4,160 research outputs found

    Mixed-symmetry massless gauge fields in AdS(5)

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    Free AdS(5) mixed-symmetry massless bosonic and fermionic gauge fields of arbitrary spins are described by using su(2,2) spinor language. Manifestly covariant action functionals are constructed and field equations are derived.Comment: 13 pages; v2: title changed, typos corrected, minor changes, reference added; v3: minor changes, published versio

    Tunable Integrated-Optics Nanoscaled Devices Based on Magnetic Photonic Crystals

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    Magnetooptical properties of magnetic photonic crystals have been investigated in the view of their possible applications for the modern integrated-optics devices. A "transfer matrices" formalism was expanded for the case of oblique light incidence on the periodic nanoscaled magnetic multilayered systems. Several new effects such as the Faraday effect dependence on the incidence angle and the tunability of the bandgap defect modes spectral location by external magnetic fields were found. Several possibilities of one-dimensional magnetic photonic crystals applications for the optical devices are discussed. Initial steps towards the practical implementation of the proposed devices are reported.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

    Higher Spin Gravitational Couplings and the Yang--Mills Detour Complex

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    Gravitational interactions of higher spin fields are generically plagued by inconsistencies. We present a simple framework that couples higher spins to a broad class of gravitational backgrounds (including Ricci flat and Einstein) consistently at the classical level. The model is the simplest example of a Yang--Mills detour complex, which recently has been applied in the mathematical setting of conformal geometry. An analysis of asymptotic scattering states about the trivial field theory vacuum in the simplest version of the theory yields a rich spectrum marred by negative norm excitations. The result is a theory of a physical massless graviton, scalar field, and massive vector along with a degenerate pair of zero norm photon excitations. Coherent states of the unstable sector of the model do have positive norms, but their evolution is no longer unitary and their amplitudes grow with time. The model is of considerable interest for braneworld scenarios and ghost condensation models, and invariant theory.Comment: 19 pages LaTe

    The steppe elephant Mammuthus trogontherii (Pohlig) from the Irtysh region near Omsk

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    A Pleistocene elephant skeleton was found in 1989 in the alluvial beds of the Tobolsk age on the Om River near the village of Ust’-Tarka (Ust’-Tarkskii District, Novosibirsk Region). The forelimbs and some thoracic and caudal vertebrae are not preserved. Judging from the heavy wear of M3/m3, this animal was about 50–60 years of individual age. The skeleton is about 3.5 m high at the withers. The geological age of the beds enclosing the skeleton and its morphological features suggest that it should be assigned to Mammuthus trogontherii
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