3,639 research outputs found

    Exact Dynamical Correlation Functions of Calogero-Sutherland Model and One-Dimensional Fractional Statistics

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    One-dimensional model of non-relativistic particles with inverse-square interaction potential known as Calogero-Sutherland Model (CSM) is shown to possess fractional statistics. Using the theory of Jack symmetric polynomial the exact dynamical density-density correlation function and the one-particle Green's function (hole propagator) at any rational interaction coupling constant λ=p/q\lambda = p/q are obtained and used to show clear evidences of the fractional statistics. Motifs representing the eigenstates of the model are also constructed and used to reveal the fractional {\it exclusion} statistics (in the sense of Haldane's ``Generalized Pauli Exclusion Principle''). This model is also endowed with a natural {\it exchange } statistics (1D analog of 2D braiding statistics) compatible with the {\it exclusion} statistics. (Submitted to PRL on April 18, 1994)Comment: Revtex 11 pages, IASSNS-HEP-94/27 (April 18, 1994

    Search for Point Sources of Ultra-High Energy Cosmic Rays Above 40 EeV Using a Maximum Likelihood Ratio Test

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    We present the results of a search for cosmic ray point sources at energies above 40 EeV in the combined data sets recorded by the AGASA and HiRes stereo experiments. The analysis is based on a maximum likelihood ratio test using the probability density function for each event rather than requiring an a priori choice of a fixed angular bin size. No statistically significant clustering of events consistent with a point source is found.Comment: 7 pages, 7 figures. Accepted for publication in The Astrophysical Journa

    Classical and Quantum Nambu Mechanics

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    The classical and quantum features of Nambu mechanics are analyzed and fundamental issues are resolved. The classical theory is reviewed and developed utilizing varied examples. The quantum theory is discussed in a parallel presentation, and illustrated with detailed specific cases. Quantization is carried out with standard Hilbert space methods. With the proper physical interpretation, obtained by allowing for different time scales on different invariant sectors of a theory, the resulting non-Abelian approach to quantum Nambu mechanics is shown to be fully consistent.Comment: 44 pages, 1 figure, 1 table Minor changes to conform to journal versio

    Search for Correlations between HiRes Stereo Events and Active Galactic Nuclei

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    We have searched for correlations between the pointing directions of ultrahigh energy cosmic rays observed by the High Resolution Fly's Eye experiment and Active Galactic Nuclei (AGN) visible from its northern hemisphere location. No correlations, other than random correlations, have been found. We report our results using search parameters prescribed by the Pierre Auger collaboration. Using these parameters, the Auger collaboration concludes that a positive correlation exists for sources visible to their southern hemisphere location. We also describe results using two methods for determining the chance probability of correlations: one in which a hypothesis is formed from scanning one half of the data and tested on the second half, and another which involves a scan over the entire data set. The most significant correlation found occurred with a chance probability of 24%.Comment: 13 pages, 1 table, 5 figure

    Institutional legacies and HRM: similarities and differences in HRM practices in Portugal and Mozambique

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    This is a study of institutional change and continuity, comparing the trajectories followed by Mozambique and its formal colonial power Portugal in HRM, based on two surveys of firm level practices. The colonial power sought to extend the institutions of the metropole in the closing years of its rule, and despite all the adjustments and shocks that have accompanied Mozambique’s post-independence years, the country continues to retain institutional features and associated practices from the past. This suggests that there is a post-colonial impact on human resource management. The implications for HRM theory are that ambitious attempts at institutional substitution may have less dramatic effects than is commonly assumed. Indeed, we encountered remarkable similarities between the two countries in HRM practices, implying that features of supposedly fluid or less mature institutional frameworks (whether in Africa or the Mediterranean world) may be sustained for protracted periods of time, pressures to reform notwithstanding. This highlights the complexities of continuities which transcend formal rules; as post-colonial theories alert us, informal conventions and embedded discourse may result in the persistence of informal power and subordination, despite political and legal changes

    PHEMTO: the polarimetric high energy modular telescope observatory

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    Based upon dual focusing techniques, the Polarimetric High-Energy Modular Telescope Observatory (PHEMTO) is designed to have performance several orders of magnitude better than the present hard X-ray instruments, in the 1–600 keV energy range. This, together with its angular resolution of around one arcsecond, and its sensitive polarimetry measurement capability, will give PHEMTO the improvements in scientific performance needed for a mission in the 2050 era in order to study AGN, galactic black holes, neutrons stars, and supernovae. In addition, its high performance will enable the study of the non-thermal processes in galaxy clusters with an unprecedented accuracy.Open access funding provided by Istituto Nazionale di Astrofisica within the CRUI-CARE Agreement

    Hopf algebras and Markov chains: Two examples and a theory

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    The operation of squaring (coproduct followed by product) in a combinatorial Hopf algebra is shown to induce a Markov chain in natural bases. Chains constructed in this way include widely studied methods of card shuffling, a natural "rock-breaking" process, and Markov chains on simplicial complexes. Many of these chains can be explictly diagonalized using the primitive elements of the algebra and the combinatorics of the free Lie algebra. For card shuffling, this gives an explicit description of the eigenvectors. For rock-breaking, an explicit description of the quasi-stationary distribution and sharp rates to absorption follow.Comment: 51 pages, 17 figures. (Typographical errors corrected. Further fixes will only appear on the version on Amy Pang's website, the arXiv version will not be updated.
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