7,775 research outputs found

    Parastatistics of charged bosons partly localised by impurities

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    Coulomb repulsion is taken into account to derive the thermodynamics of charged bosons in a random external potential. A simple analytical form of the partition function is proposed for the case of non-overlapping localised states (i.e. a small amount of disorder). The density of localised bosons and the specific heat show a peculiar non-uniform temperature dependence below the Bose-Einstein condensation temperature. The superfluid - Bose-glass phase diagram is discussed. A new phase is predicted which is a Bose-glass at T=0 but a superfluid at finite T.Comment: 6 pages, Revtex, 6 figures (available on request from the authors

    SPAR data handling utilities

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    The SPAR computer software system is a collection of processors that perform particular steps in the finite-element structural analysis procedure. The data generated by each processor are stored on a data base complex residing on an auxiliary storage device, and these data are then used by subsequent processors. The SPAR data handling utilities use routines to transfer data between the processors and the data base complex. A detailed description of the data base complex organization is presented. A discussion of how these SPAR data handling utilities are used in an application program to perform desired user functions is given with the steps necessary to convert an existing program to a SPAR processor by incorporating these utilities. Finally, a sample SPAR processor is included to illustrate the use of the data handling utilities

    A Deep Relevance Matching Model for Ad-hoc Retrieval

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    In recent years, deep neural networks have led to exciting breakthroughs in speech recognition, computer vision, and natural language processing (NLP) tasks. However, there have been few positive results of deep models on ad-hoc retrieval tasks. This is partially due to the fact that many important characteristics of the ad-hoc retrieval task have not been well addressed in deep models yet. Typically, the ad-hoc retrieval task is formalized as a matching problem between two pieces of text in existing work using deep models, and treated equivalent to many NLP tasks such as paraphrase identification, question answering and automatic conversation. However, we argue that the ad-hoc retrieval task is mainly about relevance matching while most NLP matching tasks concern semantic matching, and there are some fundamental differences between these two matching tasks. Successful relevance matching requires proper handling of the exact matching signals, query term importance, and diverse matching requirements. In this paper, we propose a novel deep relevance matching model (DRMM) for ad-hoc retrieval. Specifically, our model employs a joint deep architecture at the query term level for relevance matching. By using matching histogram mapping, a feed forward matching network, and a term gating network, we can effectively deal with the three relevance matching factors mentioned above. Experimental results on two representative benchmark collections show that our model can significantly outperform some well-known retrieval models as well as state-of-the-art deep matching models.Comment: CIKM 2016, long pape

    Universality and Clustering in 1+1 Dimensional Superstring-Bit Models

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    We construct a 1+1 dimensional superstring-bit model for D=3 Type IIB superstring. This low dimension model escapes the problems encountered in higher dimension models: (1) It possesses full Galilean supersymmetry; (2) For noninteracting polymers of bits, the exactly soluble linear superpotential describing bit interactions is in a large universality class of superpotentials which includes ones bounded at spatial infinity; (3) The latter are used to construct a superstring-bit model with the clustering properties needed to define an SS-matrix for closed polymers of superstring-bits.Comment: 11 pages, Latex documen

    Is Tsallis thermodynamics nonextensive?

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    Within the Tsallis thermodynamics' framework, and using scaling properties of the entropy, we derive a generalization of the Gibbs-Duhem equation. The analysis suggests a transformation of variables that allows standard thermodynamics to be recovered. Moreover, we also generalize Einstein's formula for the probability of a fluctuation to occur by means of the maximum statistical entropy method. The use of the proposed transformation of variables also shows that fluctuations within Tsallis statistics can be mapped to those of standard statistical mechanics.Comment: 4 pages, no figures, revised version, new title, accepted in PR

    Particle Physics in the LHC era

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    This book gives a modern introduction to particle physics. The main mathematical tools required for the rest of the book are developed in Chapter 2. A quantitative introduction to accelerator physics is presented in Chapter 3. Chapter 4 covers detector physics, with an emphasis on fundamental physical principles. Chapter 5 covers the static quark model, with applications to light mesons and baryons as well as heavier states containing charm and beauty quarks. Chapter 6 introduces relativistic quantum mechanics and uses spinors to relate Lorentz invariance to the Dirac equation. Chapter 7 covers the basics of the electroweak theory based on broken SU(2) Ă— U(1) symmetry. Chapter 8 reviews some of the key experiments that led to the development of the electroweak theory. Chapter 9 explains the importance of deep inelastic scattering data for providing direct evidence for the existence of quarks. It also gives a brief introduction to quantum chromodynamics (QCD). Chapter 10 considers flavour oscillations in the quark sector and then discusses the evidence for CP violation. Chapter 11 examines the theory of neutrino oscillations as well as the evidence for these oscillations. Chapter 12 gives an elementary introduction to the Higgs mechanism as well as a careful explanation of the experimental evidence for the existence of a Higgs boson. Chapter 13 looks at LHC physics and explains how searches for Beyond the Standard Model Physics are performed. It concludes with a discussion of the evidence for dark matter and dark energy

    Particle Physics in the LHC era

    Get PDF
    This book gives a modern introduction to particle physics. The main mathematical tools required for the rest of the book are developed in Chapter 2. A quantitative introduction to accelerator physics is presented in Chapter 3. Chapter 4 covers detector physics, with an emphasis on fundamental physical principles. Chapter 5 covers the static quark model, with applications to light mesons and baryons as well as heavier states containing charm and beauty quarks. Chapter 6 introduces relativistic quantum mechanics and uses spinors to relate Lorentz invariance to the Dirac equation. Chapter 7 covers the basics of the electroweak theory based on broken SU(2) Ă— U(1) symmetry. Chapter 8 reviews some of the key experiments that led to the development of the electroweak theory. Chapter 9 explains the importance of deep inelastic scattering data for providing direct evidence for the existence of quarks. It also gives a brief introduction to quantum chromodynamics (QCD). Chapter 10 considers flavour oscillations in the quark sector and then discusses the evidence for CP violation. Chapter 11 examines the theory of neutrino oscillations as well as the evidence for these oscillations. Chapter 12 gives an elementary introduction to the Higgs mechanism as well as a careful explanation of the experimental evidence for the existence of a Higgs boson. Chapter 13 looks at LHC physics and explains how searches for Beyond the Standard Model Physics are performed. It concludes with a discussion of the evidence for dark matter and dark energy

    Operation without Operators

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    Construction of bosonic string theory on infinitely curved Anti-de Sitter space

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    Free scalar field theory in the sector with a large number of particles can be interpreted as bosonic string theory on anti-de Sitter space of vanishing radius. Different ways of writing the field theory Hamiltonian translate to different ways of reparametrizing the world-sheet sigma coordinate. Adding a mass term in the field theory corresponds to cutting off the warped AdS direction, with cut-off inversely proportional to the mass. The string theory has neither tachyon, nor critical dimension.Comment: 18 pages, latex, using revte

    On the structure of the space of generalized connections

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    We give a modern account of the construction and structure of the space of generalized connections, an extension of the space of connections that plays a central role in loop quantum gravity.Comment: 30 pages, added references, minor changes. To appear in International Journal of Geometric Methods in Modern Physic
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