62 research outputs found

    Some aspects of reconstruction using a scalar field in f (T ) Gravity

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    General relativity characterizes gravity as a geometric property exhibited on spacetime by massive objects while teleparallel gravity achieves the same results, at the level of equations, by taking a torsional perspective of gravity. Similar to f (R) theory, teleparallel gravity can also be generalized to f (T ), with the resulting field equations being inherently distinct from f (R) gravity in that they are second order, while in the former case they turn out to be fourth order. In the present case, a minimally coupled scalar field is investigated in the f (T ) gravity context for several forms of the scalar field potential. A number of new f (T ) solutions are found for these potentials, with their respective state parameters also being examined.Comment: 22 pages, 19 figures, to appear in EPJ

    Cosmological bouncing solutions in f(T,B) gravity

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    Teleparallel Gravity offers the possibility of reformulating gravity in terms of torsion by exchanging the Levi-Civita connection with the Weitzenb\"ock connection which describes torsion rather than curvature. Surprisingly, Teleparallel Gravity can be formulated to be equivalent to general relativity for a appropriate setup. Our interest lies in exploring an extension of this theory in which the Lagrangian takes the form of f(T,B)f(T,B) where T and B are two scalars that characterize the equivalency with general relativity. In this work, we explore the possible of reproducing well-known cosmological bouncing scenarios in the flat Friedmann-Lema\^itre-Robertson-Walker geometry using this approach to gravity. We study the types of gravitational Lagrangians which are capable of reconstructing analytical solutions for symmetric, oscillatory, superbounce, matter bounce, and singular bounce settings. These new cosmologically inspired models may have an effect on gravitational phenomena at other cosmological scales

    Modified Gravity Research

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    Five small articles by each author: 1 The Gravity Research Group by Jackson Levi Said 2 Cosmology and Gravity: The dark side of the universe by Gabriel Farrugia 3 Galactic Rotation Dynamics in Modifi ed Gravity by Andrew Finch 4 Exotic Stars by Mark Pacepeer-reviewe

    Cosmic Growth in f(T)f(T) Teleparallel Gravity

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    Physical evolution of cosmological models can be tested by using expansion data, while growth history of these models is capable of testing dynamics of the inhomogeneous parts of energy density. The growth factor, as well as its growth index, gives a clear indication of the performance of cosmological models in the regime of structure formation of early Universe. In this work, we explore the growth index in several leading f(T)f(T) cosmological models, based on a specific class of teleparallel gravity theories. These have become prominent in the literature and lead to other formulations of teleparallel gravity. Here we adopt a generalized approach by obtaining the M\'{e}sz\'{a}ros equation without immediately imposing the subhorizon limit, because this assumption could lead to over-simplification. This approach gives avenue to study at which kk modes the subhorizon limit starts to apply. We obtain numerical results for the growth factor and growth index for a variety of data set combinations for each f(T)f(T) model

    5-(1-Cyclo­hexen-1-yl)-3-(4-methoxy­phen­yl)isoxazole

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    In the title compound, C16H17NO2, the isoxazole ring makes a dihedral angle of 14.81 (13)° with the 4-methoxy­phenyl ring. Two atoms of the cyclo­hexene ring are disordered over two almost equally occupied positions [0.526 (13)/0.474 (13)]. The mol­ecular structure features a short intra­molecular C—H⋯O contact

    1-(3-Phenyl­isoxazol-5-yl)cyclo­hexane-1,2-diol

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    In the title compound, C15H17NO3, there are two mol­ecules in the asymmetric unit wherein the isoxazole rings make dihedral angles of 16.16 (15) and 16.79 (13)° with the benzene rings, and the cyclo­hexane rings adopt chair conformations. In both mol­ecules, the hydroxyl groups of the diol fragments are cis oriented, the O—C—C—O torsion angles being 60.76 (12) and −55.86 (11)°. The two mol­ecules are linked by a strong O—H⋯N hydrogen bond and the crystal packing is stabilized by one O—H⋯N and two O—H⋯O hydrogen bonds. An intra­molecular O—H⋯O hydrogen bond is observed in one of the mol­ecules
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