52,520 research outputs found

    Space-time Torsion and Neutrino Oscillations in Vacuum

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    The objective of this study is to verify the consistency of the prescription of alternative minimum coupling (connection) proposed by the Teleparallel Equivalent to General Relativity (TEGR) for the Dirac equation. With this aim, we studied the problem of neutrino oscillations in Weitzenbock space-time in the Schwarzschild metric. In particular, we calculate the phase dynamics of neutrinos. The relation of spin of the neutrino with the space-time torsion is clarified through the determination of the phase differences between spin eigenstates of the neutrinos.Comment: 07 pages, no figure

    Phase transitions in dependence of apex predator decaying ratio in a cyclic dominant system

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    Cyclic dominant systems, like rock-paper-scissors game, are frequently used to explain biodiversity in nature, where mobility, reproduction and intransitive competition are on stage to provide the coexistence of competitors. A significantly new situation emerges if we introduce an apex predator who can superior all members of the mentioned three-species system. In the latter case the evolution may terminate into three qualitatively different destinations depending on the apex predator decaying ratio qq. In particular, the whole population goes extinct or all four species survive or only the original three-species system remains alive as we vary the control parameter. These solutions are separated by a discontinuous and a continuous phase transitions at critical qq values. Our results highlight that cyclic dominant competition can offer a stable way to survive even in a predator-prey-like system that can be maintained for large interval of critical parameter values.Comment: version to appear in EPL. 7 pages, 7 figure

    Invasion controlled pattern formation in a generalized multi-species predator-prey system

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    Rock-scissors-paper game, as the simplest model of intransitive relation between competing agents, is a frequently quoted model to explain the stable diversity of competitors in the race of surviving. When increasing the number of competitors we may face a novel situation because beside the mentioned unidirectional predator-prey-like dominance a balanced or peer relation can emerge between some competitors. By utilizing this possibility in the present work we generalize a four-state predator-prey type model where we establish two groups of species labeled by even and odd numbers. In particular, we introduce different invasion probabilities between and within these groups, which results in a tunable intensity of bidirectional invasion among peer species. Our study reveals an exceptional richness of pattern formations where five quantitatively different phases are observed by varying solely the strength of the mentioned inner invasion. The related transition points can be identified with the help of appropriate order parameters based on the spatial autocorrelation decay, on the fraction of empty sites, and on the variance of the species density. Furthermore, the application of diverse, alliance-specific inner invasion rates for different groups may result in the extinction of the pair of species where this inner invasion is moderate. These observations highlight that beyond the well-known and intensively studied cyclic dominance there is an additional source of complexity of pattern formation that has not been explored earlier.Comment: 8 pages, 8 figures. To appear in PR

    Three dimensional Lifshitz black hole and the Korteweg-de Vries equation

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    We consider a solution of three dimensional New Massive Gravity with a negative cosmological constant and use the AdS/CTF correspondence to inquire about the equivalent two dimensional model at the boundary. We conclude that there should be a close relation with the Korteweg-de Vries equation.Comment: 4 page
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