286 research outputs found

    Peripheral fillings of relatively hyperbolic groups

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    A group theoretic version of Dehn surgery is studied. Starting with an arbitrary relatively hyperbolic group GG we define a peripheral filling procedure, which produces quotients of GG by imitating the effect of the Dehn filling of a complete finite volume hyperbolic 3--manifold MM on the fundamental group π1(M)\pi_1(M). The main result of the paper is an algebraic counterpart of Thurston's hyperbolic Dehn surgery theorem. We also show that peripheral subgroups of GG 'almost' have the Congruence Extension Property and the group GG is approximated (in an algebraic sense) by its quotients obtained by peripheral fillings. Various applications of these results are discussed.Comment: The difference with the previous version is that Proposition 3.2 is proved for quasi--geodesics instead of geodesics. This allows to simplify the exposition in the last section. To appear in Invent. Mat

    The electrical properties of coating obtained by vacuum arc deposition

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    AbstractThis paper investigates the electrical properties of the coating based on Ti–C–B system. The coating was obtained by vacuum-arc method by spraying of multi compound cathode prepared by reactive hot pressing of Ti, carbon black and amorphous B powder mixture.The electrical conductivity of the coating was measured in temperature range of 10–320K which was about σ=4.8·103Ω−1cm−1 in the entire temperature range. The carrier concentration measured was about n=1·1022 cm−3. The charge carriers’ mobility varies between 10 and −7 and changes sign at temperature about T=225K

    Low-Molecular Weight Cow Colostrum Components in Functional Nutrition

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    Background: The concept of functional nutrition has been actively developed in recent years. LMWCC contains biologically active compounds of natural origin and can be promising components of functional nutrition.Methods: Wistar rats (intact, rats with Cu-induced toxicosis and rats with Cu-induced toxicosis, who received LMWCC per os in different doses of 0.01, 0.05, 0.1, 1, 2, 3 mg / 100 g of body weight of the animal). The effect of low-molecular weight components of cow colostrum (LMWCC) have been studied on the some physiological and biochemical parameters (body weight, temperature, ability to perform work, activity of aspartate aminotransferase, alanine aminotransferase, cholesterol, triacylglycerides, creatinine, albumin, gamma-glutamyltransferase and lipid hydroperoxides) in experimental animals with Cu -induced toxicosis.Results: It was found that LMWCC in small doses (0.05-0.1 mg / 100 g of weight) restored the growth rate, body temperature and partially working capacity in the test "swimming with a load" of animals with Cu-induced toxicosis. Restoration of physiological parameters in animals with Cu-induced toxemia correlated with activation of the antioxidant enzyme glutathione peroxidase and a decrease in serum hydroperoxides in blood serum.It was suggested that LMWCC can be promising components of functional nutrition for various toxicoses.Conclusions: LMWCC has antioxidant properties in relatively small doses (0.05-0.1 mg / 100 g of weight). Restoration of the physiological characteristics of animals with Cu-induced toxicosis correlates with the elimination of oxidative stress. Large doses of 1 mg / 100 g of body weight and more manifest pro-oxidant properties

    A complete solution of a Constrained System: SUSY Monopole Quantum Mechanics

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    We solve the quantum mechanical problem of a charged particle on S^2 in the background of a magnetic monopole for both bosonic and supersymmetric cases by constructing Hilbert space and realizing the fundamental operators obeying complicated Dirac bracket relations in terms of differential operators. We find the complete energy eigenfunctions. Using the lowest energy eigenstates we count the number of degeneracies and examine the supersymmetric structure of the ground states in detail.Comment: 20 pages including the title, prepared in JHEP forma

    Higher Spins from Tensorial Charges and OSp(N|2n) Symmetry

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    It is shown that the quantization of a superparticle propagating in an N=1, D=4 superspace extended with tensorial coordinates results in an infinite tower of massless spin states satisfying the Vasiliev unfolded equations for free higher spin fields in flat and AdS_4 N=1 superspace. The tensorial extension of the AdS_4 superspace is proved to be a supergroup manifold OSp(1|4). The model is manifestly invariant under an OSp(N|8) (N=1,2) superconformal symmetry. As a byproduct, we find that the Cartan forms of arbitrary Sp(2n) and OSp(1|2n) groups are GL(2n) flat, i.e. they are equivalent to flat Cartan forms up to a GL(2n) rotation. This property is crucial for carrying out the quantization of the particle model on OSp(1|4) and getting the higher spin field dynamics in super AdS_4, which can be performed in a way analogous to the flat case.Comment: LaTeX, 21 page (JHEP style), misprints corrected, added comments on the relation of results of hep-th/0106149 with hep-th/9904109 and hep-th/9907113, references adde

    Topological Superfluid in one-dimensional Ultracold Atomic System with Spin-Orbit Coupling

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    We propose a one-dimensional Hamiltonian H1DH_{1D} which supports Majorana fermions when dx2−y2d_{x^{2}-y^{2}}-wave superfluid appears in the ultracold atomic system and obtain the phase-separation diagrams both for the time-reversal-invariant case and time-reversal-symmetry-breaking case. From the phase-separation diagrams, we find that the single Majorana fermions exist in the topological superfluid region, and we can reach this region by tuning the chemical potential μ\mu and spin-orbit coupling αR\alpha_{R}. Importantly, the spin-orbit coupling has realized in ultracold atoms by the recent experimental achievement of synthetic gauge field, therefore, our one-dimensional ultra-cold atomic system described by H1DH_{1D} is a promising platform to find the mysterious Majorana fermions.Comment: 5 papers, 2 figure

    Electromagnetic form factors of charged and neutral kaons in an extended vector-meson-dominance model

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    A model is developed for electromagnetic form factors of the charged and neutral K-mesons. The formalism is based on ChPT Lagrangians with vector mesons. The form factors, calculated without fitting parameters, are in a good agreement with experiment for space-like and time-like photon momenta. Contribution of the two-kaon channels to the muon anomalous magnetic moment a_\mu is calculated.Comment: 23 pages, 11 figures, accepted for publication in Eur. Phys. J.

    Heavy quarkonium: progress, puzzles, and opportunities

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    A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the BB-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair

    Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

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    Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
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