevertheless both democratic periods were quickly ended by military coups. At the same time a civil war divided the country. The thesis asks why the democratic structures were so unstable, and unable to end the conflict between north and south. It argues that the ideas about the Sudanese nation by different groups were so contradictory, that no nation could be built. As a result, the political system failed to find a stable form and to deliver policy results to the constituents.
The thesis is using political parties as units of analysis and primarily the constitutional process and, secondarily, questions of independence and sovereignty, as prisms. It discusses the history of the political parties within the context of the political history of Sudan. The discussions about the constitution are understood as one form of expressing ideas about the nation. The thesis presents the different suggestions for the constitution by different parties, especially in regards to governance, federalism, and religion. These contradictory ideas led to the failure of the constitution writing process.
The thesis argues that the contradictory positions of the parties created a dual deadlock, which led to a breakdown of democracy. Firstly, due to reciprocal distrust, widely diverging platforms, and generally the difficulty of forming coalition governments, especially in the absence of a democratic tradition, coalitions became extremely unstable and politicians were forced to invest a lot of time and effort to keep coalitions alive and in consequence concrete political actions did not receive enough attention. Secondly, the divergent perceptions of the nation led to a situation where they stopped to see each other as part of the same nation and therefore stopped to recognise others as legitimately participating in the political process.
Tectonic motions and earthquake deformation in Greece from GPS measurements
Keywords: Egion
earthquake
GPS
seismic hazard
geophysical inversion
Greece
Grevena
Gulf of Korinthos (Corinth)

Sites in a 66-station geodetic network in central Greece have been occupied up to six times since 1989 using GPS surveying, and accurate positions have been computed using fiducially-improved or precise orbits. Site velocities are calculated under the assumption that they are constant with time, after correcting for co-seismic effects, and that the position of the fixed base station (and hence the entire network) may be subject to small errors. Low-order polynomial expressions do not fit the velocity field well. The pattern of observed strain closely resembles that derived from independent geodetic observations made over a hundred-year time-scale. Significant geodetic strain is observed across the Gulf of Korinthos, even after the co-seismic displacement field of the Ms=6.2 1995 Egion earthquake has been removed by forward modelling. Geodetic strain is higher in the western than eastern Gulf, in contrast to the seismic strain which is similar throughout. Seismic strain matches geodetic strain in the east, but a significant deficit of seismic moment exists in the west which may represent a high earthquake hazard in the medium term. The Ms=6.6 1995 Grevena earthquake struck a previously seismically quiet region well covered by a recent triangulation / trilateration survey. Ninety-one points from this network were reoccupied with GPS immediately after the earthquake, and site displacements computed. To invert for the earthquake source parameters from the geodetic displacement field, a novel inversion scheme is used which combines the Monte-Carlo and simplex approaches. A priori parameters are not required, even though the inverse problem is strongly nonlinear. The resulting focal mechanism agrees well with the global CMT solution and locally observed aftershocks, but implies a significantly higher scalar moment than do seismological studies. A network for observing post-seismic deformation has been established, which in view of the low background seismicity seems likely to provide significant results.
An amplitude analysis of the four body decay D0 → K+K−π+π− and a study on the π+π− S wave
for the decay D0 → K0S π+π−
Keywords: four-body decays
flavour physics
amplitude analysis
Dalitz
CP violation

The angle γ, with an uncertainty of approximately 10° is the least well constrained angle of the unitary triangle. Better experimental constraints on this parameter are required in order to provide a consistency check on the standard model description of CP violation. A promising strategy for measuring gamma involves exploiting interference effects present in B± → DK± decays where the D subsequently decays to a three or four body final state. The three body decay D → KS 0p+p- and the four body decay D0 → K+K-p+p- are suitable candidates for making such a measurement. However independent knowledge of the decay structure of these decays is required.
The impact of the model, used to describe the p+p- S wave, in the D0 → K+K-p+p- decay, on the uncertainty in the measurement of γ is estimated via a simulation study. It is determined that the uncertainty on a γ measurement would be compromised by this model uncertainty within one year of LHCb data running.
The four body decay D0 → K+K-p+p- also provides a candidate for making a γ measurement. This decay is expected to display a rich resonant structure. An understanding of this decay may also provide an insight into low energy QCD in addition to allowing a search for CP violation. Only one previous amplitude analysis has been performed on this decay.
Using data collected at the CLEO-II.V, CLEO-III and CLEO-c experiments an amplitude model is developed for the D0 → K+K-p+p- decay. This model is qualitatively similar to that produced in the previous analysis although the model presented in this thesis considers higher orbital angular momentum states and distinguishes between conjugate states that the previous model did not. A search for CP violation is also carried out using the D0 → K+K-p+p- decay data. A positive confirmation of CP violation at the level of sensitivity provided by this decay data would provide evidence for a level of CP violation which could not be accounted for within the standard model. No significant evidence for CP violation is observed in this decay.
A toy MC study was carried out in order to determine the sensitivity to γ which may be achieved using this decay. In this study, sets of 1000 B+ and B- events are generated and the decay model developed for the D → K+K-p+p- decay is used to describe the D decay. The sensitivity to γ determined in this study is 11°.
John Hooper and his networks
Keywords: prosopography
Worcestershire
Gloucestershire
social network analysis
networks
Reformation History

The research is a study of the context of the life and work of John Hooper, Bishop of Gloucester and Worcester, 1551-1555. It charts the nature of his relationships with friends, patrons, mentors, colleagues, and lay and clerical supporters and opponents in England and on the Continent, through the study of ecclesiastical, political, business and economic, intellectual, official and judicial, kinship and social networks in which he was involved. Its purpose is to reveal the complex mix of societal and confessional pressures influencing Hooper's approach and constraining his freedom of manoeuvre, and to a large extent determining how successful he was at achieving change. The study reveals key determinants of the nature and direction of the Reformation in England. It shows that the pressure to change doctrinal allegiances and to accommodate reformed church practices challenged not only personal confessional loyalties but also the very framework of society; that is, familial and social ties, economic, business and judicial groupings, educational affiliations, and ruling oligarchies. Within these societal networks there existed the momentum for, and resistance to, religious change. Confessional allegiances were just part of a complex mix of political and social pressures that included the exercise of patronage and protection, the use of conflict and compromise, the practise of different obligations, allegiances and loyalties, the employment of status and kinship, and the accommodation of various alliances and means of association. All of these influenced Hooper's approach and scope for action. As such, the research provides insight into why and how, in the development of the newly-reformed church in England, thoroughgoing religious change was resisted and contained.
Evaluating the impact of a sport-for-development intervention on the physical and mental health of young adolescents in Gulu, Uganda - a post-conflict setting within a low-income country
Keywords: physical fitness
sport-for-development
mental health
developing country
post-conflict
low-income country
sport
physical activity
health

Introduction: Physical inactivity is thought to contribute to the emergence of non-communicable diseases in post-conflict settings of low-income countries. Sport-for-development (SfD) organisations in these regions claim to improve the health of programme participants. However, there is a paucity of supporting evidence. I assessed the impact of a voluntary community-based SfD intervention on the physical activity (PA), physical fitness (PF) and mental health (MH) of adolescents in Gulu, Uganda.
Methods: The Acholi Psychosocial Assessment Instrument (APAI), standing broad jump (SBJ), multi-stage fitness test (MSFT) and BMI-for-age (BFA) were adapted to the local context. I tested their feasibility and reliability with a repeat-measures design (n=70). A cross-sectional analysis of a random sample was used to assess the local needs and establish the PF and MH of the adolescents reached by the intervention (n=1464). This was also the baseline assessment for the impact evaluation. It comprised a randomised control trial (n=144) nested within a cohort study (n=1400) and triangulated by cross-sectional assessment of PA using accelerometry (n=54).
Results: The adapted PF and MH measures demonstrated good intra-tester reliability (ICC>0.75). Adolescents in Gulu predominantly had “healthy” BFA (>90%). They performed better than global norms for the SBJ (p<0.001), but worse for the MSFT (p<0.05). The girls who registered for the intervention had higher PF at baseline (p<0.05) and experienced no significant benefits when compared to the community. The aerobic capacity of the boys intervention group increased relative to the community (p<0.01), but was not significantly different to the trial control group whose PF also improved. The PA results concurred with this finding. Boys in the intervention group experienced a deterioration in MH relative to their peers (p<0.05).
Implications: It is feasible to apply rigorous evaluation methods to SfD interventions. Although adolescents in Gulu have poor aerobic capacity, a voluntary programme may not reach those at risk. Interpreting the impact evaluation was limited by a lack of programme development theory, but suggested that opportunities for non-competitive play may confer PF benefit without harming MH. Further investigation is warranted.
Why Three? An exploration of the origins of the doctrine of the Trinity with reference to Platonism and Gnosticism
Keywords: Platonism
Apologists
triads
Trinity
Gnosticism

In this thesis I explore the emergence of the Christian triad with reference to two contemporary movements: Middle Platonism and Gnosticism. The earliest Christian writer to enumerate the three constituents of what would become the Christian Trinity is Justin. In addition to his three extant works, Justin’s triadology can be diagnosed from those he directly influenced – Tatian and Athenagoras – who I have (somewhat artificially) grouped under the heading the “school of Justin”. The ontological triad adopted by these Christian thinkers is compared with the triads of Middle Platonism and Gnosticism, both in terms of their structure and in terms of the function and ontological status of the individual constituents of these triads.
In this thesis I propose that a liturgical triad of primitive Christianity, the trine baptismal formula, was conflated by the “school of Justin” with the ontological triad of Middle Platonism, resulting in three referents of the baptismal formula being embued with new functions and ontological status. Whilst emerging as a hierarchical triad, the logic of Platonic ontology when combined with Christian tradition required the sharp distinction between God, as Being, and all other things resulting in a Christian triad that was also a unity. This new triad became fixed as a central tenet of Christianity.
I find no plausible connection between any known Gnostic triad and the triad of the “school of Justin”. There is some interaction between Gnostic and Platonic thought during this period. It is possible that the Triple-Powered One pre-empted the Being-Mind-Life triad of Neoplatonism.