Examinando por Autor "Diaz, Felipe"
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Ítem Accelerating black holes in 2 + 1 dimensions: holography revisited(Springer, 2023-09) Arenas-Henriquez, Gabriel; Cisterna, Adolfo; Diaz, Felipe; Gregory, RuthThis paper studies the holographic description of 2 + 1-dimensional accelerating black holes. We start by using an ADM decomposition of the coordinates suitable to identify boundary data. As a consequence, the holographic CFT lies in a fixed curved background which is described by the holographic stress tensor of a perfect fluid. We compute the Euclidean action ensuring that the variational principle is satisfied in the presence of the domain wall. This requires including the Gibbons-Hawking-York term associated with internal boundaries on top of the standard renormalised AdS3 action. Finally, we compute the entanglement entropy by firstly mapping the solution to the Rindler-AdS spacetime in which the Ryu-Takayanagi surface is easily identifiable. We found that as the acceleration increases the accessible region of the conformal boundary decreases and also the entanglement entropy, indicating a loss of information in the dual theory due to acceleration. © 2023, The Author(s).Ítem Exploring accelerating hairy black holes in 2+1 dimensions: the asymptotically locally anti-de Sitter class and its holography(10298479, 2023-11) Cisterna, Adolfo; Diaz, Felipe; Mann, Robert B.; Oliva, JulioIn the realm of lower-dimensional accelerating spacetimes, it is well-established that the presence of domain walls, which are co-dimension one topological defects, is a necessary condition for their construction. We expand upon the geometric framework employed in the generation of such spacetime solutions by incorporating a conformally coupled scalar field within the matter sector. This endeavor leads to the identification of several new families of three-dimensional accelerating spacetimes with asymptotically locally anti-de Sitter (AdS) behavior. Notably, one of these solutions showcases a hairy generalization of the accelerating BTZ black hole. This solution is constructed at both slow and rapid phases of acceleration, and its connection with established vacuum spacetime models is explicitly elucidated. The inclusion of the scalar field imparts a non-constant Ricci curvature to the domain wall, thereby rendering these configurations particularly suitable for the construction of two-dimensional quantum black holes. To establish a well-posed variational principle in the presence of the domain wall, two essential steps are undertaken. First, we extend the conventional renormalized AdS3 action to accommodate the presence of the scalar field. Second, we explicitly incorporate the Gibbons-Hawking-York term associated with the internal boundaries of our geometries and account for the tension of the domain wall in the action. This dual step process enables us to derive the domain wall field equations via the variational principle. Consequently, the action furnishes the appropriate quantum statistical relation. We engage in holographic computations, thereby determining the explicit form of the holographic stress tensor. In this context, the stress tensor can be expressed as that of a perfect fluid situated on a curved background. Additionally, it paves the road to ascertain the spacetime mass. Finally, we close by demonstrating the existence of three-dimensional accelerating spacetimes with asymptotically locally flat and asymptotically locally de Sitter geometries, particularly those embodying black holes.Ítem Gibbons-Hawking entropy as entanglement entropy(2019-10) Arias, Cesar; Diaz, Felipe; Sundell, PerWe consider a deformed version of four-dimensional de Sitter spacetime. The setup consist of two (antipodal) disconnected Rindler observers, each one with an S4 topology. We show that the two observers have an entanglement entropy, in the low energy sector, given by a quarter of the area of a pair minimal surfaces, that corresponds to the set of fixed points of an Zq orbifold. The result matches with the Gibbons-Hawking entropy when we restrict the Zq action to a single Rindler wedge. © 2019 Author(s).Ítem Logarithmic corrections, entanglement entropy, and UV cutoffs in de Sitter spacetime(Springer Science and Business Media Deutschland GmbH, 2022-08) Arenas Henriquez, Gabriel; Diaz, Felipe; Sundell, PerIt has been argued that the entropy of de Sitter space corresponds to the entanglement between disconnected regions computable by switching on a replica parameter q modeled by the quotient dS/ℤq. Within this framework, we show that the centrally-extended asymptotic symmetry algebra near the cosmic horizon is a single copy of the Virasoro algebra. The resulting density of states matches the semi-classical result of Gibbons and Hawking up to an undetermined constant that is chosen to reproduce the entanglement entropy previously found in the literature. It follows that the logarithmic quantum corrections to the Cardy entropy reproduces the known one-loop result computed in the bulk in the presence of a cutoff. The resulting entanglement entropy follows the divergent area law, where the UV cutoff is now a function of the replica parameter. Thus, as the near-horizon CFT fixes the cutoff in units of the Planck scale, the model can be viewed as a probe into whether the defect Hilbert space has a finite dimension; indeed, the limit q → 0, reproduces Banks’ formula. We also study the quantum corrections of the effective description of the horizon entropy by means of Liouville field theory, where the large q limit corresponds to a realization of dS3/CFT2 correspondence matching the logarithmic corrections to three-dimensional de Sitter space obtained by computing the one-loop contribution to the quantum gravity partition function in the round three-sphere. © 2022, The Author(s).Ítem Prevalence of pre-sarcopenic obesity in Chilean older people. Results of the National Health Survey 2016-2017(Asociacion Espanola de Dietistas-Nutricionistas, 2023) Concha-Cisternasa, Yeny; Diaz, Felipe; Castro-Pinero, Jose; Lanuza, Fabian; Laserre, Nicole; Leiva-Ordohez, Ana Maria; Cigarroa, Igor; Nazar, Gabriela; Parra-Soto, Solange; Celis-Morales, Carlos; Petermann-Rocha, FannyIntroduction: There are no studies in Chile that quantify the prevalence of pre-sarcopenic obesity. Therefore, this study aimed to determine the prevalence of pre-sarcopenic obesity in Chilean older adults.Methodology: 240 people >60 years from the Chilean National Health Survey 2016-2017 were included. Pre-sarcopenia was estimated with the handgrip test and obesity was defined using waist circumference. As a sensitivity analysis, obesity was classified in a subsample of 129 people using body mass index (BMI). Based on the obesity and muscle strength criteria, the participants were categorized as: normal; obesity/ normal; normal/ pre-sarcopenia and obesity/pre-sarcopenia. Results: 22.6% of the population presented obesity/pre-sarcopenia using waist circumference as a diagnostic parameter. The prevalence of pre-sarcopenic obesity was higher in women (22.9%), in older people (33.0%), with urban residence (22.8%), and lower educational levels (37.3%). By incorporating the BMI as an obesity criterion, a decrease in the prevalence of pre-sarcopenic obesity (12.2%) and a higher percentage of women with this phenotype were identified. Conclusions: The prevalence of pre-sarcopenic obesity was identified in 22.6% of the older Chilean population included. Considering the role of obesity and sarcopenia in the development of non-communicable diseases, its identification and early detection could allow the creation of interventions that favours the survival and health of the elderly. © 2023 Asociacion Espanola de Dietistas-Nutricionistas. All rights reserved.Ítem Thermal fluctuations of black holes with non-linear electrodynamics and charged Renyi entropy(Springer, 2023-05-09) Arenas-Henriquez, Gabriel; Diaz, Felipe; Novoa, YerkoWe extend the charged Renyi entropy to a more general holographic scenario. Coupling an arbitrary non-linear electrodynamics Lagrangian density to AdS gravity, we analyse the thermodynamic features of non-linearly charged hyperbolic black holes and the thermal fluctuations in the grand canonical ensemble. We provide a general form for the relevant holographic quantities that describes a CFT with a global U(1) symmetry in terms of horizon data and we compute the first thermal fluctuation of the charged Renyi entropy. We demonstrate the validity of the formulae through an analytic example; the Coulomb source in 2 + 1 dimensions. We propose this model to be dual to charged free bosons in 1 + 1 dimensions. The corrections generates a subleading logarithmic divergence in the entanglement entropy which appear in some Condensed Matter systems with spontaneous symmetry breaking due to IR effects in the ground state. We comment on the possibility of interpreting these results in terms of holography beyond the saddle point approximation. © 2023, The Author(s).