343,053 research outputs found

    Technology transfer and cultural exchange: Western scientists and engineers encounter late Tokugawa and Meiji Japan

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    [FIRST PARAGRAPH] During the last decade of the nineteenth century, the Engineer was only one of many British and American publications that took an avid interest in the rapid rise of Japan to the status of a fully industrialized imperial power on a par with major European nations. In December 1897 this journal published a photographic montage of "Pioneers of Modem Engineering Education in Japan" (Figure I), showing a selection of the Japanese and Western teachers who had worked to bring about this singular transformation.' The predominance of Japanese figures in this representation is highly significant: it is an acknowledgment by British observers that the industrialization of Japan-the "Britain of the East"-was not a feat accomplished solely by Western experts who transferred their science and technology to passive Japanese recipients. Yet in focusing primarily on native teachers active in Japan after 1880, this image excludes several of the very foreigners who had trained this indigenous workforce in the preceding decade. Rather than attempting to assess the careers of each of the many international experts involved in Western encounters with Japan before and after the Meiji restoration in 1868, we will focus on disaggregating the highly individualized responses of just some of the Englishspeaking characters. In documenting their diverse encounters with Japanese people and technologies, we will look at the complex phenomena of cultural exchange in which they participated, not always without chauvinism or resistance

    Globular cluster systems in fossil groups: NGC6482, NGC1132 and ESO306-017

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    We study the globular cluster (GC) systems in three representative fossil group galaxies: the nearest (NGC6482), the prototype (NGC1132) and the most massive known to date (ESO306-017). This is the first systematic study of GC systems in fossil groups. Using data obtained with the Hubble Space Telescope Advanced Camera for Surveys in the F475W and F850LP filters, we determine the GC color and magnitude distributions, surface number density profiles, and specific frequencies. In all three systems, the GC color distribution is bimodal, the GCs are spatially more extended than the starlight, and the red population is more concentrated than the blue. The specific frequencies seem to scale with the optical luminosities of the central galaxy and span a range similar to that of the normal bright elliptical galaxies in rich environments. We also analyze the galaxy surface brightness distributions to look for deviations from the best-fit S\'ersic profiles; we find evidence of recent dynamical interaction in all three fossil group galaxies. Using X-ray data from the literature, we find that luminosity and metallicity appear to correlate with the number of GCs and their mean color, respectively. Interestingly, although NGC6482 has the lowest mass and luminosity in our sample, its GC system has the reddest mean color, and the surrounding X-ray gas has the highest metallicity.Comment: 16 pages, 13 figures. Accepted for publication in A&

    Persistent current formation in a high-temperature Bose-Einstein condensate: an experimental test for c-field theory

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    Experimental stirring of a toroidally trapped Bose-Einstein condensate at high temperature generates a disordered array of quantum vortices that decays via thermal dissipation to form a macroscopic persistent current [T. W. Neely em et al. arXiv:1204.1102 (2012)]. We perform 3D numerical simulations of the experimental sequence within the Stochastic Projected Gross-Pitaevskii equation using ab initio determined reservoir parameters. We find that both damping and noise are essential for describing the dynamics of the high-temperature Bose field. The theory gives a quantitative account of the formation of a persistent current, with no fitted parameters.Comment: v2: 7 pages, 3 figures, new experimental data and numerical simulation

    Symptomatic adrenal insufficiency during inhaled corticosteroid treatment

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    Symptomatic adrenal insufficiency, presenting as hypoglycaemia or poor weight gain, may occur on withdrawal of corticosteroid treatment but has not previously been reported during inhaled corticosteroid treatment. This case series illustrates the occurence of clinically significant adrenal insufficiency in asthmatic children while patients were on inhaled corticosteroid treatment and the unexpected modes of presentation. General practitioners and paediatricians need to be aware that this unusual but acute serious complication may occur in patients treated

    Tensor network states and geometry

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    Tensor network states are used to approximate ground states of local Hamiltonians on a lattice in D spatial dimensions. Different types of tensor network states can be seen to generate different geometries. Matrix product states (MPS) in D=1 dimensions, as well as projected entangled pair states (PEPS) in D>1 dimensions, reproduce the D-dimensional physical geometry of the lattice model; in contrast, the multi-scale entanglement renormalization ansatz (MERA) generates a (D+1)-dimensional holographic geometry. Here we focus on homogeneous tensor networks, where all the tensors in the network are copies of the same tensor, and argue that certain structural properties of the resulting many-body states are preconditioned by the geometry of the tensor network and are therefore largely independent of the choice of variational parameters. Indeed, the asymptotic decay of correlations in homogeneous MPS and MERA for D=1 systems is seen to be determined by the structure of geodesics in the physical and holographic geometries, respectively; whereas the asymptotic scaling of entanglement entropy is seen to always obey a simple boundary law -- that is, again in the relevant geometry. This geometrical interpretation offers a simple and unifying framework to understand the structural properties of, and helps clarify the relation between, different tensor network states. In addition, it has recently motivated the branching MERA, a generalization of the MERA capable of reproducing violations of the entropic boundary law in D>1 dimensions.Comment: 18 pages, 18 figure

    The nuclear Schiff moment and time invariance violation in atoms

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    Parity and time invariance violating (P,T-odd) nuclear forces produce P,T-odd nuclear moments. In turn, these moments can induce electric dipole moments (EDMs) in atoms through the mixing of electron wavefunctions of opposite parity. The nuclear EDM is screened by atomic electrons. The EDM of an atom with closed electron subshells is induced by the nuclear Schiff moment. Previously the interaction with the Schiff moment has been defined for a point-like nucleus. No problems arise with the calculation of the electron matrix element of this interaction as long as the electrons are considered to be non-relativistic. However, a more realistic model obviously involves a nucleus of finite-size and relativistic electrons. In this work we have calculated the finite nuclear-size and relativistic corrections to the Schiff moment. The relativistic corrections originate from the electron wavefunctions and are incorporated into a ``nuclear'' moment, which we term the local dipole moment. For mercury these corrections amount to about 25%. We have found that the natural generalization of the electrostatic potential of the Schiff moment for a finite-size nucleus corresponds to an electric field distribution which, inside the nucleus, is well approximated as constant and directed along the nuclear spin, and outside the nucleus is zero. Also in this work the plutonium atomic EDM is estimated.Comment: 16 pages, 1 figure, minor misprints correcte

    Quantum computation with mesoscopic superposition states

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    We present a strategy to engineer a simple cavity-QED two-bit universal quantum gate using mesoscopic distinct quantum superposition states. The dissipative effect on decoherence and amplitude damping of the quantum bits are analyzed and the critical parameters are presented.Comment: 9 pages, 5 Postscript and 1 Encapsulated Postscript figures. To be published in Phys. Rev.

    Characterizing mixing and measurement in quantum mechanics

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    What fundamental constraints characterize the relationship between a mixture ρ=ipiρi\rho = \sum_i p_i \rho_i of quantum states, the states ρi\rho_i being mixed, and the probabilities pip_i? What fundamental constraints characterize the relationship between prior and posterior states in a quantum measurement? In this paper we show that there are many surprisingly strong constraints on these mixing and measurement processes that can be expressed simply in terms of the eigenvalues of the quantum states involved. These constraints capture in a succinct fashion what it means to say that a quantum measurement acquires information about the system being measured, and considerably simplify the proofs of many results about entanglement transformation.Comment: 12 page

    Entanglement Manipulation and Concentration

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    We introduce a simple, experimentally realisable, entanglement manipulation protocol for exploring mixed state entanglement. We show that for both non-maximally entangled pure, and mixed polarisation-entangled two qubit states, an increase in the degree of entanglement and purity, which we define as concentration, is achievable.Comment: Accepted as Rapid Communication PR

    Quantum and classical fidelities for Gaussian states

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    We examine the physical significance of fidelity as a measure of similarity for Gaussian states, by drawing a comparison with its classical counterpart. We find that the relationship between these classical and quantum fidelities is not straightforward, and in general does not seem to provide insight into the physical significance of quantum fidelity. To avoid this ambiguity we propose that the efficacy of quantum information protocols be characterized by determining their transfer function and then calculating the fidelity achievable for a hypothetical pure reference input state.Comment: 9 pages, 5 figures, to be published in J. Opt. Soc. Am. B special issue on Optical Quantum Information Scienc
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