Examinando por Autor "Aros, R."
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Ítem Boundary conditions in first order gravity: Hamiltonian and ensemble(American Physical Society, 2006-01) Aros, R.In this work two different boundary conditions for first order gravity, corresponding to a null and a negative cosmological constant, respectively, are studied. Both boundary conditions allow one to obtain the standard black hole thermodynamics. Furthermore, both boundary conditions define a canonical ensemble. Additionally the quasilocal energy definition is obtained for the null cosmological constant case.Ítem Charges and the boundary in Chern-Simons gravity(American Physical Society, 2006-02) Aros, R.In this work a new set of boundary conditions for Chern-Simons gravity that lead to a fully gauge invariant action is analyzed. This particular form of the action reproduces the standard results of black hole thermodynamics and determines that the algebra of charges of diffeomorphisms at the horizon is the Virasoro algebra.Ítem Conserved charges for even dimensional asymptotically AdS gravity theories(American Physical Society, 2000-08) Aros, R.; Contreras, M.; Olea, R.; Troncoso, R.; Zanelli, J.Mass and other conserved Noether charges are discussed for solutions of gravity theories with locally anti-de Sitter (AdS) asymptotics in 2n dimensions. The action is supplemented with a boundary term whose purpose is to guarantee that it reaches an extremum on the classical solutions, provided the space-time is locally AdS space-time at the boundary. It is also shown that if space-time is locally AdS at spatial infinity, the conserved charges are finite and properly normalized without requiring subtraction of a reference background. In this approach, Noether charges associated with Lorentz and diffeomorphism invariance vanish identically for constant curvature space-times. The case of a zero cosmological constant is obtained as a limit of AdS space-time, where Λ plays the role of a regulator. ©2000 The American Physical Society.Ítem Determinant and Weyl anomaly of Dirac operator: a holographic derivation(2012) Aros, R.; Díaz, D. E.We present a holographic formula relating functional determinants: the fermion determinant in the one-loop effective action of bulk spinors in an asymptotically locally AdS background, and the determinant of the two-point function of the dual operator at the conformal boundary. The formula originates from AdS/CFT heuristics that map a quantum contribution in the bulk partition function to a subleading large-N contribution in the boundary partition function. We use this holographic picture to address questions in spectral theory and conformal geometry. As an instance, we compute the type-A Weyl anomaly and the determinant of the iterated Dirac operator on round spheres, express the latter in terms of Barnes’ multiple gamma function and gain insight into a conjecture by B¨ar and Schopka.Ítem FRW and domain walls in higher spin gravity(Springer Verlag, 2018-03) Aros, R.; Iazeolla, C.; Noreña, J.; Sezgin, E.; Sundell, P.; Yin, Y.We present exact solutions to Vasiliev’s bosonic higher spin gravity equations in four dimensions with positive and negative cosmological constant that admit an interpretation in terms of domain walls, quasi-instantons and Friedman-Robertson-Walker (FRW) backgrounds. Their isometry algebras are infinite dimensional higher-spin extensions of spacetime isometries generated by six Killing vectors. The solutions presented are obtained by using a method of holomorphic factorization in noncommutative twistor space and gauge functions. In interpreting the solutions in terms of Fronsdal-type fields in space-time, a field-dependent higher spin transformation is required, which is implemented at leading order. To this order, the scalar field solves Klein-Gordon equation with conformal mass in (A)dS4. We interpret the FRW solution with de Sitter asymptotics in the context of inflationary cosmology and we expect that the domain wall and FRW solutions are associated with spontaneously broken scaling symmetries in their holographic description. We observe that the factorization method provides a convenient framework for setting up a perturbation theory around the exact solutions, and we propose that the nonlinear completion of particle excitations over FRW and domain wall solutions requires black hole-like states. © 2018, The Author(s).Ítem GJMS-like operators on symmetric 2-tensors and their gravitational duals(2023-02) Aros, R.; Bugin, F.; Diaz, D.E.We study a family of higher-derivative conformal operators P2k(2) acting on transverse-traceless symmetric 2-tensors on generic Einstein spaces. They are a natural generalization of the well-known construction for scalars. We first provide the alternative description in terms of a bulk Poincaré-Einstein metric by making use of the AdS/CFT dictionary and argue that their holographic dual generically consists of bulk massive gravitons. At one-loop quantum level we put forward a holographic formula for the functional determinant of the higher-derivative conformal operators P2k(2) in terms of the functional determinant for massive gravitons with standard and alternate boundary conditions. The analogous construction for vectors P2k(1) is worked out as well and we also rewrite the holographic formula for unconstrained vector and traceless symmetric 2-tensor by decoupling the longitudinal part. Finally, we show that the holographic formula provides the necessary building blocks to address the massless and partially massless bulk gravitons. This is confirmed in four and six dimensions, verifying full agreement with results available in the literature. © 2023, The Author(s).Ítem Logarithmic correction to BH entropy as Noether charge(Springer Verlag, 2010) Aros, R.; Díaz, D.E.; Montecinos, A.We consider the role of the type-A trace anomaly in static black hole solutions to semiclassical Einstein equations in four dimensions. Via Wald’s Noether charge formalism, we compute the contribution to the entropy coming from the anomaly induced effective action and unveil a logarithmic correction to the Bekenstein-Hawking area law. The corrected entropy is given by a seemingly universal formula Sbh = AH 4 − a · χH · φH involving the coefficient a of the type-A trace anomaly, the Euler characteristic χH of the horizon and the value at the horizon φH of the solution to the uniformization problem for Q-curvature. Two instances are examined in detail: Schwarzschild and a four-dimensional massless topological black hole. We also find agreement with the logarithmic correction due to one-loop contribution of conformal fields in the Schwarzschild background.Ítem A note on a gauge–gravity relation and functional determinants(Institute of Physics, 2010) Aros, R.; Díaz, D.E.; Montecinos, A.Abstract We present a refinement of a recently found gauge–gravity relation between one-loop effective actions: on the gauge side, for a massive charged scalar in 2d dimensions in a constant maximally symmetric electromagnetic field; on the gravity side, for a massive spinor in d-dimensional (Euclidean) anti-de Sitter space. The inclusion of the dimensionally regularized volume of AdS leads to a complete mapping within dimensional regularization. In even-dimensional AdS, we acquire a small correction to the original proposal, whereas in dimensional AdS, the mapping is totally new and subtle, with the ‘holographic trace anomaly’ playing a crucial role.Ítem On Renyi entropy for free conformal fields: Holographic and q-analog recipes(Institute of Physics Publishing, 2015-03) Aros, R.; Bugini, F.; Diaz, D.E.We describe a holographic approach to explicitly computing the universal logarithmic contributions to entanglement and Renyi entropies for free conformal scalar and spinor fields on even-dimensional spheres. This holographic derivation proceeds in two steps: first, following Casini and Huerta, a conformal mapping to thermal entropy in a hyperbolic geometry; then identification of the hyperbolic geometry with the conformal boundary of a bulk hyperbolic space and use of an AdS/CFT holographic formula to compute the resultant functional determinant. We explicitly verify the connection with the type-A trace anomaly for the entanglement entropy, whereas the Renyi entropy is computed with the aid of the Sommerfeld formula in order to deal with a conical defect. We show that as a by-product, the log coefficient of the Renyi entropy for round spheres can be efficiently obtained as the q-analog of a procedure similar to the one found by Cappelli and D'Appollonio that rendered the type-A trace anomaly. © 2015 IOP Publishing Ltd.Ítem On the Weyl anomaly of 4D conformal higher spins: a holographic approach(Springer Verlag, 2017-11) Acevedo, S.; Aros, R.; Bugini, F.; Diaz, D.E.We present a first attempt to derive the full (type-A and type-B) Weyl anomaly of four dimensional conformal higher spin (CHS) fields in a holographic way. We obtain the type-A and type-B Weyl anomaly coefficients for the whole family of 4D CHS fields from the one-loop effective action for massless higher spin (MHS) Fronsdal fields evaluated on a 5D bulk Poincaré-Einstein metric with an Einstein metric on its conformal boundary. To gain access to the type-B anomaly coefficient we assume, for practical reasons, a Lichnerowicz-type coupling of the bulk Fronsdal fields with the bulk background Weyl tensor. Remarkably enough, our holographic findings under this simplifying assumption are certainly not unknown: they match the results previously found on the boundary counterpart under the assumption of factorization of the CHS higher-derivative kinetic operator into Laplacians of “partially massless” higher spins on Einstein backgrounds.Ítem On the Weyl anomaly of 4D conformal higher spins: a holographic approach(Journal of High Energy Physics, 2017-11) Acevedo, S.; Aros, R.; Bugini, F.; Diaz, D.E.We present a first attempt to derive the full (type-A and type-B) Weyl anomaly of four dimensional conformal higher spin (CHS) fields in a holographic way. We obtain the type-A and type-B Weyl anomaly coefficients for the whole family of 4D CHS fields from the one-loop effective action for massless higher spin (MHS) Fronsdal fields evaluated on a 5D bulk Poincaré-Einstein metric with an Einstein metric on its conformal boundary. To gain access to the type-B anomaly coefficient we assume, for practical reasons, a Lichnerowicz-type coupling of the bulk Fronsdal fields with the bulk background Weyl tensor. Remarkably enough, our holographic findings under this simplifying assumption are certainly not unknown: they match the results previously found on the boundary counterpart under the assumption of factorization of the CHS higher-derivative kinetic operator into Laplacians of “partially massless” higher spins on Einstein backgrounds. © 2017, The Author(s).Ítem Pontryagin Term and Magnetic Mass in 4D AdS Gravity(Institute of Physics Publishing, 2018-06) Araneda, R.; Aros, R.; Miskovic, O.; Olea, R.In the context of the anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence, 4D AdS gravity is suitably renormalized by adding the Gauss Bonnet term to the Einstein-Hilbert action. The subsequent addition of the Pontryagin term, with a specific coupling, allows to write the on-shell action in terms of the Weyl tensor and its dual, such that the action becomes stationary for asymptotic (anti) self-dual solutions in the Weyl tensor. The addition to the action of both topological invariants mentioned above does not modify the bulk dynamics, but it does modify the expression of the Noether current and, therefore, the conserved quantities of the theory. Here, we show that the method of Iyer and Wald leads to a fully-covariant Noether charge, which contains both the electric and magnetic parts of the Weyl tensor. For configurations which are globally (anti) self-dual in the Weyl tensor, both the action and the Noether charge identically vanish. This means that, for such spacetimes, the magnetic mass is equal to the electric mass. © Published under licence by IOP Publishing Ltd.Ítem The horizon and its charges in the first order gravity(Institute of Physics Publishing, 2003-04) Aros, R.In this work the algebra of charges of diffeomorphisms at the horizon of generic black holes is analyzed within first order gravity. This algebra reproduces the algebra of diffeomorphisms at the horizon, (Diff (S 1)), without a central extension.Ítem Thermodynamic extended phase space and P- V criticality of black holes at Pure Lovelock gravity(Springer, 2020-05) Estrada, M.; Aros, R.In this work the chemistry of asymptotically AdS black hole, for the charged and uncharged solutions of Pure Lovelock gravity, is discussed. The charged case behaves as a Van der Waals fluid and whose first order phase transitions, between small stable/large stable black holes, are analogous to the liquid/gas phase transitions as in AdS black hole for Einstein Hilbert theory. However, the thermodynamics behavior differs from the generic Lovelock theory, because there is a unique critical point, unlike the generic case where there may be more than one critiackcal point. Also, it is shown that the thermodynamics behavior of the Pure Lovelock black holes (in the extended phase space) can be represented by variables that are analytic functions of n and d, where n corresponds to the highest power of the Riemann tensor in the Lagrangian and d corresponds to the number of dimensions. This allows to obtain several results. For instance, the critical compressibility factor Z is a function of n and d that satisfies Z< 1 strictly, matching the behaviour of a real gas, but the new values computed differ from the 3/8 value of a Van der Waals gas except for d= 4 and n= 1. New versions of the Smarr formula and equation of state and its behavior near the critical points are computed, which are also functions of n, d and Z. For all the cases the critical exponent are similar to those of the Van der Waals fluid. The first law of thermodynamics, in the extended space, is deduced by the variation of parameters of the Pure Lovelock solution. The entropy, volume and electric potential are consistent with the previously known results in the literature. © 2020, The Author(s).Ítem Torsion induces gravity(American Physical Society, 2006-04) Aros, R.; Contreras, M.In this work the Poincaré-Chern-Simons and anti-de Sitter-Chern-Simons gravities are studied. For both, a solution that can be cast as a black hole with manifest torsion is found. Those solutions resemble Schwarzschild and Schwarzschild-AdS solutions, respectively.