11,040 research outputs found

    Inertial-Hall effect: the influence of rotation on the Hall conductivity

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    Inertial effects play an important role in classical mechanics but have been largely overlooked in quantum mechanics. Nevertheless, the analogy between inertial forces on mass particles and electromagnetic forces on charged particles is not new. In this paper, we consider a rotating non-interacting planar two-dimensional electron gas with a perpendicular uniform magnetic field and investigate the effects of the rotation in the Hall conductiv

    Quantitative Kinetic Energy Estimated from Disdrometer Signal

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    The kinetic energy of the rain drops was predicted in a relation between the rain rate and rain quantity, derived directly from the rain drop size distribution (DSD), which had been measured by a disdrometer located in the eastern state of Alagoas-Brazil. The equation in the form of exponential form suppressed the effects of large drops at low rainfall intensity observed at the beginning and end of the rainfall. The kinetic energy of the raindrop was underestimated in almost rain intensity ranges and was considered acceptable by the performance indicators such as coefficient of determination, average absolute error, percent relative error, mean absolute error, root mean square error, Willmott's concordance index and confidence index

    Semiclassical back reaction around a cosmic dislocation

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    The energy-momentum vacuum average of a conformally coupled massless scalar field vibrating around a cosmic dislocation (a cosmic string with a dislocation along its axis) is taken as source of the linearized semiclassical Einstein equations. The solution up to first order in the Planck constant is derived. Motion of a test particle is then discussed, showing that under certain circumstances a helical-like dragging effect, with no classical analogue around the cosmic dislocation, is induced by back reaction.Comment: Published version, 4 pages, no figures, REVTeX4 fil

    Stellar equilibrium configurations of white dwarfs in the f(R,T)f(R,T) gravity

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    In this work we investigate the equilibrium configurations of white dwarfs in a modified gravity theory, na\-mely, f(R,T)f(R,T) gravity, for which RR and TT stand for the Ricci scalar and trace of the energy-momentum tensor, respectively. Considering the functional form f(R,T)=R+2λTf(R,T)=R+2\lambda T, with λ\lambda being a constant, we obtain the hydrostatic equilibrium equation for the theory. Some physical properties of white dwarfs, such as: mass, radius, pressure and energy density, as well as their dependence on the parameter λ\lambda are derived. More massive and larger white dwarfs are found for negative values of λ\lambda when it decreases. The equilibrium configurations predict a maximum mass limit for white dwarfs slightly above the Chandrasekhar limit, with larger radii and lower central densities when compared to standard gravity outcomes. The most important effect of f(R,T)f(R,T) theory for massive white dwarfs is the increase of the radius in comparison with GR and also f(R)f(R) results. By comparing our results with some observational data of massive white dwarfs we also find a lower limit for λ\lambda, namely, λ>3×104\lambda >- 3\times 10^{-4}.Comment: To be published in EPJ
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