Browsing by Author "Orozco Araujo, Vicmar Carolina"

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    Gravedad Tenso-Escalar a Partir de Simetrías de Poincaré Generalizadas.
    (Universidad de Concepción, 2023) Orozco Araujo, Vicmar Carolina; Salgado Arias, Patricio
    The Randall-Sundrum (RS) compactification procedure was studied as well as its implications in the cosmological solutions in the context of Chern-Simons (ChS) gravity and Einstein-Gauss-Bonnet (EGB) gravity. The first part of this thesis consists of using the mentioned compactification procedure on the 5D AdSL4- ChS gravity action, from which an extended four-dimensional Einstein-Hilbert (EH) action with cosmological term, including non-Abelian ˜k mn µ gauge fields, was obtained. The same compactification procedure was used in the action describing ChS gravity for the Maxwell algebra in 5D, from which a 4D extended Einstein gravity with cosmological term and Abelian gauge fields coinciding with equation (29) of (16) was obtained. Employing the Inönü-Wigner contraction procedure on the compactified action gotten from AdSL4-ChS gravity in 5D was found in equation (29) of (16). We point out that the ˜k mn µ gauge fields can be interpreted as possible geometric vector fields of the inflaton. In the second part of the thesis, the Lagrangian of the action for EGB in 5D was considered, from which the field equations for the Friedmann-Lemaître-Robertson-Walker metric together with some solutions were obtained. The RS compactification procedure was used on the 5D EGB gravity, which resulted in the 4D Einstein-Hilbert (EH) gravity action with cosmological constant. This result allowed us to write the cosmological constant Λ4D in terms of the pair (rc,Λ5D), from which we speculate that Λ4D has its origin in the compactification radius rc and in the cosmological constant of the fifth dimension Λ5D. Applying the RS compactification on AdS-ChS gravity was found EH gravity with cosmological constant in 4D, from which was obtained Λ4D in terms of rc, leading to the interpretation of the parameter l as the size of the universe. Finally, we employed the RS compactification on EChS gravity in 5D, which led us to an action for a scalar-tensor gravity in 4D that includes a GB term, this action corresponds to a particular case of Horndeski theory, namely the Lagrangian (48) of (24).
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