917 research outputs found

    Cosmological model with local symmetry of very special relativity and constraints on it from supernovae

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    Based on Cohen \& Glashow's very special relativity [A. G. Cohen and S. L. Glashow, Phys. Rev. Lett. {\bf 97} (2006) 021601], we propose an anisotropic modification to the Friedmann-Robertson-Walker (FRW) line element. An arbitrarily oriented 1-form is introduced and the FRW spacetime becomes of the Randers-Finsler type. The 1-form picks out a privileged axis in the universe. Thus, the cosmological redshift as well as the Hubble diagram of the type Ia supernovae (SNe Ia) becomes anisotropic. By directly analyzing the Union2 compilation, we obtain the privileged axis pointing to (l,b)=(304∘±43∘,−27∘±13∘)(l,b)=({304^\circ}\pm{43^\circ},{-27^\circ}\pm{13^\circ}) (68% C.L.68\%~\rm{C.L.}). This privileged axis is close to those obtained by comparing the best-fit Hubble diagrams in pairs of hemispheres. It should be noticed that the result is consistent with isotropy at the 1σ1\sigma level since the anisotropic magnitude is D=0.03±0.03D=0.03\pm 0.03.Comment: 13 pages, 2 figures. Published at EPJC(2013

    Finslerian MOND versus the Strong Gravitational Lensing of the Early-type Galaxies

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    The gravitational lensing of Bullet Clusters and early-type galaxies pose serious challenges on the validity of MOND. Recently, Finslerian MOND, a generalization of MOND in the framework of Finsler gravity, has been proposed to explain the mass discrepancy problem of Bullet Cluster 1E 0657\ 558. In this paper, we check the validity of the Finslerian MOND in describing the strong gravitational lensing of early-type galaxies. The investigation on ten strong lenses of the CASTLES samples shows that there is no strong evidence for the existence of dark matter.Comment: 11 pages, 2 figures, 2 table

    Ballistic Thermal Rectification in Asymmetric Three-Terminal Mesoscopic Dielectric Systems

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    By coupling the asymmetric three-terminal mesoscopic dielectric system with a temperature probe, at low temperature, the ballistic heat flux flow through the other two asymmetric terminals in the nonlinear response regime is studied based on the Landauer formulation of transport theory. The thermal rectification is attained at the quantum regime. It is a purely quantum effect and is determined by the dependence of the ratio τRC(ω)/τRL(ω)\tau_{RC}(\omega)/\tau_{RL}(\omega) on ω\omega, the phonon's frequency. Where τRC(ω)\tau_{RC}(\omega) and τRL(ω)\tau_{RL}(\omega) are respectively the transmission coefficients from two asymmetric terminals to the temperature probe, which are determined by the inelastic scattering of ballistic phonons in the temperature probe. Our results are confirmed by extensive numerical simulations.Comment: 10 pages, 4 figure
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