Q curvature and gravity

In this paper, we consider a family of n-dimensional, higher-curvature theories of gravity whose action is given by a series of dimensionally extended conformal invariants. The latter correspond to higher-order generalizations of the Branson Q curvature, which is an important notion of conformal geometry that has been recently considered in physics in different contexts. The family of theories we study here includes special cases of conformal invariant theories in even dimensions. We study different aspects of these theories and their relation to other higher-curvature theories present in the literature.Fil: Chernicoff, Mariano. Universidad Nacional Autónoma de México; MéxicoFil: Giribet, Gaston Enrique. University of New York; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Grandi, Nicolás Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Lavia, Edmundo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Oliva, Julio. Universidad de Concepción; Chil

Quasinormal modes and black hole hairs in AdS

Holography relates the quasinormal mode frequencies of AdS black holes to the pole structure of the dual field theory propagator. These modes thus provide the timescale for the approach to thermal equilibrium in the CFT. Here, we study how such pole structure and, in particular, the time to equilibrium can get modified in the presence of a black hole hair. More precisely, we consider in AdS a set of relaxed boundary conditions that allow for a low decaying graviton mode near the boundary, which triggers an additional degree of freedom. We solve the scalar field response on such background analytically and nonperturbatively in the hair parameter, and we obtain how the pole structure gets affected by the presence of a black hole hair, relative to that of the usual AdS black hole geometry. The setup we consider is a massive 3D gravity theory, which admits a one-parameter family deformation of Banados-Teitelboim-Zanelli (BTZ) solution and enables us to solve the problem analytically. The theory also admits an AdS 3 soliton which gives a family of vacua that can be constructed from the hairy black hole by means of a double Wick rotation. The spectrum of normal modes on the latter geometry can also be solved analytically; we study its properties in relation to those of the AdS 3 vacuum.Fil: Chernicoff, Mariano. Universidad Nacional Autónoma de México; MéxicoFil: Giribet, Gaston Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Oliva, Julio. Universidad de Concepción; ChileFil: Stuardo, Ricardo. Universidad de Concepción; Chil

Apoyo técnico y control en la construcción del alcantarillado sanitario y pluvial etapa 1, mantenimiento vía Guachucal – Cumbal, construcción puente Cristo Alto resguardo indígena de Muellamués, obras civiles dentro de la oficina de obras públicas del municipio de Guachucal

El presente documento contiene un informe de la pasantía titulada “APOYO TÉCNICO Y CONTROL EN LA CONSTRUCCIÓN DEL ALCANTARILLADO SANITARIO Y PLUVIAL ETAPA 1, MANTENIMIENTO VIA GUACHUCAL – CUMBAL, CONSTRUCCIÓN PUENTE CRISTO ALTO RESGUARDO INDÍGENA DE MUELLAMUES, OBRAS CIVILES DENTRO DE LA OFICINA DE OBRAS PÚBLICAS DEL MUNICIPIO DE GUACHUCAL”. Este informe explica la ejecución de las actividades que se llevaron a cabo en cada una de las obras durante el transcurso de la pasantía. Cada capítulo relata el proceso técnico ejecutado en las diferentes obras, tales como adecuación del terreno y replanteo, excavaciones, entibados, concreto, figurado de acero y diseños. Se incluye fotografías y gráficas. Se utilizaron varios instrumentos de control, mediante el seguimiento de la obra en la cual se realiza una supervisión constante a las labores que diariamente se ejecutan en la obra, aportando de esta forma sus conocimientos, para garantizar así que se cumplan las especificaciones y normativas técnicas, logrando una construcción que cumple los requisitos de calidad, funcionalidad y economía

Chemical potential driven phase transition of black holes in anti-de Sitter space

Einstein-Maxwell theory conformally coupled to a scalar field in D dimensions may exhibit a phase transition at low temperature whose end point is an asymptotically anti-de Sitter black hole with a scalar field profile that is regular everywhere outside and on the horizon. This provides a tractable model to study the phase transition of hairy black holes in anti-de Sitter space in which the backreaction on the geometry can be solved analytically.Fil: Galante, Mariano. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Giribet, Gaston Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina. Université Libre de Bruxelles; Bélgica. Pontificia Universidad Católica de Valparaíso; ChileFil: Goya, Andrés Fabio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: Oliva, Julio. Universidad de Concepción; Chil

Vacua of exotic massive 3D gravity

We consider the recently proposed exotic 3D massive gravity. We show that this theory has a rich space of vacua, including asymptotically Anti de-Sitter (AdS) geometries obeying either the standard Brown-Henneaux boundary conditions or the weakened asymptotic behavior of the so-called Log-gravity. Both sectors contain non-Einstein spaces with SO(2) × ℝ isometry group, showing that the Birkhoff theorem does not hold all over the parameter space, even if strong AdS boundary conditions are imposed. Some of these geometries correspond to 3D black holes dressed with a Log-gravity graviton. We conjecture that such geometries appear in a curve of the parameter space where the exotic 3D massive gravity on AdS3 is dual to a chiral conformal field theory. The theory also contains other interesting vacua, including different families of non-AdS black holes.Instituto de Física La Plat

Slowly rotating and the accelerating α′\alpha'-corrected black holes in four and higher dimensions

We consider the low-energy effective action of string theory at order $\alpha '$, including $R^2$-corrections to the Einstein-Hilbert gravitational action and non-trivial dilaton coupling. By means of a convenient field redefinition, we manage to express the theory in a frame that enables us to solve its field equations analytically and perturbatively in $\alpha '$ for a static spherically symmetric ansatz in an arbitrary number of dimensions. The set of solutions we obtain is compatible with asymptotically flat geometries exhibiting a regular event horizon at which the dilaton is well-behaved. For the 4-dimensional case, we also derive the stationary black hole configuration at first order in $\alpha '$ and in the slowly rotating approximation. This yields string theory modifications to the Kerr geometry, including terms of the form $a$, $a^2$, $\alpha '$ and $a\alpha '$. In addition, we obtain the first $\alpha'$ correction to the C-metrics, which accommodates accelerating black holes. We work in the string frame and discuss the connection to the Einstein frame, for which rotating black holes have already been obtained in the literature.Comment: 19 pages, no figures. v2 21 pages, rotating solution added and title modified, one author added. v3 26 pages, accelerating solution added and title accordingly modified. We have also included the explicit mapping to the Einstein frame that allows to relate our solutions with the ones appearing in previous literature. To appear in PR

Modelling of a piezoelectric beam with a full-bridge rectifier under arbitrary excitation: experimental validation

This paper presents a set of nonlinear differential equations to model a piezoelectric energy harvesting (PEH) system with a full-bridge waveform rectifier (FWR) under arbitrary base excitations. The PEH comprises a piezoelectric element modeled as a current source with a capacitor in parallel, which are connected with an inductor and a resistor. The inductor is proposed to smooth the current generated by the piezoelectric element under rapid mechanical variations and improve the convergence of the set of differential equations. The equations are obtained using piecewise linear modelling for the diodes. The main advantage of this piecewise linear modelling is considering different bias points to represent the nonlinear characteristics of real diodes. Numerical simulations are employed to obtain the optimum inductor value through a comparison with an analytical result, validated with experimental tests. A real case of random acceleration in a bike is applied to the PEH-FWR to evaluate the performance of the proposed equations. They are validated with experiments, a LTspice formulation and a numerical previous one. The proposed formulation can estimate the output DC voltage and energy for a large range of excitation frequencies, including resonant and nonresonant conditions and arbitrary or harmonically externally excited PEHs with FWR.Fil: Febbo, Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; ArgentinaFil: Machado, Sebastián Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Tecnológica Nacional. Facultad Regional Bahía Blanca. Grupo de Investigación en Multifísica Aplicada. - Comisión de Investigaciones Científicas de la Provincia de Buenos Aires. Grupo de Investigación en Multifísica Aplicada; ArgentinaFil: Oliva, Alejandro Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Ortiz, Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Tecnológica Nacional. Facultad Regional Bahía Blanca. Grupo de Investigación en Multifísica Aplicada. - Comisión de Investigaciones Científicas de la Provincia de Buenos Aires. Grupo de Investigación en Multifísica Aplicada; ArgentinaFil: Pereyra, Nicolas. Universidad Nacional del Sur; Argentin

Black hole thermodynamics, conformal couplings, and R-2 terms

Lovelock theory provides a tractable model of higher-curvature gravity in which several questions can be studied analytically. This is the reason why, in the last years, this theory has become the favorite arena to study the effects of higher-curvature terms in the context of AdS/CFT correspondence. Lovelock theory also admits extensions that permit to accommodate matter coupled to gravity in a non-minimal way. In this setup, problems such as the backreaction of matter on the black hole geometry can also be solved exactly. In this paper, we study the thermodynamics of black holes in theories of gravity of this type, which include both higher-curvature terms, U(1) gauge fields, and conformal couplings with matter fields in D dimensions. These charged black hole solutions exhibit a backreacting scalar field configuration that is regular everywhere outside and on the horizon, and may exist both in asymptotically flat and asymptotically Anti-de Sitter (AdS) spaces. We work out explicitly the boundary action for this theory, which renders the variational problem well-posed and suffices to regularize the Euclidean action in AdS. We also discuss several interrelated properties of the theory, such as its duality symmetry under field redefinition and how it acts on black holes and gravitational wave solutions.</p

Expanding the spectrum of SPTLC1-related disorders beyond hereditary sensory and autonomic neuropathies: a novel case of the distinct "S331 syndrome"

Hereditary sensory and autonomic neuropathies (HSAN) encompass a group of peripheral nervous system disorders characterized by remarkable heterogeneity from a clinical and genetic point of view. Mutations in SPTLC1 gene are responsible for HSAN type IA, which usually starts from the second to fourth decade with axonal neuropathy, sensory loss, painless distal ulcerations and mild autonomic features, while motor involvement usually occur later as disease progresses

Historia pre y postdepositacional del entierro secundario del sitio laguna Los Chilenos I (provincia de Buenos Aires)

En este trabajo se analiza la información tafonómica proveniente del Entierro 1 del sitio Laguna Los Chilenos 1 (SO de la provincia de Buenos Aires), de tipo secundario. El mismo constituye una estructura de entierro múltiple (MN1= 14). Mediante el análisis de distintas variables, se intenta inferir su historia pre y postdepositacional. Los principales resultados indican que el tratamiento previo de los individuos que lo integraban fue diferencial, estando éste probablemente condicionado por el lapso transcurrido entre la muerte de cada individuo y la formación del entierro. Diversos agentes postdepositacionales (presión de los sedimentos, raíces, roedores) alteraron el estado de los huesos y su disposición. Sin embargo, se concluye que las diferencias en el grado de integridad anatómica de cada individuo difícilmente podrían ser explicadas por estos factores, siendo probablemente el resultado de contingencias en el proceso de formación del entierro.In this paper the taphonomic information from Burial 1 from Laguna Los Chilenos 1 site (SW Buenos Aires Province) is analyzed. It is a secondary burial and ir constitutes a multiple burial structure (MNI= 14). Its pre and posdepositional history is discussed based on the analysis of several variables. The main results show that the individuals which compase it received differential preburial treatments and probably these were conditioned by the time ranging between the death of each individual and burial formation. Several posdepositional agents (sediment pressure, roots, rodents) altered the state and placement of the bones. Yet, it is concluded that the differences in degree of anatomical integrity for each individual cannot be explained by these factors, and probably resulted from hazards in the process of burial formation.Sociedad Argentina de Antropologí