9,042 research outputs found

    The U(1)A anomaly in noncommutative SU(N) theories

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    We work out the one-loop U(1)AU(1)_A anomaly for noncommutative SU(N) gauge theories up to second order in the noncommutative parameter θμν\theta^{\mu\nu}. We set θ0i=0\theta^{0i}=0 and conclude that there is no breaking of the classical U(1)AU(1)_A symmetry of the theory coming from the contributions that are either linear or quadratic in θμν\theta^{\mu\nu}. Of course, the ordinary anomalous contributions will be still with us. We also show that the one-loop conservation of the nonsinglet currents holds at least up to second order in θμν\theta^{\mu\nu}. We adapt our results to noncommutative gauge theories with SO(N) and U(1) gauge groups.Comment: 50 pages, 5 figures in eps files. Some comments and references adde

    Comparing hierarchies of total functionals

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    In this paper we consider two hierarchies of hereditarily total and continuous functionals over the reals based on one extensional and one intensional representation of real numbers, and we discuss under which asumptions these hierarchies coincide. This coincidense problem is equivalent to a statement about the topology of the Kleene-Kreisel continuous functionals. As a tool of independent interest, we show that the Kleene-Kreisel functionals may be embedded into both these hierarchies.Comment: 28 page

    Memory effect in triglycine sulfate induced by a transverse electric field: specific heat measurement

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    The influence of a transverse electric field in the specific heat of triglycine sulphate (TGS) has been studied. The specific heat of TGS has been measured heating the sample from ferroelectric to paraelectric phase after prolonged transverse electric field (i.e. perpendicular to the ferroelectric axis). It is shown that the specific heat of TGS can remember the temperature TsT_s at which the transverse field was previously applied.Comment: ReVTeX4 Twocolumn 4 pages, 4 figure

    Generalized scattering-matrix approach for magneto-optics in periodically patterned multilayer systems

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    We present here a generalization of the scattering-matrix approach for the description of the propagation of electromagnetic waves in nanostructured magneto-optical systems. Our formalism allows us to describe all the key magneto-optical effects in any configuration in periodically patterned multilayer structures. The method can also be applied to describe periodic multilayer systems comprising materials with any type of optical anisotropy. We illustrate the method with the analysis of a recent experiment in which the transverse magneto-optical Kerr effect was measured in a Fe film with a periodic array of subwavelength circular holes. We show, in agreement with the experiments, that the excitation of surface plasmon polaritons in this system leads to a resonant enhancement of the transverse magneto-optical Kerr effect.Comment: 12 pages, 6 figures, submitted to Physical Review

    Universal Conductance Distributions in the Crossover between Diffusive and Localization Regimes

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    The full distribution of the conductance P(G)P(G) in quasi-one-dimensional wires with rough surfaces is analyzed from the diffusive to the localization regime. In the crossover region, where the statistics is dominated by only one or two eigenchannels, the numerically obtained P(G) is found to be independent of the details of the system with the average conductance as the only scaling parameter. For < e^2/h, P(G) is given by an essentially ``one-sided'' log-normal distribution. In contrast, for e^2/h <= 2e^2/h, the shape of P(G) remarkable agrees with those predicted by random matrix theory for two fluctuating transmission eigenchannels.Comment: Accepted for publication in Phys. Rev. Let

    Notas nomenclaturales sobre anfibios actuales y fĂłsiles

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    A review of extinct and living amphibians known from fossils (Allocaudata, Anura and Caudata) has revealed several cases that require nomenclatural changes in order to stabilize the taxonomy of the group. Nomenclatural changes include homonym replacements, corrections of spelling variants and authorships, name availabilities, and in particular, the proposal of new combinations. These changes will allow the incorporation of some palaeontological taxa to the current evolutionary models of relationship of modern forms based on molecular phylogenies. Rana cadurcorum for Rana plicata Filhol, 1877, Rana auscitana for Rana pygmaea Lartet, 1851, and Rana sendoa for Rana robusta Brunner, 1956. Anchylorana Taylor, 1942 is considered a new synonym of Lithobates Fitzinger, 1843. New combinations proposed are: Anaxyrus defensor for Bufo defensor Meylan, 2005; Anaxyrus hibbardi for Bufo hibbardi Taylor, 1937; Anaxyrus pliocompactilis for Bufo pliocompactilis Wilson, 1968; Anaxyrus repentinus for Bufo repentinus Tihen, 1962; Anaxyrus rexroadensis for Bufo rexroadensis Tihen, 1962; Anaxyrus spongifrons for Bufo spongifrons Tihen, 1962; Anaxyrus suspectus for Bufo suspectus Tihen, 1962; Anaxyrus tiheni for Bufo tiheni Auffenberg, 1957; Anaxyrus valentinensis for Bufo valentinensis Estes et Tihen, 1964; Ichthyosaura wintershofi for Triturus wintershofi Lunau, 1950; Incilius praevius for Bufo praevius Tihen, 1951; Lithobates bucella for Rana bucella Holman, 1965; Lithobates dubitus for Anchylorana dubita Taylor, 1942; Lithobates fayeae for Rana fayeae Taylor, 1942; Lithobates miocenicus for Rana miocenica Holman, 1965; Lithobates moorei for Anchylorana moorei Taylor, 1942; Lithobates parvissimus for Rana parvissima Taylor, 1942; Lithobates rexroadensis for Rana rexroadensis Taylor, 1942; Lithobates robustocondylus for Anchylorana robustocondyla Taylor, 1942; Ommatotriton roehrsi for Triturus roehrsi Herre, 1955; Pelophylax barani for Rana barani Rückert-Ülkumen, 1980; Pelophylax meriani for Rana meriani Meyer, 1853; Pelophylax pueyoi for Rana pueyoi Navás, 1922a; Pelophylax quellenbergi for Rana quellenbergi Navás, 1922; Philoria borealis for Kyarranus borealis Tyler, 1991; Pseudepidalea belogorica for Bufo belogoricus Ratnikov, 1993; Pseudepidalea plana for Bufo planus Ratnikov, 1993; Pseudepidalea prisca for Bufo priscus Spinar, Klembara et Meszáros, 1993, and Pseudepidalea stranensis for Bufo stranensis Nemec, 1972. The names Geyeriellinae Brame, 1958, Palaeurodelidae Brame, 1958, Prosalamandridae Stefano, 1903, Lipelucidae Huene, 1956, Rana temporaria fossilis Stefanov, 1951, Salteniidae Kuhn, 1962, Vieraellidae Reig, 1961, and Voigtiellinae Brame, 1958 are nomenclaturally deemed unavailable. The family name based on Scapherpeton Cope, 1876 is Scapherpetidae and not Scapherpetonidae nor Scapherpetontidae.Una revisión de anfibios extintos y actuales en estado fósil (Allocaudata, Anura y Caudata) ha permitido detectar diversos casos que precisan cambios nomenclaturales a fin de estabilizar la taxonomía del grupo. Los cambios nomenclaturales incluyen homonimias, correcciones de variantes gramaticales y autorías, disponibilidad de nombres, y en especial la propuesta de nuevas combinaciones, necesarias para ajustar algunos taxones paleontológicos a los modelos de relaciones evolutivas entre formas vivientes, fundamentados en filogenias moleculares. Las nuevas combinaciones que se proponen son: Anaxyrus defensor para Bufo defensor Meylan, 2005; Anaxyrus hibbardi para Bufo hibbardi Taylor, 1937; Anaxyrus pliocompactilis para Bufo pliocompactilis Wilson, 1968; Anaxyrus repentinus para Bufo repentinus Tihen, 1962; Anaxyrus rexroadensis para Bufo rexroadensis Tihen, 1962; Anaxyrus spongifrons para Bufo spongifrons Tihen, 1962; Anaxyrus suspectus para Bufo suspectus Tihen, 1962; Anaxyrus tiheni para Bufo tiheni Auffenberg, 1957; Anaxyrus valentinensis para Bufo valentinensis Estes et Tihen, 1964; Ichthyosaura wintershofi para Triturus wintershofi Lunau, 1950; Incilius praevius para Bufo praevius Tihen, 1951; Lithobates bucella para Rana bucella Holman, 1965; Lithobates dubitus para Anchylorana dubita Taylor, 1942; Lithobates fayeae para Rana fayeae Taylor, 1942; Lithobates miocenicus para Rana miocenica Holman, 1965; Lithobates moorei para Anchylorana moorei Taylor, 1942; Lithobates parvissimus para Rana parvissima Taylor, 1942; Lithobates rexroadensis para Rana rexroadensis Taylor, 1942; Lithobates robustocondylus para Anchylorana robustocondyla Taylor, 1942; Ommatotriton roehrsi para Triturus roehrsi Herre, 1955; Pelophylax barani para Rana barani Rückert-Ülkumen, 1980; Pelophylax meriani para Rana meriani Meyer, 1853; Pelophylax pueyoi para Rana pueyoi Navás, 1922a; Pelophylax quellenbergi para Rana quellenbergi Navás, 1922; Philoria borealis para Kyarranus borealis Tyler, 1991; Pseudepidalea belogorica para Bufo belogoricus Ratnikov, 1993; Pseudepidalea plana para Bufo planus Ratnikov, 1993; Pseudepidalea prisca para Bufo priscus Spinar, Klembara et Meszáros, 1993, y Pseudepidalea stranensis para Bufo stranensis Nemec, 1972. Los nombres Geyeriellinae Brame, 1958, Palaeurodelidae Brame, 1958, Prosalamandridae Stefano, 1903, Lipelucidae Huene, 1956, Rana temporaria fossilis Stefanov, 1951, Salteniidae Kuhn, 1962, Vieraellidae Reig, 1961, y Voigtiellinae Brame, 1958 se consideran nomenclaturalmente no disponibles. El nombre de familia basado en Scapherpeton Cope, 1876 es Scapherpetidae y no Scapherpetonidae ni Scapherpetontidae

    Influence of the magnetic field on the plasmonic properties of transparent Ni anti-dot arrays

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    Extraordinary optical transmission is observed due to the excitation of surface plasmon polaritons (SPPs) in 2-Dimensional hexagonal anti-dot patterns of pure Ni thin films, grown on sapphire substrates. A strong enhancement of the polar Kerr rotation is recorded at the surface plasmon related transmission maximum. Angular resolved reflectivity measurements under an applied field, reveal an enhancement and a shift of the normalized reflectivity difference upon reversal of the magnetic saturation (transverse magneto-optical Kerr effect-TMOKE). The change of the TMOKE signal clearly shows the magnetic field modulation of the dispersion relation of SPPs launched in a 2D patterned ferromagnetic Ni film
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