192 research outputs found

    On the Bragg, Leibfried, and Modified Leibfried Numbers

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    The Bragg, Leibfried, and modified Leibfried numbers are defined in the context of a theory of dislocation-mediated melting, and their values are determined from the properties of the dislocation ensemble at the melting temperature. The approximate numerical coincidence of the Bragg and modified Leibfried numbers is explained. The parameter K in the definition of the modified Leibfried number is shown to be the natural logarithm of the effective coordination number. Our analysis reveals that the Bragg number can be considered an elemental constant, in contrast to the Leibfried and modified Leibfried numbers.Comment: 5 pages, LaTe

    Covariant Thermodynamics and ``Realistic'' Friedmann Model

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    We discuss a cosmological Friedmann model modified by inclusion of off-shell matter which has an equation of state p,ρT5,p,\rho \propto T^5, p=1/4ρ.p=1/4\rho . Such matter is shown to have energy density comparable with that of non-interacting radiation at temperatures of the order of the Hagedorn temperature, 1012\sim 10^{12} K, indicating the possibility of a phase transition. It is argued that the T5T^5-phase, or an admixture, lies below the high-temperature T4T^4-phase

    Galilean limit of equilibrium relativistic mass distribution for indistinguishable events

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    The relativistic distribution for indistinguishable events is considered in the mass-shell limit m2M2,m^2\cong M^2, where MM is a given intrinsic property of the events. The characteristic thermodynamic quantities are calculated and subject to the zero-mass and the high-temperature limits. The results are shown to be in agreement with the corresponding expressions of an on-mass-shell relativistic kinetic theory. The Galilean limit c,c\rightarrow \infty , which coincides in form with the low-temperature limit, is considered. The theory is shown to pass over to a nonrelativistic statistical mechanics of indistinguishable particles.Comment: Report TAUP-2136-9
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