4,519 research outputs found

    Light speed variation from gamma ray bursts: criteria for low energy photons

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    We examine a method to detect the light speed variation from gamma ray burst data observed by the Fermi Gamma-ray Space Telescope (FGST). We suggest new criteria to determine the characteristic time for low energy photons by the energy curve and the average energy curve, and obtain similar results compared with those from the light curve. We offer a new criterion with both the light curve and the average energy curve to determine the characteristic time for low energy photons. We then apply the new criteria to the GBM NaI data, the GBM BGO data, and the LAT LLE data, and obtain consistent results for three different sets of low energy photons from different FERMI detectors.Comment: 26 latex pages, 23 figures, final version for publicatio

    Z_3 Symmetry and Neutrino Mixing in Type II Seesaw

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    Neutrino mixing matrix satisfying the current experimental data can be well described by the HPS tri-bimaximal mixing matrix. We propose that its origin can be understood within the seesaw framework by a hidden condition on the mass matrix of heavy right-handed neutrinos under the transformation of the Abelian finite group Z_3 on the flavor basis. Ignoring CP phases, we show that it can lead to the generic form of the effective light neutrino mass matrix from which the HPS mixing matrix appears naturally, as well as an expeimentally allowed non-zero \sin\theta_{13}. We show that the model based on our proposal is in good agreement with the current experimental data.Comment: 9 page

    Composition portfolio

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    This portfolio of original compositions includes two acoustic works and four electroacoustic works. Surrounded in the dark is a trio for clarinet, violin and violoncello in two movements. It explores a variety of emotional experiences in a world full of darkness. You zi yin is an electroacoustic piece that combines acoustic and electroacoustic techniques to portray the relationship between a mother and her son. The electroacoustic work Small change explores relationships people have with hard currency and the emotions it evokes. Samsara is an orchestral work in three movements that explores the idea of a never-ending cycle of birth, death and rebirth. After dusk is a dramatic electroacoustic work that is composed of samples from a woodblock and a violin. The work was inspired by the poem ‘Fire and Ice’ by Robert Frost. The sound track to A tick is the last work in this portfolio, it is based on a movie of traditional Chinese shadow puppetry that describes a story about two frogs, a crane and a turtle

    Lifshitz Scaling Effects on Holographic Superconductors

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    Via numerical and analytical methods, the effects of the Lifshitz dynamical exponent zz on holographic superconductors are studied in some detail, including ss wave and pp wave models. Working in the probe limit, we find that the behaviors of holographic models indeed depend on concrete value of zz. We obtain the condensation and conductivity in both Lifshitz black hole and soliton backgrounds with general zz. For both ss wave and pp wave models in the black hole backgrounds, as zz increases, the phase transition becomes more difficult and the growth of conductivity is suppressed. For the Lifshitz soliton backgrounds, when zz increases (z=1, 2, 3z=1,~2,~3), the critical chemical potential decreases in the ss wave cases but increases in the pp wave cases. For pp wave models in both Lifshitz black hole and soliton backgrounds, the anisotropy between the AC conductivity in different spatial directions is suppressed when zz increases. The analytical results uphold the numerical results.Comment: Typos corrected; Footnote added; References added; To be published in Nuclear Physics
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