Research Outputs

Now showing 1 - 10 of 13
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    Asymptotic symmetries of Maxwell Chern–Simons gravity with torsion
    (Springer Nature, 2020) ;
    Adami, H.
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    Concha, P.
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    H. R. Safari
    We present a three-dimensional Chern–Simons gravity based on a deformation of the Maxwell algebra. This symmetry allows introduction of a non-vanishing torsion to the Maxwell Chern–Simons theory, whose action recovers the Mielke–Baekler model for particular values of the coupling constants. By considering suitable boundary conditions, we show that the asymptotic symmetry is given by the bms3 ⊕ vir algebra with three independent central charges.
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    Inönü–Wigner contraction and D = 2 + 1 supergravity
    (Springer Nature, 2017) ;
    Concha, P.
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    Fierro, O.
    We present a generalization of the standard Inönü–Wigner contraction by rescaling not only the generators of a Lie superalgebra but also the arbitrary constants appearing in the components of the invariant tensor. The procedure presented here allows one to obtain explicitly the Chern–Simons supergravity action of a contracted superalgebra. In particular we show that the Poincaré limit can be performed to a D = 2 + 1 (p, q) AdS Chern–Simons supergravity in presence of the exotic form. We also construct a new three-dimensional(2, 0) Maxwell Chern–Simons supergravity theory as a particular limit of (2, 0) AdS–Lorentz supergravity theory. The generalization for N = p+q gravitinos is also considered.
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    Lovelock gravities from Born–Infeld gravity theory
    (Elsevier, 2017) ;
    Concha, P.
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    Merino, N.
    We present a Born–Infeld gravity theory based on generalizations of Maxwell symmetries denoted as Cm. We analyze different configuration limits allowing to recover diverse Lovelock gravity actions in six dimensions. Further, the generalization to higher even dimensions is also considered.
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    New family of Maxwell like algebras
    (Elsevier, 2016) ;
    Concha, P.
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    Durka, R.
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    Merino, N.
    We introduce an alternative way of closing Maxwell like algebras. We show, through a suitable change of basis, that resulting algebras are given by the direct sums of the AdS and the Maxwell algebras already known in the literature. Casting the result into the S-expansion method framework ensures the straightaway construction of the gravity theories based on a found enlargement.
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    Pure Lovelock gravity and Chern-Simons theory
    (American Physical Society, 2016) ;
    Concha, P.
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    Durka, R.
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    Inostroza, C.
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    Merino, N.
    We explore the possibility of finding pure Lovelock gravity as a particular limit of a Chern-Simons action for a specific expansion of the AdS algebra in odd dimensions. We derive in detail this relation at the level of the action in five and seven dimensions. We provide a general result for higher dimensions and discuss some issues arising from the obtained dynamics.
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    On the supersymmetric extension of Gauss-Bonnet like gravity
    (Springer Nature, 2016) ;
    Concha, P.
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    Ipinza, M.
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    Raverad, L.
    We explore the supersymmetry invariance of a supergravity theory in the presence of a non-trivial boundary. The explicit construction of a bulk Lagrangian based on an enlarged superalgebra, known as AdS-Lorentz, is presented. Using a geometric approach we show that the supersymmetric extension of a Gauss-Bonnet like gravity is required in order to restore the supersymmetry invariance of the theory.
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    Chern–Simons supergravity in D = 3 and Maxwell superalgebra
    (Elsevier, 2015) ;
    Concha, P.
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    Fierro, O.
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    Salgado, P.
    We present the construction of the D = 3 Chern–Simons supergravity action without cosmological constant from the minimal Maxwell superalgebra sM3. This superalgebra contains two Majorana fermionic charges and can be obtained from the osp(2|1) ⊗ sp(2) superalgebra using the abelian semigroup expansion procedure. The components of the Maxwell invariant tensor are explicitly derived.
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    Generalized Poincaré algebras and Lovelock–Cartan gravity theory
    (Elsevier, 2015) ;
    Concha, P.
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    Peñafiel, D.
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    Salgado, P.
    We show that the Lagrangian for Lovelock–Cartan gravity theory can be reformulated as an action which leads to General Relativity in a certain limit. In odd dimensions the Lagrangian leads to a Chern–Simons theory invariant under the generalized Poincaré algebra B2n+1, while in even dimensions the Lagrangian leads to a Born–Infeld theory invariant under a subalgebra of the B2n+1 algebra. It is also shown that torsion may occur explicitly in the Lagrangian leading to new torsional Lagrangians, which are related to the Chern–Pontryagin character for the B2n+1 group.
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    Generalized supersymmetric cosmological term in N=1 supergravity
    (Springer Nature, 2015) ;
    Concha, P.
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    Salgado, P.
    An alternative way of introducing the supersymmetric cosmological term in a supergravity theory is presented. We show that the AdS-Lorentz superalgebra allows to construct a geometrical formulation of supergravity containing a generalized supersymmetric cosmological constant. The N = 1, D = 4 supergravity action is built only from the curvatures of the AdS-Lorentz superalgebra and corresponds to a MacDowell-Mansouri like action. The extension to a generalized AdS-Lorentz superalgebra is also analyzed.
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    Maxwell superalgebras and Abelian semigroup expansion
    (Elsevier, 2014) ;
    Concha, P.
    The Abelian semigroup expansion is a powerful and simple method to derive new Lie algebras from a given one. Recently it was shown that the S-expansion of so(3, 2) leads us to the Maxwell algebra M. In this paper we extend this result to superalgebras, by proving that different choices of abelian semigroups S lead to interesting D = 4 Maxwell Superalgebras. In particular, the minimal Maxwell superalgebra sM and the N-extended Maxwell superalgebra sM(N ) recently found by the Maurer–Cartan expansion procedure, are derived alternatively as an S-expansion of osp(4|N ). Moreover, we show that new minimal Maxwell superalgebras type sMm+2 and their N-extended generalization can be obtained using the S-expansion procedure.