The work presented in this thesis investigates transitions between quantum states in superconducting double dots (SDDs), a nanoscale device consisting of two aluminium superconducting islands coupled together by a Josephson junction, with each dot connected to a normal state lead. The energy landscape consists of a two level manifold of even charge parity Cooper pair states, and continuous bands corresponding to charge states with single quasiparticles in one or both islands. These devices are fabricated using shadow mask evaporation, and are measured at sub Kelvin temperatures using a dilution refrigerator. We use radio frequency reflectometry to measure quantum capacitance, which is dependent on the quantum state of the device. We measure the quantum capacitance as a function of gate voltage, and observe capacitance maxima corresponding to the Josephson coupling between even parity states. We also perform charge sensing and detect odd parity states. These measurements support the theoretical model of the energy landscape of the SDD. By measuring the quantum capacitance in the time domain, we observe random switching of capacitance between two levels. We determine this to be the stochastic breaking and recombination of single Cooper pairs. By carrying out spectroscopy of the bath responsible for the pair breaking we attribute it to black-body radiation in the cryogenic environment. We also drive the breaking process with a continuous microwave signal, and find that the rate is linearly proportional to incident power. This suggests that a single photon process is responsible, and demonstrates the potential of the SDD as a single photon microwave detector. We investigate this mechanism further, and design an experiment in which the breaking rate is enhanced when the SDD is in the antisymmetric state rather than the symmetric state. We also measure the quantum capacitance of a charge isolated double dot. We observe 2e periodicity, indicating the tunnelling of Cooper pairs and the lack of occupation of quasiparticle states. This work is relevant to the range of experiments investigating the effect of non-equilibrium quasiparticles on the operation of superconducting qubits and other superconducting devices.

FAPEMIG - Fundação de Amparo a Pesquisa do Estado de Minas Gerais / O conhecimento teórico e experimental acumulado nas últimas décadas sobre pontos quânticos semicondutores (PQs) impulsiona o surgimento de um grande número de propostas atuais de utilizá-los em sistemas híbridos. A habilidade de controlar suas propriedades optoeletrônicas, bem como o domínio de sofisticadas técnicas de fabricação, tornaram-os candidatos ideais para formar junções com supercondutores (SCs), cujas características individuais são também notáveis. Essas junções podem ser simples, com um único PQ acoplado a um SC, ou múltiplas: a conexão de dois terminais SCs através de um PQ (junção tipo Josephson) e a junção de dois PQs através de um SC. Esta última forma um separador de pares de Cooper, dispositivo sugerido como fonte de partículas emaranhadas, que depende fundamentalmente da ocorrência de reflexão de Andreev cruzada (CAR) nas interfaces da junção. Junções de PQs com SCs e com supercondutores topológicos também tem sido propostas em sistemas de dois níveis formando qubits para a computação quântica trivial e topológica. Embora o estudo das junções PQ-SC esteja em evidência atualmente, a revisão da literatura mostra que a análise do regime transiente foi pouco explorada. Por isso, abordamos neste trabalho o transporte de cargas em uma junção PQ-SC-PQ com resolução temporal. Utilizando técnicas de função de Green de não-equilíbrio, particularmente, o formalismo de Kadanoff-Baym, escrevemos um conjunto de equações diferenciais acopladas, solucionado numericamente. Analisando as oscilações de Rabi que surgem na evolução temporal da corrente elétrica e das ocupações dos PQs, fomos capazes de identificar assinaturas de mecanismos de espalhamento através da junção, isto é, o tunelamento direto e a CAR. Adicionalmente, propusemos a expansão deste sistema pela sua inserção na estrutura de um fotodiodo, aplicando luz laser sobre um dos PQs. Os resultados mostram que ocorre a separação dos níveis opticamente excitados em dubletos de Autler-Townes, para acoplamentos fracos entre os PQs. Consequentemente, é observada a ocorrência de CAR, mediada pelo laser aplicado, através dos níveis que compõe o dubleto. Os resultados tem dependência também com a tensão fonte-dreno aplicada ao dispositivo, que pode estar no limite de bias alta (HB) ou zero (ZB). Este é o primeiro trabalho a analisar a separação de pares de Cooper assistida por fótons em uma junção PQ-SC-PQ, em regime de não-equilíbrio. Embora os resultados experimentais ainda sejam escassos, a inclusão de um SC em um fotodiodo de PQs híbrido permite novos mecanismos de formação de fotocorrente, abrindo novas possibilidades de aplicações desse sistema. / The theoretical and experimental knowledge accumulated in the last decades on semiconductors quantum dots (QDs) impulses the emergence of many current proposals for using them in hybrid systems. The ability to control their optoelectronic properties, as well as the control of fabrication techniques, made them the perfect candidates to compose junctions with superconductors (SCs), whose individual characteristics are also remarkable. These junctions can be simple, with a single QD coupled to a SC, or multiple: a connection of two superconducting terminals through a QD (a Josephson-like junction) and the junction of two QDs through a SC. The latter is known as a Cooper-pairs splitter, a device suggested as a source of entangled particles, for which is required the occurrence of crossed Andreev reflection (CAR) on the interfaces of the junction. Junctions of QDs with SCs and with topological SCs have also been proposed in two-level systems as qubits for both trivial and topological quantum computation. Despite the study of QD-SC junctions being currently in evidence, the literature review shows that the analysis of transient regime was little explored. Therefore, we address in this work the topic of time-dependent charge transport in a QD-SC-QD junction. By using non-equilibrium Green functions techniques, particularly, the Kadanoff-Baym formalism, we write down a set of coupled differential equations, which is numerically solved. Examining the Rabi oscillations that appears on the time evolution of electric current and QDs occupations, we were able to identify signatures of the scattering mechanisms through out the junction, i. e., direct tunnelling and CAR. Additionally, we propose to use this system as a photodiode, with the aid of a laser beam over one of the QDs. The results show the splitting of the optically excited states in Autler- Townes doublets, for a weak coupling between the QDs. Hence, CAR mediated by the applied laser was observed through the energy levels that compose the doublet. The results depend also with the source-drain potential applied to the device, which can be high bias (HB) or zero bias (ZB). The present work is the first to analyse the splitting of Cooper pairs assisted by photons in a QD-SC-QD junction, in nonequilibrium regime. Although the experimental results are still sparse, the inclusion of a SC in a QD hybrid photodiode allows new mechanisms of photocurrent formation, creating possibilities in future applications. / Tese (Doutorado)

This study examines a small body of 19th-century American literature about the Antarctic: Adam Seaborn's (pseud.) Symzonia (1820), Edgar Allan Poe's "MS. Found in a Bottle" (1833) and The Narrative of Arthur Gordon Pym (1838), Peter Prospero's (pseud.) "The Atlantis" (1838-39), and James Fenimore Cooper's The Monikins (1835) and The Sea Lions (1849). These were written in a transitional phase in the history of the Antarctic. At the start of the period, the region was almost completely unknown. Towards the end of the period, however, the region had been mapped in its essence, and the existence of an Antarctic continent had been verified. For complex reasons, the region came into cultural focus in the U.S. during the 1820s to 40s, culminating in the first major American scientific expedition in 1838-42 to explore the South Seas and the Antarctic. The study is primarily historical, tracing ideas to their historical contexts in order to determine what these authors used the unknown space of the Antarctic for. These texts were written in imaginative response to contemporary notions of the Antarctic, which is reflected in the mode of representation. The literature is in the mode of speculative fiction-most of texts imagining a tropical, inhabited Antarctic-up until the region is explored, at which point it turns to realism. The texts fall into three categories: the utopian, liminal, and realistic. The utopian texts-Symzonia, The Monikins, and "The Atlantis"-are works of social criticism, using the blank space of the Antarctic to treat a diverse range of issues, including politics, evolutionary theories, race, and gender. Poe's "MS" and Pym represent the liminal category; they dramatize the anticipation of an imminent Antarctic discovery, narrating up to a point of revelation, only to stop short. The Sea Lions is the only realistic text, coming after the Antarctic is explored. Here the knowledge of the Antarctic has solidified into the environment we know today, but with religiously symbolical overtones.

Throughout arid and semi-arid inland Australia, many extensive floodplains occur in association with rivers which are amongst the most hydrologically variable in the world. As rainfall in these areas is characteristically low and patchy, conditions in Australia's 'dryland' floodplains fluctuate unpredictably between extended periods of drought and huge floods that transform vast areas into wetlands, often for months at a time. Vegetation in these floodplains is commonly dominated by short grass and forb associations and patches of open succulent shrubland which are attributed with high ecological and socio-economic values due to their provision of habitat to a diverse array of terrestrial and aquatic fauna and their productive native pasture growth. In temperate and tropical floodplains, a substantial number of studies have shown that plant community composition and structure is determined primarily by flow and alterations to flow in these areas, through water extraction or river regulation, have resulted in many changes to the vegetation including loss of biodiversity and mass invasions of exotic species. Despite increasing pressure for water resource development in 'dryland' regions, relatively little is known regarding the effects of highly variable flows on the vegetation dynamics of arid floodplains, particularly in Australia. This thesis addresses this knowledge gap by examining the role of flow in the vegetation dynamics of a large arid floodplain in central Australia: the Cooper Creek floodplain. The effects of flow on plant community dynamics, from an organism level to that of the landscape, are examined across a range of spatial and temporal scales. Results are presented from a two year temporal vegetation survey during which time two flood pulse events of differing sizes occurred. A large-scale spatial survey was also conducted to determine the effects of flood history on spatial variation in plant community composition and structure. The composition of the soil seed bank and its contribution to vegetation dynamics were additionally investigated through a series of germination trials. Amongst common arid floodplain plants, life history traits that enable persistence under variable hydrological conditions were also considered via several experiments aimed at determining the effects of flow on the outcomes of various life history stages including germination, growth and dispersal. Throughout the study, results are presented for plant groups that were predefined on the basis of life form, life span and taxonomic divisions within these categories. Plant community composition and structure in the Cooper Creek floodplain exhibits significant shifts both temporally, in response to flood pulse wetting and drying, and spatially, in response to flood history. Flood pulse inundation has the potential to influence each life history stage across the range of plant groups present and the outcomes of these appear to be determined by hydrological attributes such as flood pulse timing, duration and rate of drawdown. Vegetation consequently exhibits gradual zonation on a gradient of flood frequency along which plant groups occur at predictable locations depending on their life history traits and recent hydrological conditions. A substantial proportion of species display ruderal life history traits including large, persistent soil seed banks and rapid life cycles which enable escape in time from the stresses associated with flooding and drought. These species, mostly comprising annual monocots and forbs, are widespread throughout the landscape and their presence in the extant vegetation is related primarily to the time since the last flood pulse event and the hydrological attributes of this. Perennial species, particularly shrubs, do not appear to rely similarly on the soil seed bank for recruitment and their distribution in the floodplain vegetation is likely to be determined more by their ability to tolerate either flooding or drought. Overall, this study demonstrates that flow, despite its variability, has an overriding influence on vegetation dynamics in the arid floodplain of the Cooper Creek. The spatial and temporal variability of flow maintains a heterogeneous mosaic of plant communities of differing composition and structure. Given this close relationship between flow and vegetation dynamics, anthropogenic alterations to flow are likely to result in changes to the vegetation including homogenisation of plant communities across the floodplain landscape and eventual loss of biodiversity.

The aim of the present thesis is to study radical criticism of psychiatry in public discussion in Sweden between 1968 and 1973. Although it was not the first time psychiatry had been challenged, the debate during these years displayed an unprecedented intensity. What is mental illness – a myth, an etiquette, an illusion? Is psychiatry a means of social control? Such were the questions raised at the time. In my thesis, I study the contexts as well as the arguments of these discussions. To this end, a great variety of sources have been consulted: books, newspapers, magazines, films etc. In part, the Swedish debate on psychiatry ran parallel to international discussions on the topic, which have been regarded as a manifestation of anti-psychiatry. This standpoint is often associated with psychiatrists such as R. D. Laing, David Cooper and Thomas Szasz. In my thesis, I challenge the concept of anti-psychiatry, arguing that other concepts are better suited to capture the diversity of the debate in all its nuances. Thus, I make use of radical and reformatory criticism – concepts which have been suggested by the sociologist Tommy Svensson – while also seeking to develop them further. In addition to the international perspective, the psychiatry debate must also be interpreted in its specifically Swedish context. One aspect of this is the Swedish tradition of Government Official Reports: psychiatry had been subject to many investigations prior to the debate in the 1960s and 1970s, and others would follow in its wake. Another characteristic feature of the Swedish debate is two events that formed very suitable targets for critique: Sociopatutredningen and Mentalhälsokampanjen. These events seemed to confirm the most farreaching concerns of the radical critics, namely that psychiatry is a means of social control.

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Thesis (Ph. D.)--University of Oregon, 2005. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 186-199). Also available for download via the World Wide Web; free to University of Oregon users.

This thesis is focused on the representation and characterization of female characters in the novel The Deerslayer from The Leatherstocking Tales pentalogy from James Fenimore Cooper in contrast to the concept of female characters in the book from Louisa May Alcott Little Women. There is analyzed images of female fictional heroines living in the American wilderness in the years 1740-1805, and these findings are compared with the representation of women in the 19th century domestic novel Little Women. The way of creating female characters is analyzed in relation to the other characters, the space in which they live, the storyline and contemporary values. This analysis should in a literary historical aspect reveal how much the role of a woman becomes a mere fulfillment of a simplified scheme and how it also has many meanings of full-fledged components in literary work. The author of this thesis also focuses on the influence of the environment on the formation of female characters and tracks their role not only in American novels but also in the society. Key words woman, gender, novel, cult of True Womenhood, James Fenimore Cooper, Louise May Alcott, topoi of the forest, home, american wildernes

The gay male emerged as a visible public consumer during 1990s, when the LGBTQ movement in the United Kingdom and the United States was marked by conflicting commercial and political motives, heightened by the AIDS crisis. The cultural tension surrounding the gay male subject was reflected through various literary expressions. In the United Kingdom Mark Ravenhill’s Shopping and Fucking (1996), as part of the in-yer-face theatre, exploded in the face of the bourgeoisie. In the US America Dennis Cooper’s highly publicised George Miles Cycle (1989-2000), was followed by The Sluts (2004) as part of the transgressive literature, provoking both straight and gay communities. Through an analysis of themes such as capitalism, commerce, hyperreality, internalised fear, desire, and violence in the works, an alternative image of the gay male is distinguished. This is an image of the gay male subject that is complex, multi-faceted, contradictory and polyvalent. The characters relate differently to the hegemonic hyperreal role model, but are exposed to the same social structure that dictates their living conditions and positioning them as objects possible to practice violence on. The works provide a widened and complicated image the public image of the gay male. Their countercultural narratives trace how the gay male subject have been affected by the heteronormative society. When the provided stereotype is too narrow to express the burden and the joy of the contemporary gay male subject, alternatives, like the depictions by Ravenhill and Cooper, may allow the subject to fully possess the gay experiences of pain, sorrow and anger that he has been forced to bear. This research explores how the violence within the texts holds a liberating potential.