3,524 research outputs found

    Indirect (source-free) integration method. II. Self-force consistent radial fall

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    We apply our method of indirect integration, described in Part I, at fourth order, to the radial fall affected by the self-force. The Mode-Sum regularisation is performed in the Regge-Wheeler gauge using the equivalence with the harmonic gauge for this orbit. We consider also the motion subjected to a self-consistent and iterative correction determined by the self-force through osculating stretches of geodesics. The convergence of the results confirms the validity of the integration method. This work complements and justifies the analysis and the results appeared in Int. J. Geom. Meth. Mod. Phys., 11, 1450090 (2014).Comment: To appear in Int. J. Geom. Meth. Mod. Phy

    Deep-inelastic Electron-Photon Scattering at High Q^2 : Neutral and Charged Current Reactions

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    We present the results of a calculation of deep inelastic electron-photon scattering at a linear collider for very high virtuality of the intermediate gauge boson up to NLO in perturbative QCD. The real photon is produced unpolarized via the Compton back scattering of laser light of the incoming beam. For Q2Q^2 values close to the masses squared of the Z and W gauge bosons, the deep inelastic electron-photon scattering process receives important contributions not only from virtual photon exchange but also from the exchange of a Z-boson and a W-boson. We find that the total cross section for center of mass energies above 500GeV500 \rm{GeV} is at least of O(pb){\cal O}(pb) and has an important charged current contribution.Comment: Talk given at the International Conference on the Structure and Interactions of the Photon, PHOTON 99, Freiburg im Breisgau, Germany, May 23-27, 1999. To be published in the Proceedings. 6 pages, 6 postscript figures. The complete paper, including figures, is also available via anonymous ftp at ftp://ttpux2.physik.uni-karlsruhe.de/ttp99/ttp99-30/ or via www at http://www-ttp.physik.uni-karlsruhe.de/Preprints

    Post-Operative Hemorrhage.

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    Measurement of Laser-Induced Thermo-Elastic Deformation In an Optic Using Polarization-Based Lateral Shearing Interferometry

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    polarization-based shearing interferometer is presented that is capable of measuring the thermal deformation of a mirror subject to heating from absorption of a Gaussian laser beam. The shear is generated by spatial walk-off in a birefringent crystal. By adjusting the orientation of the crystal, the components of the wavefront gradient can be independently measured to allow determination of the full wavefront vector gradate as well as reconstruction of the wavefront. Furthermore, the monolithic nature of the birefringent crystal allows non-critical alignment of the interferometer\u27s components. The interferogram is modulated, and a homodyne detection algorithm analyzes the modulated interferograms to extract the components of the wavefront gradient from which the wavefront is reconstructed. The thermal deformation of the laser-heated mirror was accurately observed with a sensitivity better than λ/160. The sensitivity of this interferometer is scale invariant, and we present a method to account for the non-uniform spatial frequency response of the interferometer

    Appendicitis; Protean Types.

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    Quantum transport of two-dimensional Dirac fermions in SrMnBi2

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    We report two-dimensional quantum transport in SrMnBi2_2 single crystals. The linear energy dispersion leads to the unusual nonsaturated linear magnetoresistance since all Dirac fermions occupy the lowest Landau level in the quantum limit. The transverse magnetoresistance exhibits a crossover at a critical field B∗B^* from semiclassical weak-field B2B^2 dependence to the high-field linear-field dependence. With increase in the temperature, the critical field B∗B^* increases and the temperature dependence of B∗B^* satisfies quadratic behavior which is attributed to the Landau level splitting of the linear energy dispersion. The effective magnetoresistant mobility μMR∼3400\mu_{MR}\sim 3400 cm2^2/Vs is derived. Angular dependent magnetoresistance and quantum oscillations suggest dominant two-dimensional (2D) Fermi surfaces. Our results illustrate the dominant 2D Dirac fermion states in SrMnBi2_2 and imply that bulk crystals with Bi square nets can be used to study low dimensional electronic transport commonly found in 2D materials like graphene.Comment: 5 papges, 4 figure

    A-STAR: The All-Sky Transient Astrophysics Reporter

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    The small mission A-STAR (All-Sky Transient Astrophysics Reporter) aims to locate the X-ray counterparts to ALIGO and other gravitational wave detector sources, to study the poorly-understood low luminosity gamma-ray bursts, and to find a wide variety of transient high-energy source types, A-STAR will survey the entire available sky twice per 24 hours. The payload consists of a coded mask instrument, Owl, operating in the novel low energy band 4-150 keV, and a sensitive wide-field focussing soft X-ray instrument, Lobster, working over 0.15-5 keV. A-STAR will trigger on ~100 GRBs/yr, rapidly distributing their locations.Comment: Accepted for the European Astronomical Society Publications Series: Proceedings of the Fall 2012 Gamma-Ray Burst Symposium held in Marbella, Spain, 8-12 Oct 201
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