VictorJuiz/thesis huggingface dataset:
Quantum information theory and the foundations of quantum mechanics
Keywords: quantum information theory
quantum mechanics
quantum computation

This thesis is a contribution to the debate on the implications of quantum information theory for the foundational problems of quantum mechanics. In Part I an attempt is made to shed some light on the nature of information and quantum information theory. It is emphasized that the everyday notion of information is to be firmly distinguished from the technical notions arising in information theory; however it is maintained that in both settings ‘information’ functions as an abstract noun, hence does not refer to a particular or substance. The popular claim ‘Information is Physical’ is assessed and it is argued that this proposition faces a destructive dilemma. Accordingly, the slogan may not be understood as an ontological claim, but at best, as a methodological one. A novel argument is provided against Dretske’s (1981) attempt to base a semantic notion of information on ideas from information theory. The function of various measures of information content for quantum systems is explored and the applicability of the Shannon information in the quantum context maintained against the challenge of Brukner and Zeilinger (2001). The phenomenon of quantum teleportation is then explored as a case study serving to emphasize the value of recognising the logical status of ‘information’ as an abstract noun: it is argued that the conceptual puzzles often associated with this phenomenon result from the familiar error of hypostatizing an abstract noun. The approach of Deutsch and Hayden (2000) to the questions of locality and information flow in entangled quantum systems is assessed. It is suggested that the approach suffers from an equivocation between a conservative and an ontological reading; and the differing implications of each is examined. Some results are presented on the characterization of entanglement in the Deutsch-Hayden formalism. Part I closes with a discussion of some philosophical aspects of quantum computation. In particular, it is argued against Deutsch that the Church-Turing hypothesis is not underwritten by a physical principle, the Turing Principle. Some general morals are drawn concerning the nature of quantum information theory. In Part II, attention turns to the question of the implications of quantum information theory for our understanding of the meaning of the quantum formalism. Following some preliminary remarks, two particular information-theoretic approaches to the foundations of quantum mechanics are assessed in detail. It is argued that Zeilinger’s (1999) Foundational Principle is unsuccessful as a foundational principle for quantum mechanics. The information-theoretic characterization theorem of Clifton, Bub and Halvorson (2003) is assessed more favourably, but the generality of the approach is questioned and it is argued that the implications of the theorem for the traditional foundational problems in quantum mechanics remains obscure.
Analogy between equilibrium of structures and compatibility of mechanisms
Keywords: deployable structures

Planar bar-and-joint mechanisms with one degree-of-freedom are widely used in deployable structures and machines. Such mechanisms are designed to undergo a specific motion, which can be described mathematically by plotting out the compatibility conditions, resulting in a curve called compatibility path. It has been observed that compatibility paths can develop singularities similar to that of equilibrium paths of elastic structures. This dissertation studies singularities occurring in compatibility paths with the aid of knowledge in the theory of structural stability. An analogy is set up between the equilibrium path of elastic structures and the compatibility path of mechanisms with a single degree-of-freedom incorporating the different types of bifurcation, effects of imperfections and detection of singularities. It is shown that the fundamentally distinct critical points such as limit points and bifurcation points can also appear in compatibility path. Methods used to singularities for compatibility conditions of mechanisms and equilibrium of structures are unified so that they can be used for both cases. A formulation of potential energy for mechanisms is also proposed in analogy with the potential energy function used in structural analysis. Further analysis of the mechanisms is carried out to demonstrate that singularities of compatibility paths can also be dealt with by the elementary catastrophe theory similar to the stability theory. A relationship is established between the mathematical formulation of different compatibility bifurcations and the canonical forms of catastrophe types. Examples of mechanisms demonstrating the existence of cuspoids of the compatibility conditions are given. An overall classification of the compatibility paths is also proposed.
The syntax and semantics of tense-aspect stem participles in early Ṛgvedic Sanskrit
Keywords: participles
Sanskrit
lexical-functional grammar
syntax
semantics

In this thesis I investigate the syntax and semantics of tense-aspect stem participles in the Ṛgveda, focusing primarily on the data from the earlier books II–VII and IX, seeking to establish a comprehensive and coherent analysis of this category within the linguistic system of Ṛgvedic Sanskrit. In recent literature tense-aspect stem participles are usually treated as semantically equivalent to finite verbs wherever possible, but contradictorily where they differ from finite verbs their adjectival nature is emphasized. I argue that tense-aspect stem participles are a fundamentally verbal formation and can be treated as inflectional verb forms: they are adjectival verbs rather than verbal adjectives. At the same time, however, they constitute an independent sub-category of verb form which is not necessarily semantically dependent on corresponding finite stems.
I examine the syntactic and semantic properties of tense-aspect stem participles both in relation to finite verbal forms and their wider syntactic context, formalizing the evidence in the framework of Lexical-Functional Grammar. Consequently I am able to categorize the syntactic and semantic deviations which many participles exhibit in comparison to finite verbal forms. I contend that many such forms cannot be treated synchronically (and sometimes diachronically) as participles, but form distinct synchronic categories. My analysis permits a considerably more refined definition of the category of tense-aspect stem participles, dependent on clear morphological, syntactic and semantic criteria, as opposed to the usual, purely morphological, definition.
From a diachronic perspective I argue that the category of tense-aspect stem participles as found in the Ṛgveda more closely reflects an inherited Proto-Indo-European category of tense-aspect stem participles than is usually assumed. I also reconsider theoretical treatments of participial syntax and semantics, and develop a more precise typology of non-finite verb systems which adequately accounts for Sanskrit participles.
Milton and material culture
Keywords: early modern literature
biblical narratives
early modern England
Milton
material culture

In contradistinction to critical trends which have rendered Milton’s thought disembodied, this thesis studies how seventeenth-century material culture informed Milton’s poetry and prose at the epistemic level and by suggesting a palette of forms for literary play.
The first chapter explores the early modern culture of fruit. At the epistemic level, practices of fruit cultivation and consumption inform Milton’s imagination and his vocabulary, thereby connecting their historic-material lives with their symbolic ones. Milton further turns commonplace gestures of fruit consumption into narrative devices that frame discussions of agency, aspiration, sinful and right practice.
The second chapter examines two floral catalogues to discover how they find shape through the epistemologies of flowers, ceremony, and decorative arts. Here material culture shapes literary convention, as one catalogue is found to secret ceremonial consolation in its natural ingenuousness, while the other’s delight in human physicality upsets the distinctions between inner virtue and outer ornament, faith and rite.
In the third chapter, urban epistemologies of light, darkness, movement, and space are examined through urban phenomena: skyline, suburbs, highways, theft, and waterways. By interpellating contemporary debates, these categories anatomise fallen character, intent, action, and their consequences. Milton’s instinctive distaste for urban nuisances is interesting in this Republican figure and is subversive of some ideologies of the text.
Discursive and material aspects meet again in the fourth chapter in a discussion of his graphic presentations of geography on the page. Usually prone to analyses of textual knowledge, they are also informed by the embodiment of knowledge as material object. Milton’s search for a fitting cartographic aesthetic for the Biblical narrative and for the rhetoric of his characters leads him to an increasing consciousness of the ideologies energising these material forms.
The fifth chapter explores Milton’s engagement with forms of armour and weapons. Military preferences for speed and mobility over armour help Milton explore the difference between unfallen and fallen being. Milton also uses his inescapably proleptic knowledge of arms and armour as a field of imaginative play for representations that are both anachronistic and typological. These lead to a discussion of imitation in the mythic imagination.
In each of these studies, we witness Milton’s consciousness of his temporal and proleptic location, and his attempts to marry the temporal and the pan- or atemporal. In the conclusion I suggest that Milton’s simultaneous courting of the atemporal while he is drawn to or draws on temporal material culture imply an incarnational aesthetic.
A dislocation model of plasticity with particular application to fatigue crack closure
Keywords: plasticity models
fatigue
stress intensity
area plasticity model
dislocation theory
McKellar beta parameter
Prandtl-Reuss flow rule
crack growth
complementary shear planes
slip planes
plasticity induced fatigue crack closure

The ability to predict fatigue crack growth rates is essential in safety critical systems. The discovery of fatigue crack closure in 1970 caused a flourish of research in attempts to simulate this behaviour, which crucially affects crack growth rates. Historically, crack tip plasticity models have been based on one-dimensional rays of plasticity emanating from the crack tip, either co-linear with the crack (for the case of plane stress), or at a chosen angle in the plane of analysis (for plane strain). In this thesis, one such model for plane stress, developed to predict fatigue crack closure, has been refined. It is applied to a study of the relationship between the apparent stress intensity range (easily calculated using linear elastic fracture mechanics), and the true stress intensity range, which includes the effects of plasticity induced fatigue crack closure. Results are presented for all load cases for a finite crack in an infinite plane, and a method is demonstrated which allows the calculation of the true stress intensity range for a growing crack, based only on the apparent stress intensity range for a static crack.
Although the yield criterion is satisfied along the plastic ray, these one-dimensional plasticity models violate the yield criterion in the area immediately surrounding the plasticity ray. An area plasticity model is therefore required in order to model the plasticity more accurately. This thesis develops such a model by distributing dislocations over an area. Use of the model reveals that current methods for incremental plasticity algorithms using distributed dislocations produce an over-constrained system, due to misleading assumptions concerning the normality condition. A method is presented which allows the system an extra degree of freedom; this requires the introduction of a parameter, derived using the Prandtl-Reuss flow rule, which relates the magnitude of slip on complementary shear planes. The method is applied to two problems, confirming its validity.
Cultural politics of user-generated encyclopaedias: comparing Chinese Wikipedia and Baidu Baike
Keywords: online encyclopaedias; social media; user-generated content; China

The question of how the Internet affects existing geo-cultural or geo-linguistic communities in relation to nation-states has continued to receive attention among academics and policymakers alike. Language-based technologies and services that aggregate, index, and distribute materials online may reshape pre-existing boundaries of the relationship between users and content, for instance with different language versions of user-generated encyclopaedias or different local versions of search engines. By comparing two major Chinese online encyclopaedias, Baidu Baike and Chinese Wikipedia, this thesis investigates whether the Internet overcomes, shifts, or reinforces boundaries among Chinese language users. The Chinese language provides an excellent case for examining the boundary question. While the Internet can potentially connect the largest number of native speakers around the world, the majority (i.e. those from mainland China) face an Internet censorship and filtering regime that may limit this very potential. Modern Chinese history has also complicated the cultural-political boundaries among the regions of mainland China, Hong Kong, and Taiwan.
This thesis compares the conditions and outcomes of their respective editorial processes, content features, and users’ reception. Multiple findings emerge from a combination of quantitative and qualitative methods, including content analysis, webometrics, and search engine result visibility tests. These methods show that boundaries are drawn in the process of creating, linking, and searching content on the Chinese Internet. Their geolinguistic extent differs, a phenomenon that reflects the cultural-political division between mainland China and the rest of Chinese-speaking world. Both the findings and methods of the thesis have important implications for research and policy for understanding the globalizing regionalization and nationalization effects of the Internet.
The response of submerged structures to underwater blast
Keywords: sandwich plate
fluid-structure interaction
shock waves
dynamic loading
underwater blast
blast mitigation
finite elements
blast loading
shock tube
cavitation

The response of submerged structures subject to loading by underwater blast waves is governed by complex interactions between the moving or deforming structure and the surrounding fluid and these phenomena need to be thoroughly understood in order to design structural components against underwater blast.
This thesis has addressed the response of simple structural systems to blast loading in shallow or deep water environment. Analytical models have been developed to examine the one-dimensional response of both water-backed and air-backed submerged rigid plates, supported by linear springs and loaded by underwater shock waves. Cavitation phenomena as well as the effect of initial static fluid pressure are explicitly included in the models and their predictions were found in excellent agreement with detailed FE simulations.
Then, a novel experimental apparatus has been developed, to reproduce controlled blast loading in initially pressurised liquids. It consists of a transparent water shock tube and allows observing the structural response as well as the propagation of cavitation fronts initiated by fluid-structure interaction in a blast event. This experimental technique was then employed to explore the one-dimensional response of monolithic plates, sandwich panels and double-walled structures subject to loading by underwater shock waves. The performed experiments provide great visual insight into the cavitation process and the experimental measurements were found to be in good agreement with analytical predictions and dynamic FE results.
Finally, underwater blast loading of circular elastic plates has been investigated by theoretically modelling the main phenomena of dynamic plate deformation and fluid-structure interaction. In addition, underwater shock experiments have been performed on circular composite plates and the obtained measurements were found in good correlation with the corresponding analytical predictions. The validated analytical models were then used to determine the optimal designs of circular elastic plates which maximise the resistance to underwater blast.
Haematopoietic stem/progenitor cell interactions with the bone marrow vascular niche
Keywords: Leukaemia
umbilical cord blood transplantation
CXCL12 umbilical cord blood
migration
junctional adhesion molecule-A
haematopoietic stem/ progenitor cells
Chemokine (C-X-C motif) receptor 4
CXCR4
adhesion
bone marrow vascular niche
JAM-A
Chemokine (C-X-C motif) ligand 12

Umbilical cord blood (UCB) is used as a source of haematopoietic stem cells (HSCs) for transplantation but shows defective homing to the bone marrow niche and delayed haematological reconstitution. Following transplantation, HSCs will home to the bone marrow in response to the CXCL12 chemokine, adhere to the bone marrow sinusoidal endothelial cells and then migrate into and lodge in bone marrow niches. In addition to CXCR4, a variety of molecules have been described as being important in these processes. In this laboratory, junctional adhesion molecule-A (JAM-A) was shown to be expressed on human UCB CD133⁺/CD34⁺ cells and regulated by hypoxia. In this thesis, further phenotypic studies show that this molecule is most highly expressed on human CD41a⁺ megakaryocytes and CD14⁺ monocytes/macrophages in UCB. JAM-A was also found to be expressed on all human UCB CD133⁺ cells, which have been shown by others to encompass the HSCs and early myeloid-lymphoid precursors and on the majority of CD34⁺ haematopoietic progenitor cells (HPCs). While it is also present on bone marrow sinusoidal endothelium (BMEC), JAM-A is not detected on cultured bone marrow mesenchymal stromal cells (MSCs). JAM-A blockade, silencing and overexpression experiments showed that JAM-A contributes to, but is not solely responsible for, the adhesion of CD34⁺ haematopoietic progenitor cells to IL-1β activated BMEC-60 cells and fibronectin. Lack of significance in cell migration suggested that JAM-A is more likely to act as an adhesion molecule or a regulator of adhesion rather than as a migratory molecule in such cells. Further functional studies using the proximity ligation assay highlight a potential association of JAM-A with CXCR4 and the adhesion molecules, tetraspanin CD82 and integrin β1. Mechanistic studies were commenced to establish if JAMA could modulate CXCR4 signalling following CXCL12 stimulation, but time constraints prevented these from being completed. These preliminary experiments which were carried out first in the Jurkat cell line lacking JAM-A or transduced to express JAM-A, however, suggest that JAM-A may modulate CXCL12-induced Rap1 phosphorylation and ERK1/2 phosphorylation. The former pathway is important for integrin function and the latter pathway is important in cell adhesion. The results described here, although requiring finalisation, support the hypothesis that JAM-A acts as an adhesion molecule and also may fine tune CXCR4 and integrin mediated functions on human CD34⁺ cells, thereby potentially regulating engraftment of these cells to the bone marrow niche.
Identity driven institutional work: examining the emergence and effect of a pro bono organization within the English legal profession
Keywords: institutional work
professionals
emotion work
identity work

Although a growing number of scholars suggest that the construction of identity is an important form of institutional work, the complex interactions between identities and institutions remain under-explored. In particular, few studies consider how the affective aspects of identities may inform institutional work. This thesis examines the experiences of lawyers who volunteered to create and support a legal charity. As these volunteers grew to more than twenty thousand over fifteen years, the charity gradually centralized charitable work across law firms for the first time. In this way, it transformed the institution of pro bono work within the English legal profession. Drawing on this case study, this thesis employs a grounded theory methodology to generate a conceptual framework that connects emotion work, identity work and institutional work. This framework suggests that some professionals work to re-assert and ‘remember’ aspects of their traditional identities that compete with some contemporary demands. This can prompt identity contradictions that inspire reflection on professional practices. This identity work may also encourage professionals to evoke emotions of guilt that can imbue contradictions with enough significance to create a purpose for remedial institutional work. When enabled by meso-level processes, such micro-level work can reinvigorate traditional practices and accomplish institutional change.
Generation of heralded single photons in pure quantum states
Keywords: parametric downconversion
interference
photon
single photon source
Quantum physics
pure state
spectral engineering

Single photons - discrete wavepackets of light - are one of the most fundamental entities in physics. In recent years, the ability to consistently create and manipulate both single photons and pairs of photons has facilitated everything from tests of quantum theory to the implementation of quantum-enhanced precision measurements. These activities all fall within the scope of the rapidly-growing field of quantum information - the exploitation of the properties of quantum states (and specifically their capability to exist in superpositions) to accomplish tasks that would not be possible with classical objects. One stated goal of research in quantum information is to build a device consisting of a network of quantum logic gates that can evaluate quantum algorithms. The photonic implementation of individual logic gates has already been demonstrated. However, partly due to standard methods of preparing single photons, current schemes have severe limitations in terms of scaling up from a single logic gate to multiple concatenated operations. Until now it has not been proven that single photons can be generated in pure and indistinguishable quantum states, something upon which the successful operation of optical quantum logic gates relies. This thesis presents an experimental demonstration of simultaneous generation of almost identical single photons in highly pure states from two independent sources based on parametric downconversion. This is a process of photon pair generation during the passage of a light beam through a nonlinear crystal; one photon from the resulting pair is detected to herald the other. The work herein describes, refines, and implements a technique that minimises the strong quantum correlations usually present within each pair by spectral engineering of the source. This allows the heralded single photons to be in pure states, a property that is confirmed by observing a high-visibility two-photon interference effect without spectral filtering.