4,703 research outputs found

    Entanglement Generation from Thermal Spin States via Unitary Beam Splitters

    Full text link
    We suggest a method of generating distillable entanglement form mixed states unitarily, by utilizing the flexibility of dimension od occupied Hilbert space. We present a model of a thermal spin state entering a beam splitter generating entanglement. It is the truncation of the state that allows for entanglement generation. The output entanglement is investigated for different temperatures and it is found that more randomness - in the form of higher temperature - is better for this set up.Comment: 4 pages, 3 figures. Small changes in accordance with journal advice to make more readable. Improved discussion on implemetability of scheme, and references adde

    Entanglement of multiparty stabilizer, symmetric, and antisymmetric states

    Get PDF
    We study various distance-like entanglement measures of multipartite states under certain symmetries. Using group averaging techniques we provide conditions under which the relative entropy of entanglement, the geometric measure of entanglement and the logarithmic robustness are equivalent. We consider important classes of multiparty states, and in particular show that these measures are equivalent for all stabilizer states, symmetric basis and antisymmetric basis states. We rigorously prove a conjecture that the closest product state of permutation symmetric states can always be chosen to be permutation symmetric. This allows us to calculate the explicit values of various entanglement measures for symmetric and antisymmetric basis states, observing that antisymmetric states are generally more entangled. We use these results to obtain a variety of interesting ensembles of quantum states for which the optimal LOCC discrimination probability may be explicitly determined and achieved. We also discuss applications to the construction of optimal entanglement witnesses

    The 30/20 GHz communications system functional requirements

    Get PDF
    The characteristics of 30/20 GHz usage in satellite systems to be used in support of projected communication requirements of the 1990's are defined. A requirements analysis which develops projected market demand for satellite services by general and specialized carriers and an analysis of the impact of propagation and system constraints on 30/20 GHz operation are included. A set of technical performance characteristics for the 30/20 GHz systems which can serve the resulting market demand and the experimental program necessary to verify technical and operational aspects of the proposed systems is also discussed

    Thermal robustness of multipartite entanglement of the 1-D spin 1/2 XY model

    Full text link
    We study the robustness of multipartite entanglement of the ground state of the one-dimensional spin 1/2 XY model with a transverse magnetic field in the presence of thermal excitations, by investigating a threshold temperature, below which the thermal state is guaranteed to be entangled. We obtain the threshold temperature based on the geometric measure of entanglement of the ground state. The threshold temperature reflects three characteristic lines in the phase diagram of the correlation function. Our approach reveals a region where multipartite entanglement at zero temperature is high but is thermally fragile, and another region where multipartite entanglement at zero temperature is low but is thermally robust.Comment: Revised, 11 pages, 7 figure

    Man, Nature, and New Ideas: The Legacy of Sea Pines Plantation

    Get PDF
    My goal is to learn the history of Hilton Head Island and logically reason out the way it grew, marking Sea Pine’s design influence over time and place. This paper is meant to be a piece of nature and history writing, which has implications for the study of environmental economics and real-estate design practices, but is not strictly about either. The thrust of this piece is the mapping of developmental philosophies and their reflection in the land. This topic interests me because at its core, it looks at how decisions are made, and the trade offs that influence them. The paper is also about the formation of ideas that explore sustainable forms of human-environment interaction, but which do not give up the high quality of life that modern man has come to expect. Environmental issues will continue to influence social, economic and political thought as we move towards midcentury. Sea Pines champions a blending of man and nature that may be able to provide alternative and more efficient solutions to the problems that our society faces

    Survival of entanglement in thermal states

    Full text link
    We present a general sufficiency condition for the presence of multipartite entanglement in thermal states stemming from the ground state entanglement. The condition is written in terms of the ground state entanglement and the partition function and it gives transition temperatures below which entanglement is guaranteed to survive. It is flexible and can be easily adapted to consider entanglement for different splittings, as well as be weakened to allow easier calculations by approximations. Examples where the condition is calculated are given. These examples allow us to characterize a minimum gapping behavior for the survival of entanglement in the thermodynamic limit. Further, the same technique can be used to find noise thresholds in the generation of useful resource states for one-way quantum computing.Comment: 6 pages, 2 figures. Changes made in line with publication recommendations. Motivation and concequences of result clarified, with the addition of one more example, which applies the result to give noise thresholds for measurement based quantum computing. New author added with new result

    Relationships between scores on the Jefferson Scale of physician empathy, patient perceptions of physician empathy, and humanistic approaches to patient care: a validity study.

    Get PDF
    BACKGROUND: Empathy is the backbone of a positive physician-patient relationship. Physician empathy and the patient\u27s awareness of the physician\u27s empathic concern can lead to a more positive clinical outcome. MATERIAL/METHODS: The Jefferson Scale of Physician Empathy (JSPE) was completed by 36 physicians in the Family Medicine residency program at Thomas Jefferson University Hospital, and 90 patients evaluated these physicians by completing the Jefferson Scale of Patient Perceptions of Physician Empathy (JSPPPE), and a survey about physicians\u27 humanistic approaches to patient care. RESULTS: A statistically significant correlation was found between scores of the JSPE and JSPPPE (r=0.48, p CONCLUSIONS: These findings provide further support for the validity of the JSPE. Implications for the assessments of empathy in the physician-patient relationship as related to clinical outcomes are discussed

    The EU and the Rights of the Roma: How Could the EU have Changed the French Repatriation Program of 2010?

    Get PDF
    In August of 2010, the French government began a program of deporting those Roma who lived within the country. Under European Union (EU) law, mass expulsions based on ethnicity are forbidden, as are mass examinations of peoples as opposed to individual assessments in the case of a crime. However, in the spirit of egalitarianism, France does not acknowledge the idea of racial or ethnic minorities. Instead, they have reframed the non- French Roma as a group engaged in criminal activity following Italy’s “security package” of 2008, which described ‘nomads’ as a national security threat and created legislation leading to expulsions of non-Italian Roma. By framing the Roma as a criminal group as opposed to an ethnic minority (that may be engaging in criminal activity), France is able to justify its actions in targeting the Roma people writ large instead of looking at each criminal case on a case-by-case basis. My resulting research question is: if we assume that the Roma are an ethnic minority in France, what obligations does the EU have in enforcing their rights in a member state that does not acknowledge the concept of “ethnic minority”? This paper will look at the French repatriation program and use Critical Race Theory as a framework to critique the situation and examine how EU-level policy could change the position of the Roma in France

    New Protocols and Lower Bound for Quantum Secret Sharing with Graph States

    Full text link
    We introduce a new family of quantum secret sharing protocols with limited quantum resources which extends the protocols proposed by Markham and Sanders and by Broadbent, Chouha, and Tapp. Parametrized by a graph G and a subset of its vertices A, the protocol consists in: (i) encoding the quantum secret into the corresponding graph state by acting on the qubits in A; (ii) use a classical encoding to ensure the existence of a threshold. These new protocols realize ((k,n)) quantum secret sharing i.e., any set of at least k players among n can reconstruct the quantum secret, whereas any set of less than k players has no information about the secret. In the particular case where the secret is encoded on all the qubits, we explore the values of k for which there exists a graph such that the corresponding protocol realizes a ((k,n)) secret sharing. We show that for any threshold k> n-n^{0.68} there exists a graph allowing a ((k,n)) protocol. On the other hand, we prove that for any k< 79n/156 there is no graph G allowing a ((k,n)) protocol. As a consequence there exists n_0 such that the protocols introduced by Markham and Sanders admit no threshold k when the secret is encoded on all the qubits and n>n_0

    Neither playing the game nor keeping it real: media logics and Big Brother

    Get PDF
    Sam Pepper, one of the contestants in Big Brother 11, at one point accused fellow housemates Josie and John James of feigning romantic feelings for each other in order to cash in on lucrative deals with celebrity magazines such as OK! and Hello!. The provocation caused much apparent offence, and led to a prolonged and predominantly rancorous debate about authenticity and inauthenticity, soon extending to revelations that other housemates (Rachel, Corinne) aimed to appear in soft pornography titles like Nuts and Zoo, and as such, ‘couldn’t be trusted’. The clear subtext was that any economic motivation was considered a breach of the rules of the Big Brother game – not the explicit parameters of the competition, but the spirit in which it should be played. Being a worthy winner is a matter of who you are rather than what you do, which raises the question of how we came to know Josie and co, as well as how we come to know celebrity selves generally. If BB has taught us anything about the formation of mediated selves, it is that an authentic mediated self cannot exist – and yet authenticity still matters. This piece reflects on this tension and its implications for our increasingly reflexive media culture
    corecore