10,063 research outputs found

    K-orbit closures on G/B as universal degeneracy loci for flagged vector bundles with symmetric or skew-symmetric bilinear form

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    We use equivariant localization and divided difference operators to determine formulas for the torus-equivariant fundamental cohomology classes of KK-orbit closures on the flag variety G/BG/B, where G = GL(n,\C), and where KK is one of the symmetric subgroups O(n,\C) or Sp(n,\C). We realize these orbit closures as universal degeneracy loci for a vector bundle over a variety equipped with a single flag of subbundles and a nondegenerate symmetric or skew-symmetric bilinear form taking values in the trivial bundle. We describe how our equivariant formulas can be interpreted as giving formulas for the classes of such loci in terms of the Chern classes of the various bundles.Comment: Minor revisions and corrections suggested by referees. Final version, to appear in Transformation Group

    Useful entanglement can be extracted from all nonseparable states

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    We consider entanglement distillation from a single-copy of a multipartite state, and instead of rates we analyze the "quality" of the distilled entanglement. This "quality" is quantified by the fidelity with the GHZ-state. We show that each not fully-separable state σ\sigma can increase the "quality" of the entanglement distilled from other states, no matter how weakly entangled is σ\sigma. We also generalize this to the case where the goal is distilling states different than the GHZ. These results provide new insights on the geometry of the set of separable states and its dual (the set of entanglement witnesses).Comment: 7 page

    Instrument calibrates low gas-rate flowmeters

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    Electronically measuring the transit time of a soap bubble carried by the gas stream between two fixed points in a burette calibrates flowmeters used for measuring low gas-flow rates

    Local unitary invariants for multipartite quantum systems

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    A method is presented to obtain local unitary invariants for multipartite quantum systems consisting of fermions or distinguishable particles. The invariants are organized into infinite families, in particular, the generalization to higher dimensional single particle Hilbert spaces is straightforward. Many well-known invariants and their generalizations are also included.Comment: 13 page

    Accountable Care Organizations in California: Promise and Performance

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    California has more accountable care organizations (ACOs) than any other state in the country, with particularly rapid growth over the past two years. This report introduces new evidence that ACOs improve the quality of care, increase patient satisfaction, and may reduce costs

    Integral Grothendieck-Riemann-Roch theorem

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    We show that, in characteristic zero, the obvious integral version of the Grothendieck-Riemann-Roch formula obtained by clearing the denominators of the Todd and Chern characters is true (without having to divide the Chow groups by their torsion subgroups). The proof introduces an alternative to Grothendieck's strategy: we use resolution of singularities and the weak factorization theorem for birational maps.Comment: 24 page

    Promoting Airport Walking: A Guide

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    A study found that signs placed in the Hartsfield-Jackson Atlanta International Airport to promote passengers walking to airport gates rather than taking shuttles resulted in several hundred more passengers a day choosing to walk (ceiling-mounted infrared sensors were used to count travelers entering and exiting the study location). The project was supported by Kresge and the Centers for Disease Control and Prevention. The study also produced a guide, "Promoting Airport Walking," intended primarily for airport managers who want their airports to encourage healthy habits and improve customer experiences

    Superbroadcasting of mixed states

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    We derive the optimal universal broadcasting for mixed states of qubits. We show that the nobroadcasting theorem cannot be generalized to more than a single input copy. Moreover, for four or more input copies it is even possible to purify the input states while broadcasting. We name such purifying broadcasting superbroadcasting.Comment: 4 pages, 4 figures, to appear on Phys. Rev. Let

    Blurring the Boundary: Reinvigorating Joy in the Mundane through Juxtaposition

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    There is an inherent tension between interior and exterior as experienced by the human body. We live an overwhelming majority of our lives indoors, yet we are consistently compelled towards the natural world. This compulsion is necessitated by biophilia, driving a desire to be around lifelike processes. The boundary between interior and exterior mandates that we live our lives on one side or the other at a time, never simultaneously existing both indoors and outdoors. A disparity between the spaces is therefore maintained by the boundary. This perpetual separation sets up for the perfect use of juxtaposition, which is utilized by artists to reinvigorate observational skills and guide viewers to rediscover joy in mundane experience. Visual art is the most conducive to this means of communication, as it allows the viewer to take a cyclical approach to information rather than forcing it into a standardized structure. Artists who take a critical eye to the standardization of presentation and violate the traditional methods of gallery display encourage a viewer to approach experience from a novel perspective, especially that of a domestic nature. Through a manipulation of perspective, the usual becomes unusual and mundane experience elicits a newfound sense of joy
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