1,143 research outputs found

    Nonlocality and information flow: The approach of Deutsch and Hayden

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    Deutsch and Hayden claim to have provided an account of quantum mechanics which is particularly local, and which clarifies the nature of information transmission in entangled quantum systems. In this paper, a perspicuous description of their formalism is offered and their claim assessed. It proves essential to distinguish, as Deutsch and Hayden do not, between two ways of interpreting the formalism. On the first, conservative, interpretation, no benefits with respect to locality accrue that are not already available on either an Everettian or a statistical interpretation; and the conclusions regarding information flow are equivocal. The second, ontological, interpretation, offers a framework with the novel feature that global properties of quantum systems are reduced to local ones; but no conclusions follow concerning information flow in more standard quantum mechanics.Comment: 26 pages, LaTeX, uses amsmath; 4 .eps figure

    Entanglement and Relativity

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    In this paper we survey, in an elementary fashion, some of the questions that arise when one considers how entanglement and relativity are related via the notion of non-locality. We begin by reviewing the role of entangled states in Bell inequality violation and question whether the associated notions of non-locality lead to problems with relativity. The use of entanglement and wavefunction collapse in Einstein's famous incompleteness argument is then considered, before we go on to see how the issue of non-locality is transformed if one considers quantum mechanics without collapse to be a complete theory, as in the Everett interpretation. The opportunity is taken to consider whether teleportation and dense coding might constitute a source of non-locality within the Everett interpretation.Comment: 18 pages, uses amsmath, amsfonts, natbib and fancyheadings packages. Typos corrected and additional referenc

    Entanglement without nonlocality

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    We consider the characterization of entanglement from the perspective of a Heisenberg formalism. We derive an original two-party generalized separability criteria, and from this describe a novel physical understanding of entanglement. We find that entanglement may be considered as fundamentally a local effect, and therefore as a separable computational resource from nonlocality. We show how entanglement differs from correlation physically, and explore the implications of this new conception of entanglement for the notion of classicality. We find that this understanding of entanglement extends naturally to multipartite cases.Comment: 9 pages. Expanded introduction and sections on physical entanglement and localit

    Local land preservation in Washington

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    Preserving open space is an important component of growth management policy because protected lands can help shape the patterns of growth. Washington State provides a unique opportunity to analyze the role of local land preservation efforts within a mandated growth management framework to preserve open space and conserve natural resources. The purpose of this study is to evaluate how and why land preservation happens, and the conditions under which some communities preserve more open space than others. This thesis builds on existing research by expanding analysis to smaller communities in the Pacific Northwest. An environmental policy capacity model is used to identify community characteristics potentially affecting conservation efforts as they relate to variations in local land preservation. The degree of association between policy indicators (population density, median household income, education attainment, the number of environmental nonprofit organizations and local land trusts) and policy outcomes (total acreage, percentage of open space and open space per 1,000 residents) is analyzed at the county-level through statistical analysis and a descriptive case study of two rapidly growing counties: Clark and Whatcom. The results suggest environmental nonprofit organizations and local land trusts are significantly associated with protected open space; however, median household income was unexpectedly shown to be negatively correlated. Hence, social capital and civic environmentalism emerge as essential components of successful local land preservation efforts. Many communities continue to face development pressures, and given the competing needs and uses for available land, this research will contribute to ways communities can respond to the land preservation challenge

    Second Amendment Challenges: What Level of Constitutional Scrutiny Applies?

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    Proponents of the Second Amendment stand firm in their belief that there should be little to no restrictions on a person’s ability to obtain and maintain ownership of a gun. Others believe there should be some limitations on the right to “keep and bear arms.” In District of Columbia v. Heller, the Supreme Court upheld a person’s individual right to bear arms for lawful purposes. In Heller, the Court also refused to apply rational basis review to challenges of laws that impact a person’s enumerated rights such as the guarantee against double jeopardy, right to counsel and right to bear arms

    How is there a Physics of Information? On characterising physical evolution as information processing.

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    We have a conundrum. The physical basis of information is clearly a highly active research area. Yet the power of information theory comes precisely from separating it from the detailed problems of building physical systems to perform information processing tasks. Developments in quantum information over the last two decades seem to have undermined this separation, leading to suggestions that information is itself a physical entity and must be part of our physical theories, with resource-cost implications. We will consider a variety of ways in which physics seems to a affect computation, but will ultimately argue to the contrary: rejecting the claims that information is physical provides a better basis for understanding the fertile relationship between information theory and physics. instead, we will argue that the physical resource costs of information processing are to be understood through the need to consider physically embodied agents for whom information processing tasks are performed. Doing so sheds light on what it takes for something to be implementing a computational or information processing task of a given kind

    Information and The Brukner-Zeilinger Interpretation of Quantum Mechanics: A Critical Investigation

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    In Brukner and Zeilinger's interpretation of quantum mechanics, information is introduced as the most fundamental notion and the finiteness of information is considered as an essential feature of quantum systems. They also define a new measure of information which is inherently different from the Shannon information and try to show that the latter is not useful in defining the information content in a quantum object. Here, we show that there are serious problems in their approach which make their efforts unsatisfactory. The finiteness of information does not explain how objective results appear in experiments and what an instantaneous change in the so-called information vector (or catalog of knowledge) really means during the measurement. On the other hand, Brukner and Zeilinger's definition of a new measure of information may lose its significance, when the spin measurement of an elementary system is treated realistically. Hence, the sum of the individual measures of information may not be a conserved value in real experiments.Comment: 20 pages, two figures, last version. Section 4 is replaced by a new argument. Other sections are improved. An appendix and new references are adde

    How is there a Physics of Information? On characterising physical evolution as information processing.

    Get PDF
    We have a conundrum. The physical basis of information is clearly a highly active research area. Yet the power of information theory comes precisely from separating it from the detailed problems of building physical systems to perform information processing tasks. Developments in quantum information over the last two decades seem to have undermined this separation, leading to suggestions that information is itself a physical entity and must be part of our physical theories, with resource-cost implications. We will consider a variety of ways in which physics seems to a affect computation, but will ultimately argue to the contrary: rejecting the claims that information is physical provides a better basis for understanding the fertile relationship between information theory and physics. instead, we will argue that the physical resource costs of information processing are to be understood through the need to consider physically embodied agents for whom information processing tasks are performed. Doing so sheds light on what it takes for something to be implementing a computational or information processing task of a given kind

    "Always paracetamol, they give them paracetamol for everything": a qualitative study examining Eastern European migrants' experiences of the UK health service.

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    BACKGROUND: The enlargement of the European Union since 2004 has led to an increase in the number of Eastern European migrants living in the UK. The health of this group is under-researched though some mixed evidence shows they are at higher risk of certain physical health conditions such as heart attacks, strokes, HIV and alcohol use and have poorer mental health. This is compounded by poor or insecure housing, low pay, isolation and prejudice. We aimed to understand the health needs and health service experiences of the Eastern European population in a town in Northern England. METHODS: Five semi structured one-to-one and small group interviews and five focus groups were conducted with 42 Eastern European participants between June and September 2014. The majority of participants were Polish and other participants were from Belarus, Hungary, Latvia, Russia, Slovakia and Ukraine. The data were analysed using thematic framework analysis. RESULTS: Key findings included a good understanding the UK health service structure and high registration and use of general practice/primary care services. However, overall, there were high levels of dissatisfaction, frustration and distrust in General Practitioners (GP). The majority of participants viewed the GP as unhelpful and dismissive; a barrier to secondary/acute care; reluctant to prescribe antibiotics; and that GPs too often advised them to take paracetamol (acetaminophen) and rest. CONCLUSIONS: Overwhelmingly participants had strong opinions about access to primary care and the role of the general practitioners. Although the design of the UK health service was well understood, participants were unhappy with the system of GP as gatekeeper and felt it inferior to the consumer-focused health systems in their country of origin. More work is needed to promote the importance of self-care, reduce antibiotic and medication use, and to increase trust in the GP
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