2,413 research outputs found

    Mixed Symmetry Solutions of Generalized Three-Particle Bargmann-Wigner Equations in the Strong-Coupling Limit

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    Starting from a nonlinear isospinor-spinor field equation, generalized three-particle Bargmann-Wigner equations are derived. In the strong-coupling limit, a special class of spin 1/2 bound-states are calculated. These solutions which are antisymmetric with respect to all indices, have mixed symmetries in isospin-superspin space and in spin orbit space. As a consequence of this mixed symmetry, we get three solution manifolds. In appendix \ref{b}, table 2, these solution manifolds are interpreted as the three generations of leptons and quarks. This interpretation will be justified in a forthcoming paper.Comment: 17 page

    On a Classical, Geometric Origin of Magnetic Moments, Spin-Angular Momentum and the Dirac Gyromagnetic Ratio

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    By treating the real Maxwell Field and real linearized Einstein equations as being imbedded in complex Minkowski space, one can interpret magnetic moments and spin-angular momentum as arising from a charge and mass monopole source moving along a complex world line in the complex Minkowski space. In the circumstances where the complex center of mass world-line coincides with the complex center of charge world-line, the gyromagnetic ratio is that of the Dirac electron.Comment: 17 page

    Boundary critical behaviour at mm-axial Lifshitz points: the special transition for the case of a surface plane parallel to the modulation axes

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    The critical behaviour of dd-dimensional semi-infinite systems with nn-component order parameter ϕ\bm{\phi} is studied at an mm-axial bulk Lifshitz point whose wave-vector instability is isotropic in an mm-dimensional subspace of Rd\mathbb{R}^d. Field-theoretic renormalization group methods are utilised to examine the special surface transition in the case where the mm potential modulation axes, with 0md10\leq m\leq d-1, are parallel to the surface. The resulting scaling laws for the surface critical indices are given. The surface critical exponent ηsp\eta_\|^{\rm sp}, the surface crossover exponent Φ\Phi and related ones are determined to first order in \epsilon=4+\case{m}{2}-d. Unlike the bulk critical exponents and the surface critical exponents of the ordinary transition, Φ\Phi is mm-dependent already at first order in ϵ\epsilon. The \Or(\epsilon) term of ηsp\eta_\|^{\rm sp} is found to vanish, which implies that the difference of β1sp\beta_1^{\rm sp} and the bulk exponent β\beta is of order ϵ2\epsilon^2.Comment: 21 pages, one figure included as eps file, uses IOP style file

    Nonlocal restoration of two-mode squeezing in the presence of strong optical loss

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    We present the experimental realization of a theoretical effect discovered by Olivares and Paris, in which a pair of entangled optical beams undergoing independent losses can see nonlocal correlations restored by the use of a nonlocal resource correlating the losses. Twin optical beams created in an entangled Einstein-Podolsky-Rosen (EPR) state by an optical parametric oscillator above threshold were subjected to 50% loss from beamsplitters in their paths. The resulting severe degradation of the signature quantum correlations observed between the two beams was then suppressed when another, independent EPR state impinged upon the other input ports of the beamsplitters, effectively entangling the losses inflicted to the initial EPR state. The additional EPR beam pair was classically coherent with the primary one but had no quantum correlations with it. This result may find applications as a quantum tap for entanglement.Comment: 14 pages, 6 figures, submitted for publicatio

    Centrifugal force induced by relativistically rotating spheroids and cylinders

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    Starting from the gravitational potential of a Newtonian spheroidal shell we discuss electrically charged rotating prolate spheroidal shells in the Maxwell theory. In particular we consider two confocal charged shells which rotate oppositely in such a way that there is no magnetic field outside the outer shell. In the Einstein theory we solve the Ernst equations in the region where the long prolate spheroids are almost cylindrical; in equatorial regions the exact Lewis "rotating cylindrical" solution is so derived by a limiting procedure from a spatially bound system. In the second part we analyze two cylindrical shells rotating in opposite directions in such a way that the static Levi-Civita metric is produced outside and no angular momentum flux escapes to infinity. The rotation of the local inertial frames in flat space inside the inner cylinder is thus exhibited without any approximation or interpretational difficulties within this model. A test particle within the inner cylinder kept at rest with respect to axes that do not rotate as seen from infinity experiences a centrifugal force. Although the spacetime there is Minkowskian out to the inner cylinder nevertheless that space has been induced to rotate, so relative to the local inertial frame the particle is traversing a circular orbit.Comment: 12 pages, 2 figure

    Lack of IL‐6 augments inflammatory response but decreases vascular permeability in bacterial meningitis

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    Interleukin (IL)‐6 is a multifunctional cytokine with diverse actions and has been implicated in the pathophysiology of many neurological and inflammatory disorders. In this study, we investigated the role of IL‐6 in pneumococcal meningitis. Cerebral infection in wild‐type (WT) mice caused an increase in vascular permeability and intracranial pressure (ICP), which were significantly reduced in IL‐6-/- mice. In contrast, meningitis in IL‐6-/- mice was associated with a significant increase in CSF white blood cell count compared with infected WT mice, indicating an enhanced inflammatory response. Analysis of mRNA expression in the brain showed an increase in tumour necrosis factor (TNF)‐α, IL‐1β, and macrophage inflammatory protein 2 (MIP‐2) levels, but decreased expression of granulocyte-macrophage colony‐stimulating factor in infected IL‐6-/- mice compared with infected WT controls. Similar results were obtained when rats challenged with pneumococci were systemically treated with neutralizing anti‐IL‐6 antibodies, resulting in an increased pleocytosis but at the same time a reduction of vascular permeability, brain oedema formation, and ICP, which was not accompanied by a downregulation of matrix metalloproteinases. Our data indicate that IL‐6 plays an important anti‐inflammatory role in bacterial meningitis by reducing leukocyte infiltration but contributes to the rise in intracranial pressure by increasing blood-brain barrier (BBB) permeability. These findings suggest that the migration of leukocytes across the BBB and the increase in vascular permeability are two independent processes during bacterial meningiti
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