1,915 research outputs found

    Robust Transport Signatures of Topological Superconductivity in Topological Insulator Nanowires

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    Finding a clear signature of topological superconductivity in transport experiments remains an outstanding challenge. In this work, we propose exploiting the unique properties of three-dimensional topological insulator nanowires to generate a normal-superconductor junction in the single-mode regime where an exactly quantized 2e2/h2e^2/h zero-bias conductance can be observed over a wide range of realistic system parameters. This is achieved by inducing superconductivity in half of the wire, which can be tuned at will from trivial to topological with a parallel magnetic field, while a perpendicular field is used to gap out the normal part, except for two spatially separated chiral channels. The combination of chiral mode transport and perfect Andreev reflection makes the measurement robust to moderate disorder, and the quantization of conductance survives to much higher temperatures than in tunnel junction experiments. Our proposal may be understood as a variant of a Majorana interferometer which is easily realizable in experiments.Comment: 5 pages, 3 figure

    Perfect transmission and Aharanov-Bohm oscillations in topological insulator nanowires with nonuniform cross section

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    Topological insulator nanowires with uniform cross section, combined with a magnetic flux, can host both a perfectly transmitted mode and Majorana zero modes. Here we consider nanowires with rippled surfaces---specifically, wires with a circular cross section with a radius varying along its axis---and calculate their transport properties. At zero doping, chiral symmetry places the clean wires (no impurities) in the AIII symmetry class, which results in a Z\mathbb{Z} topological classification. A magnetic flux threading the wire tunes between the topologically distinct insulating phases, with perfect transmission obtained at the phase transition. We derive an analytical expression for the exact flux value at the transition. Both doping and disorder breaks the chiral symmetry and the perfect transmission. At finite doping, the interplay of surface ripples and disorder with the magnetic flux modifies quantum interference such that the amplitude of Aharonov-Bohm oscillations reduces with increasing flux, in contrast to wires with uniform surfaces where it is flux-independent.Comment: 12 pages, 6 figures. v2. 2 new figures and a new appendi

    Can Forest Management Strategies Sustain The Development Needs Of The Little Red River Cree First Nation?

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    In this study, we explore whether projected socio-economic needs of the Little Red River Cree Nation (LRRCN) can be met using the natural resources to which they have access. To answer this question, we employ a dynamic optimization model to assess the capacity of the available forest base to provide for anticipated future needs of the LRRCN. Results for alternative management strategies indicate that decision-makers face significant tradeoffs in deciding an appropriate management strategy for the forestlands they control.boreal forest, First Nations, forest management, sustainability

    Minority Stress Theory: Application, Critique, and Continued Relevance

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    The minority stress model has been influential in guiding research on sexual and gender minority health and well-being in psychology and related social and health sciences. Minority stress has theoretical roots in psychology, sociology, public health, and social welfare. Meyer provided the first integrative articulation of minority stress in 2003 as an explanatory theory aimed at understanding the social, psychological, and structural factors accounting for mental health inequalities facing sexual minority populations. This article reviews developments in minority stress theory over the past two decades, focusing on critiques, applications, and reflections on its continued relevance in the context of rapidly changing social and policy contexts

    The Qualitative Interview in Psychology and the Study of Social Change: Sexual Identity Development, Minority Stress, and Health in the Generations Study.

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    Interviewing is considered a key form of qualitative inquiry in psychology that yields rich data on lived experience and meaning making of life events. Interviews that contain multiple components informed by specific epistemologies have the potential to provide particularly nuanced perspectives on psychological experience. We offer a methodological model for a multi-component interview that draws upon both pragmatic and constructivist epistemologies to examine generational differences in the experience of identity development, stress, and health among contemporary sexual minorities in the United States. Grounded in theories of life course, narrative, and intersectionality, we designed and implemented a multi-component protocol that was administered among a diverse sample of three generations of sexual minority individuals. For each component, we describe the purpose and utility, underlying epistemology, foundational psychological approach, and procedure, and we provide illustrative data from interviewees. We discuss procedures undertaken to ensure methodological integrity in process of data collection, illustrating the implementation of recent guidelines for qualitative inquiry in psychology. We highlight the utility of this qualitative multi-component interview to examine the way in which sexual minorities of distinct generations have made meaning of significant social change over the past half-century

    Social change and relationship quality among sexual minority individuals: Does minority stress still matter?

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    Objective: This study examined whether positive changes in social attitudes and policies surrounding sexual minority relationships have translated to diminished deleterious effects of minority stress on relationship quality. Background: Sexual minority emerging adults now come of age at a time of greater equality and acceptance than previous generations. Research has demonstrated consistent negative effects of stigma—theorized as minority stress—on relationship quality for sexual minority individuals. However, given the improving social climate, questions remain regarding whether minority stress has the same deleterious effects on the romantic relationships of sexual minority emerging adults. Method: Five-hundred forty-nine individuals in relationships drawn from a US national probability sample completed a survey containing validated measures of minority stressors and relationship satisfaction. Responses from emerging adults (aged 18–25) were compared to two cohorts who came of age during the HIV/AIDS crisis (aged 34–41) and post Stonewall (aged 52–59). Results: Emerging adults were more satisfied with their relationships than older cohorts. Experiences of everyday discrimination were associated with decreased relationship satisfaction for all cohorts; however, felt stigma, stigma concealment, and internalized stigma were associated with lower relationship satisfaction for older but not younger cohorts. Conclusion: Findings illustrate the continued but shifting role of minority stress and provide the first evidence that social and policy changes may have translated into more positive relationship experiences for sexual minority emerging adults
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