2,915 research outputs found
Tsallis and Kaniadakis statistics from a point of view of the holographic equipartition law
In this work, we have illustrated the difference between both Tsallis and
Kaniadakis entropies through cosmological models obtained from the formalism
proposed by Padmanabhan, which is called holographic equipartition law.
Similarly to the formalism proposed by Komatsu, we have obtained an extra
driving constant term in the Friedmann equation if we deform the Tsallis
entropy by Kaniadakis' formalism. We have considered initially Tsallis entropy
as the Black Hole (BH) area entropy. This constant term may lead the universe
to be in an accelerated mode. On the other hand, if we start with the
Kaniadakis entropy as the BH area entropy and then by modifying the Kappa
expression by Tsallis' formalism, the same constant, which shows that the
universe have an acceleration is obtained. In an opposite limit, no driving
inflation term of the early universe was derived from both deformations.Comment: 8 pages, preprint format. Final version to appear in Europhysics
Letter
Upper limits to absorption enhancement in thick solar cells using diffraction gratings
The application of diffraction gratings to solar cells is a promising approach to superseding the light trapping limits of conventional Lambertian structures. In this paper a mathematical formalism is derived for calculating the absorption that can be expected in a solar cell equipped with a diffraction grating, which can be applied to any lattice geometry and grating profile. Furthermore, the formalism is used to calculate the upper limit of total absorption that can theoretically be achieved using a diffraction grating. The derived formalism and limits are valid when the solar cell thickness is greater than the coherence length of the illuminating solar spectrum. Comparison is made to the upper limit achievable using an angularly selective Rugate filter, which is also calculated. Both limits are found to be considerably higher than the Lambertian limit within the range of sunlight concentration factors practically employed in photovoltaic systems (1–1000×). The upper limit of absorption using the diffraction grating is shown to be equal to the thermodynamic limit for all absorbances and concentration factors. The limit for the Rugate filter is generally lower, but tends to the thermodynamic limit for lower cell absorbance
Tsallis' entropy, modified Newtonian accelerations and the Tully-Fisher relation
In this paper we have shown that the connection between the number of bits
and the area of the holographic screen, where both were established in
Verlinde's theory of entropic gravity, may depend on the thermostatistics
theory previously chosen. Starting from the Boltzmann-Gibbs (BG) theory, we
have reobtained the usual dependency of both, bits number and area. After that,
using Tsallis' entropy concept within the entropic gravity formalism, we have
derived another relation between the bits number and the holographic screen
area. Moreover, we have used this new relation to derive three Newtonian-type
accelerations in the context of Tsallis' statistics. Moreover, we have used
this new relation to derive three Newtonian-type acceleration in the context of
Tsallis statistics which are a modified gravitational acceleration, a modified
MOND theory and a modified Friedmann equation. We have obtained the
nonextensive version of the Tully-Fisher (TF) relation which shows a dependency
of the distance of the star in contrast to the standard TF expression. The BG
limit gives the standard TF law.Comment: 12 pages. Preprint forma
Finite group actions on reductive groups and buildings and tamely-ramified descent in Bruhat-Tits theory
The purpose of the paper is to give a new approach to tamely-ramified descent
in Bruhat-Tits theory. This descent was first studied by Guy Rousseau in his
thesis.Comment: 28 pages. arXiv admin note: text overlap with arXiv:1611.0743
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