Browsing by Author "Olea, R"

Now showing 1 - 7 of 7
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    Charged rotating black hole formation from thin shell collapse in three dimensions
    (2005) Olea, R
    The thin shell collapse leading to the formation of charged rotating black holes in three dimensions is analyzed in the light of a recently developed Hamiltonian formalism for these systems. It is proposed to demand, as a way to reconcile the properties of an infinitely extended solenoid in flat space with a magnetic black hole in three dimensions, that the magnetic field should vanish just outside the shell. The adoption of this boundary condition results in an exterior solution with a magnetic field different from zero at a finite distance from the shell. The interior solution is also found and assigns another interpretation, in a different context, to the magnetic solution previously obtained by Clement and Hirschmann and Welch.
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    Counterterms and dual holographic anomalies in CS gravity -: art. no. 067
    (2005) Bañados, M; Olea, R; Theisen, S
    The holographic Weyl anomaly associated to Chern-Simons gravity in 2n + 1 dimensions is proportional to the Euler term in 2n dimensions, with no contributions from the Weyl tensor. We compute the holographic energy-momentum tensor associated to Chern-Simons gravity directly from the action, in an arbitrary odd-dimensional spacetime. We show, in particular, that the counterterms rendering the action finite contain only terms of the Lovelock type.
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    Finite action principle for Chern-Simons AdS gravity
    (2004) Mora, P; Olea, R; Troncoso, R; Zanelli, J
    A finite action principle for Chern-Simons AdS gravity is presented. The construction is carried out in detail first in five dimensions, where the bulk action is given by a particular combination of the Einstein-Hilbert action with negative cosmological constant and a Gauss-Bonnet term; and is then generalized for arbitrary odd dimensions. The boundary term needed to render the action finite is singled out demanding the action to attain an extremum for an appropriate set of boundary conditions. The boundary term is a local function of the fields at the boundary and is sufficient to render the action finite for asymptotically AdS solutions, without requiring background fields. It is shown that the Euclidean continuation of the action correctly describes black hole thermodynamics in the canonical ensemble. Additionally, background independent conserved charges associated with the asymptotic symmetries can be written as surface integrals by direct application of Noether's theorem.
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    Hamiltonian treatment of the gravitational collapse of thin shells -: art. no. 104023
    (2004) Crisóstomo, J; Olea, R
    A Hamiltonian treatment of the gravitational collapse of thin shells is presented. The direct integration of the canonical constraints reproduces the standard shell dynamics for a number of known cases. The formalism is applied in detail to three-dimensional spacetime and the properties of the (2+1)-dimensional charged black hole collapse are further elucidated. The procedure is also extended to deal with rotating solutions in three dimensions. The general form of the equations providing the shell dynamics implies the stability of black holes, as they cannot be converted into naked singularities by any shell collapse process.
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    Mass, angular momentum and thermodynamics in four-dimensional Kerr-AdS black holes
    (2005) Olea, R
    In this paper, the connection between the Lorentz- covariant counterterms that regularize the four-dimensional AdS gravity action and topological invariants is explored. It is shown that demanding the spacetime to have a negative constant curvature in the asymptotic region permits the explicit construction of such series of boundary terms. The orthonormal frame is adapted to appropriately describe the boundary geometry and, as a result, the boundary term can be expressed as a functional of the boundary metric, extrinsic curvature and intrinsic curvature. This choice also allows to write down the background-independent Noether charges associated to asymptotic symmetries in standard tensorial formalism.
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    Supersymmetric extension of the nine-dimensional continuation of the Euler density with N=2
    (2004) Hassaïne, M; Olea, R; Troncoso, R
    A local supersymmetric extension with N = 2 of the dimensional continuation of the Euler-Gauss-Bonnet density from eight to nine dimensions is constructed. The gravitational sector is invariant under local Poincare translations, and the full field content is given by the vielbein, the spin connection, a complex gravitino, and an Abelian one-form. The local symmetry group is shown to be super Poincare with N = 2 and a U(l) central extension, and the full supersymmetric Lagrangian can be written as a Chem-Simons form. (C) 2004 Published by Elsevier B.V.
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    Transgression forms and extensions of Chern-Simons gauge theories
    (2006) Mora, P; Olea, R; Troncoso, R; Zanelli, J
    A gauge invariant action principle, based on the idea of transgression forms, is proposed. The action extends the Chern-Simons form by the addition of a boundary term that makes the action gauge invariant (and not just quasi-invariant). Interpreting the spacetime manifold as cobordant to another one, the duplication of gauge fields in spacetime is avoided. The advantages of this approach are particularly noticeable for the gravitation theory described by a Chern-Simons lagrangian for the AdS group, in which case the action is regularized and finite for black hole geometries in diverse situations. Black hole thermodynamics is correctly reproduced using either a background field approach or a background-independent setting, even in cases with asymptotically nontrivial topologies. It is shown that the energy found from the thermodynamic analysis agrees with the surface integral obtained by direct application of Noether's theorem.