947 research outputs found

    Collective Oscillations of an Imbalanced Fermi Gas: Axial Compression Modes and Polaron Effective Mass

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    We investigate the low-lying compression modes of a unitary Fermi gas with imbalanced spin populations. For low polarization, the strong coupling between the two spin components leads to a hydrodynamic behavior of the cloud. For large population imbalance we observe a decoupling of the oscillations of the two spin components, giving access to the effective mass of the Fermi polaron, a quasi-particle composed of an impurity dressed by particle-hole pair excitations in a surrounding Fermi sea. We find m∗/m=1.17(10)m^*/m=1.17(10), in agreement with the most recent theoretical predictions.Comment: 4 pages, 4 figures, submitted to PR

    Novel mutations in the anoctamin 5 gene ( ANO5 ) associated with limb‐girdle muscular dystrophy 2L

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    Introduction: We present a Jordanian man with the typical LGMD 2L phenotype of early, asymmetric quadriceps weakness and subsequent biceps brachii weakness. Methods: Case report. Results: Muscle biopsies document a progressive dystrophic pattern unrelated to known sarcolemmal defects associated with muscular dystrophy. Genetic testing revealed novel, heterozygote Anoctamin 5 gene mutations. Conclusions: This case report expands the known mutations resulting in LGMD 2L and supports the assertion that Anoctamin 5 mutations are more prevalent than previously recognized. Muscle Nerve, 2013Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96310/1/23542_ftp.pd

    Dynamics of a tunable superfluid junction

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    We study the population dynamics of a Bose-Einstein condensate in a double-well potential throughout the crossover from Josephson dynamics to hydrodynamics. At barriers higher than the chemical potential, we observe slow oscillations well described by a Josephson model. In the limit of low barriers, the fundamental frequency agrees with a simple hydrodynamic model, but we also observe a second, higher frequency. A full numerical simulation of the Gross-Pitaevskii equation giving the frequencies and amplitudes of the observed modes between these two limits is compared to the data and is used to understand the origin of the higher mode. Implications for trapped matter-wave interferometers are discussed.Comment: 8 pages, 7 figures; v3: Journal reference added, minor changes to tex

    Asexuality

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    Asexuality is overlooked in the philosophical literature and in wider society. Such neglect produces incomplete or inaccurate accounts of romantic life and harms asexual people. We develop an account of asexuality to redress this neglect and enrich discussion of romantic life. Asexual experiences are diverse. Some asexual people have sex; some have romantic relationships in the absence of sex. We accept the common definition of asexuality as the absence of sexual attraction and explain how sexual attraction and sexual desire differ by giving an affordance‐like account of sexual attraction. Armed with that distinction, we show that asexuality is clearly different from celibacy or disorders of desire and that some existing philosophical theories of sexual desire struggle to accommodate asexual sexuality. We then build on asexual testimony about the diversity of non‐sexual attractions to answer two common objections levelled at asexual romance: that romantic relationships require sexual attraction or that sex in the absence of sexual attraction is insufficiently focused on someone as an individual. Finally, we describe some of the ways asexuality has been erased or denigrated in society, and the specific injustices and harms that result

    Red Giant Eclipsing Binaries: Exploring Non-Oscillators and Testing Asteroseismic Scalings

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    Thanks to advances in asteroseismology, red giants have become astrophysical laboratories for probing the Milky Way. Eclipsing binaries allow us to directly measure stellar properties independently of asteroseismology, which we use to investigate why some red giants don't oscillate and test asteroseismic scaling relations for those that do. By combining orbital solutions, high-resolution spectroscopy, and stellar evolution models for a subset of eight eclipsing red giants observed by Kepler, we find short-period binaries with strong tidal forces and systems with active red giants are less likely to exhibit solar-like oscillations. We also preview the results from Gaulme et al. 2016 (submitted). We find asteroseismic scalings overestimate red giant radii by about 6% on average and masses by about 16% in ten systems observed by Kepler. Systematic overestimation of mass leads to underestimation of stellar age, which has important implications for ensemble asteroseismology applied to galactic studies

    Theory of Photon Blockade by an Optical Cavity with One Trapped Atom

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    In our recent paper [1], we reported observations of photon blockade by one atom strongly coupled to an optical cavity. In support of these measurements, here we provide an expanded discussion of the general phenomenology of photon blockade as well as of the theoretical model and results that were presented in Ref. [1]. We describe the general condition for photon blockade in terms of the transmission coefficients for photon number states. For the atom-cavity system of Ref. [1], we present the model Hamiltonian and examine the relationship of the eigenvalues to the predicted intensity correlation function. We explore the effect of different driving mechanisms on the photon statistics. We also present additional corrections to the model to describe cavity birefringence and ac-Stark shifts. [1] K. M. Birnbaum, A. Boca, R. Miller, A. D. Boozer, T. E. Northup, and H. J. Kimble, Nature 436, 87 (2005).Comment: 10 pages, 6 figure

    Anti–3‐hydroxy‐3‐methylglutaryl‐coenzyme a reductase autoantibody‐positive necrotizing autoimmune myopathy with dermatomyositis‐like eruption

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143804/1/mus26072.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143804/2/mus26072_am.pd
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