3,976 research outputs found

    NMR relaxation rate in non-centrosymmetric superconductors

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    The spin-lattice relaxation rate of nuclear magnetic resonance in a clean superconductor without inversion center is calculated for arbitrary pairing symmetry and band structure, in the presence of strong spin-orbit coupling.Comment: 4 page

    Calabi-Yau 3-folds from 2-folds

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    We consider type IIA string theory on a Calabi-Yau 2-fold with D6-branes wrapping 2-cycles in the 2-fold. We find a complete set of conditions on the supergravity solution for any given wrapped brane configuration in terms of SU(2) structures. We reduce the problem of finding a supergravity solution for the wrapped branes to finding a harmonic function on R×\timesCY2_2. We then lift this solution to 11-dimensions as a product of R(4.1)^{(4.1)} and a Calabi-Yau 3-fold. We show how the metric on the 3-fold is determined in terms of the wrapped brane solution. We write down the distinguished (3,0) form and the K{\"a}hler form of the 3-fold in terms of structures defined on the base 2-d complex manifold. We discuss the topology of the 3-fold in terms of the D6-branes and the underlying 2-fold. We show that in addition to the non-trivial cycles inherited from the underlying 2-fold there are N1N-1 new 2-cycles. We construct closed (1,1) forms corresponding to these new cycles. We also display some explicit examples. One of our examples is that of D6-branes wrapping the 2-cycle in an A1_1 ALE space, the resulting 3-fold has h(1,1)=Nh^{(1,1)}=N, where NN is the number of D6-branes.Comment: 30 page

    Spontaneous kidney rupture in polyarteritis nodosa presenting as an acute abdomen

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    CITATION: Edelstein, C. L. & Welke, H. 1991. Spontaneous kidney rupture in polyarteritis nodosa presenting as an acute abdome. South African Medical Journal, 79:52-53.The original publication is available at http://www.samj.org.zaAn acute abdomen in a patient with polyarteritis nodosa (PAN) is a perplexing and challenging problem for both the physician and the surgeon.Publisher’s versio

    Signature of superconducting states in cubic crystal without inversion symmetry

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    The effects of absence of inversion symmetry on superconducting states are investigated theoretically. In particular we focus on the noncentrosymmetric compounds which have the cubic symmetry OO like Li2_2Pt3_3B. An appropriate and isotropic spin-orbital interaction is added in the Hamiltonian and it acts like a magnetic monopole in the momentum space. The consequent pairing wavefunction has an additional triplet component in the pseudospin space, and a Zeeman magnetic field B\bf{B} can induce a collinear supercurrent J\bf{J} with a coefficient κ(T)\kappa(T). The effects of anisotropy embedded in the cubic symmetry and the nodal superconducting gap function on κ(T)\kappa(T) are also considered. From the macroscopic perspectives, the pair of mutually induced J\bf{J} and magnetization M{\bf{M}} can affect the distribution of magnetic field in such noncentrosymmetric superconductors, which is studied through solving the Maxwell equation in the Meissner geometry as well as the case of a single vortex line. In both cases, magnetic fields perpendicular to the external ones emerge as a signature of the broken symmetry.Comment: 16 pages in pre-print forma

    Training New Dental Health Providers in the U.S. (Full Report)

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    This 52 page report explores the interest and need to establish new midlevel dental providers in the U.S. The genesis of this interest is concern about access to care for underserved populations whose higher oral disease rates and unmet oral care needs are well documented.  This document was published December 2009 and updated June 2010

    On the spin susceptibility of noncentrosymmetric superconductors

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    We calculate the spin susceptibility of a superconductor without inversion symmetry, both in the clean and disordered cases. The susceptibility has a large residual value at zero temperature, which is further enhanced in the presence of scalar impurities.Comment: 12 pages, 3 figure

    Holography and Unquenched Quark-Gluon Plasmas

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    We employ the string/gauge theory correspondence to study properties of strongly coupled quark-gluon plasmas in thermal gauge theories with a large number of colors and flavors. In particular, we analyze non-critical string duals of conformal (S)QCD, as well as ten dimensional wrapped fivebrane duals of SQCD-like theories. We study general properties of the dual plasmas, including the drag force exerted on a probe quark and the jet quenching parameter. We find that these plasma observables depend on the number of colors and flavors in the ``QCD dual''; in particular, we find that the jet quenching parameter increases linearly with N_f/N_c at leading order in the probe limit. In the ten dimensional case we find a non trivial drag coefficient but a vanishing jet quenching parameter. We comment on the relation of this result with total screening and argue that the same features are shared by all known plasmas dual to fivebranes in ten dimensions. We also construct new D5 black hole solutions with spherical horizon and show that they exhibit the same features.Comment: 30 pages. v2: Comments in section 2 and references updated, a typo fixe

    Spontaneous kidney rupture in polyarteritis nodosa presenting as an acute abdomen

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    CITATION: Edelstein, C. L. & Welke, H. 1991. Spontaneous kidney rupture in polyarteritis nodosa presenting as an acute abdome. South African Medical Journal, 79:52-53.The original publication is available at http://www.samj.org.zaAn acute abdomen in a patient with polyarteritis nodosa (PAN) is a perplexing and challenging problem for both the physician and the surgeon.Publisher’s versio

    Supersymmetric Electroweak Cosmic Strings

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    We study the connection between N=2N=2 supersymmetry and a topological bound in a two-Higgs-doublet system with an SU(2)×U(1)Y×U(1)YSU(2)\times U(1)_Y\times U(1)_{Y^{\prime}} gauge group. We derive the Bogomol'nyi equations from supersymmetry considerations showing that they hold provided certain conditions on the coupling constants, which are a consequence of the huge symmetry of the theory, are satisfied. Their solutions, which can be interpreted as electroweak cosmic strings breaking one half of the supersymmetries of the theory, are studied. Certain interesting limiting cases of our model which have recently been considered in the literature are finally analyzed.Comment: 20 pages, RevTe

    Magnetic properties of superconductors with strong spin-orbit coupling

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    We study the response of a superconductor with a strong spin-orbit coupling on an external magnetic field. The Ginzburg-Landau free energy functional is derived microscopically for a general crystal structure, both with and without an inversion center, and for an arbitrary symmetry of the superconducting order parameter. As a by-product, we obtain the general expressions for the intrinsic magnetic moment of the Cooper pairs. It is shown that the Ginzburg-Landau gradient energy in a superconductor lacking inversion symmetry has unusual structure. The general formalism is illustrated using as an example CePt3_3Si, which is the first known heavy-fermion superconductor without an inversion center.Comment: Published version, 14 pages, minor correction
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