# Cristobal CorralUniversidad Adolfo Ibáñez · Facultad de Artes Liberales

Cristobal Corral

PhD

## About

56

Publications

5,862

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1,156

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Introduction

My research interests are black holes and topologically nontrivial configurations in gravity and field theory, conserved charges, and thermodynamics.

**Skills and Expertise**

Additional affiliations

March 2020 - February 2024

June 2019 - February 2020

January 2017 - January 2019

Education

March 2011 - March 2015

March 2005 - December 2010

## Publications

Publications (56)

We study self-gravitating solutions of three-dimensional massive gravity coupled to the Yang–Mills–Chern–Simons gauge theory. Among these, there is a family of asymptotically Warped-Anti de Sitter black holes that come to generalize previous solutions found in the literature and studied in the context of WAdS $$_3$$ 3 /CFT $$_2$$ 2 . We also presen...

We study the (anti-)self-duality conditions under which the electric and magnetic parts of the conserved charges of the dyonic Kerr-Newman-NUT-AdS solution become equivalent. Within a holographic framework, the stress tensor and the boundary Cotton tensor are computed from the electric/magnetic content of the Weyl tensor. The holographic stress ten...

We study the renormalization of a particular sector of Horndeski theory. In particular, we focus on the nonminimal coupling of a scalar field to the Gauss-Bonnet term and its kinetic coupling to the Einstein tensor. Adopting a power expansion on the scalar
function that couples the Gauss-Bonnet term, we find specific conditions on their coefficient...

A bstract
We construct the first analytic examples of self-gravitating anisotropic merons in the Einstein-Yang-Mills-Chern-Simons theory in three dimensions. The gauge field configurations have different meronic parameters along the three Maurer-Cartan 1-forms and they are topologically nontrivial as the Chern-Simons invariant is nonzero. The corre...

We present a streamlined proof that any Einstein-AdS space is a solution of the Lu, Pang and Pope conformal gravity theory in six dimensions. The reduction of conformal gravity into Einstein theory manifestly shows that the action of the latter can be written as the Einstein-Hilbert term plus the Euler topological density and an additional contribu...

A bstract
We study the renormalization of a particular sector of Horndeski theory. In particular, we focus on the nonminimal coupling of a scalar field to the Gauss-Bonnet term and its kinetic coupling to the Einstein tensor. Adopting a power expansion on the scalar function that couples the Gauss-Bonnet term, we find specific conditions on their c...

We present a novel asymptotically anti–de Sitter black hole solution with conformally-coupled scalar fields in the first-order formalism of gravity in four dimensions. To do so, we consider a one-parameter extension of conformal transformations by exploiting the fact that the tetrad and spin connection are regarded as independent fields. We solve t...

A bstract
In this work, we study (anti-)self duality conditions in unconventional conformal supersymmetry. We focus on a theory constructed in a Townsend-MacDowell-Mansouri form for an SU(2 , 2| N ) gauge connection with matter fields in the adjoint representation. We find bosonic solutions that correspond to analytic gravitational instantons with...

We study the renormalization of a particular sector of Horndeski theory. We focus on the nonminimal coupling of a scalar field to the Gauss-Bonnet term through an arbitrary function of the former plus a kinetic coupling to the Einstein tensor. In the asymptotically AdS sector of the theory, we perform a near-boundary expansion of the fields and we...

We present a streamlined proof that any Einstein-AdS space is a solution of the Lu, Pang and Pope conformal gravity theory in six dimensions. The reduction of conformal gravity into Einstein theory manifestly shows that the action of the latter can be written as the Einstein-Hilbert term plus the Euler topological density and an additional contribu...

We review an algorithm, in the context of gauge and gravity theories described by differential forms, to read off the symmetries of a physical system out of its action, which was originally proposed in [C. Corral and Y. Bonder, Symmetry algebra in gauge theories of gravity, Class. Quantum Grav. 36 (2019) 045002]. In particular, we study the interpl...

We study a conformally coupled scalar-tensor theory with a quartic potential possessing local conformal symmetry up to a boundary term. We show that requiring the restoration of the full local conformal symmetry fixes the counterterms that render the on-shell action finite. The building block of the resulting action is a conformally covariant tenso...

We study the axial anomaly of Dirac spinors on gravitational instanton backgrounds in the context of nonlinear electrodynamics. In order to do so, we consider Einstein gravity minimally coupled to a recently proposed conformal electrodynamics that enjoys duality transformation invariance. These symmetries allow us to generalize the Eguchi-Hanson co...

We study the axial anomaly of Dirac spinors on gravitational instanton backgrounds in the context of nonlinear electrodynamics. In order to do so, we consider Einstein gravity minimally coupled to a recently proposed conformal electrodynamics that enjoys duality transformation invariance. These symmetries allow us to generalize the Eguchi-Hanson co...

A bstract
We present a three-parameter family of analytic black-hole solutions in the bosonic sector of a four-dimensional supersymmetric model with matter fields in the adjoint representation. The solutions are endowed with a curvature and torsional singularities which are both surrounded by an event horizon. They are asymptotically Lorentz flat,...

We study a conformally coupled scalar-tensor theory with a quartic potential possessing local conformal symmetry up to a boundary term. We show that requiring the restoration of the full local conformal symmetry fixes the counterterms that render the on-shell action finite. The building block of the resulting action is a conformally covariant tenso...

We present a three-parameter family of analytic black-hole solutions in the bosonic sector of a four-dimensional supersymmetric model with matter fields in the adjoint representation. The solutions are endowed with a curvature and torsional singularities which are both surrounded by an event horizon. They are asymptotically Lorentz flat, representi...

We construct higher-dimensional generalizations of the Eguchi-Hanson gravitational instanton in the presence of higher-curvature deformations of general relativity. These spaces are solutions to Einstein gravity supplemented with the dimensional extension of the quadratic Chern-Gauss-Bonnet invariant in arbitrary even dimension D ¼ 2m ≥ 4, and they...

We construct higher-dimensional generalizations of the Eguchi-Hanson gravitational instanton in the presence of higher-curvature deformations of general relativity. These spaces are solutions to Einstein gravity supplemented with the dimensional extension of the quadratic Chern-Gauss-Bonnet invariant in arbitrary even dimension $D=2m\geq 4$, and th...

A bstract
We present novel regular Euclidean solutions to General Relativity in presence of Maxwell and conformally coupled scalar fields. In particular, we consider metrics of the Eguchi-Hanson and Taub-NUT families to solve the field equations analytically. The solutions have nontrivial topology labeled by the Hirzebruch signature and Euler chara...

We present novel regular Euclidean solutions to General Relativity in presence of Maxwell and conformally coupled scalar fields. In particular, we consider metrics of the Eguchi-Hanson and Taub-NUT families to solve the field equations analytically. The solutions have nontrivial topology labeled by the Hirzebruch signature and Euler characteristic...

We study conserved charges and thermodynamics of analytic rotating anti-de Sitter black holes with extended horizon topology-also known as black strings-in dynamical Chern-Simons modified gravity. The solution is supported by a scalar field with an axionic profile that depends linearly on the coordinate that spans the string. We compute conserved c...

We study conserved charges, thermodynamics, and phase transitions of analytic rotating anti-de Sitter black holes with extended horizon topology -- also known as black strings -- in dynamical Chern-Simons modified gravity. The solution is supported by a scalar field with an axionic profile that depends linearly on the coordinate that spans the stri...

We study non-Einstein Bach-flat gravitational instanton solutions that can be regarded as the generalization of the Taub-NUT/bolt and Eguchi-Hanson solutions of Einstein gravity to conformal gravity. These solutions include non-Einstein spaces which are either asymptotically locally flat spacetimes or asymptotically locally anti-de Sitter (AlAdS)....

A bstract
It has been recently shown that there is a particular combination of conformal invariants in six dimensions which accepts a generic Einstein space as a solution. The Lagrangian of this Conformal Gravity theory — originally found by Lu, Pang and Pope (LPP) — can be conveniently rewritten in terms of products and covariant derivatives of th...

We study non-Einstein Bach-flat gravitational instanton solutions that can be regarded as the generalization of the Taub-NUT/Bolt and Eguchi-Hanson solutions of Einstein gravity to conformal gravity. These solutions include non-Einstein spaces which are either asymptotically locally flat spacetimes (ALF) or asymptotically locally Anti-de Sitter (Al...

It has been recently shown that there is a particular combination of conformal invariants in six dimensions which accepts a generic Einstein space as a solution. The Lagrangian of this Conformal Gravity theory -originally found by Lu, Pang and Pope (LPP)- can be conveniently rewritten in terms of products and covariant derivatives of the Weyl tenso...

We present different Taub-NUT/bolt-anti de Sitter (AdS) solutions in a shift-symmetric sector of Horndeski theory of gravity possessing nonminimal kinetic coupling of scalar fields to the Einstein tensor. In four dimensions, we find locally and asymptotically locally AdS solutions possessing nontrivial scalar field. In higher dimensions, analytical...

The method of topological renormalization in anti-de Sitter (AdS) gravity consists in adding to the action a topological term which renders it finite, defining at the same time a well-posed variational problem. Here, we use this prescription to work out the thermodynamics of asymptotically locally anti-de Sitter (AlAdS) spacetimes, focusing on the...

The method of topological renormalization in anti-de Sitter (AdS) gravity consists in adding to the action a topological term which renders it finite, defining at the same time a well-posed variational problem. Here, we use this prescription to work out the thermodynamics of asymptotically locally anti-de Sitter (AlAdS) spacetimes, focusing on the...

We present different Taub-NUT/Bolt-anti de Sitter (AdS) solutions in a shift-symmetric sector of Horndeski theory of gravity possessing nonminimal kinetic coupling of scalar fields to the Einstein tensor. In four dimensions, we find locally and asymptotically locally AdS solutions possessing nontrivial scalar field. In higher dimensions, analytical...

Unimodular gravity is an appealing approach to address the cosmological constant problem. In this scenario, the vacuum energy density of quantum fields does not gravitate and the cosmological constant appears merely as an integration constant. Recently, it has been shown that energy diffusion that may arise in quantum gravity and in theories with s...

Unimodular gravity is an appealing approach to address the cosmological constant problem. In this scenario, the vacuum energy density of quantum fields does not gravitate and the cosmological constant appears merely as an integration constant. Recently, it has been shown that energy diffusion that may arise in quantum gravity and in theories with s...

Scalar-tensor gravity theories with a nonminimal Gauss-Bonnet coupling typically lead to an anomalous propagation speed for gravitational waves, and have therefore been tightly constrained by multimessenger observations such as GW170817/GRB170817A. In this paper we show that this is not a general feature of scalar-tensor theories, but rather a cons...

Wheeler's approach to finding exact solutions in Lovelock gravity has been predominantly applied to static spacetimes. This has led to a Birkhoff's theorem for arbitrary base manifolds in dimensions higher than four. In this work, we generalize the method and apply it to a stationary metric ansatz. Using this perspective, we present a Taub-NUT solu...

Wheeler's approach to finding exact solutions in Lovelock gravity has been predominantly applied to static spacetimes. This has led to a Birkhoff's theorem for arbitrary base manifolds in dimensions higher than four. In this work, we generalize the method and apply it to a stationary metric ansatz. Using this perspective, we present a Taub-NUT solu...

A method to find the symmetries of a theory in the first order formalism of gravity is presented. This method is applied to the minimal gravity sector of the Standard Model Extension. It is argued that no inconsistencies arise when Lorentz violation is explicit and the relation between Lorentz violation and invariance under (active) diffeomorphisms...

Four-dimensional homogeneous static and rotating black strings in dynamical Chern–Simons modified gravity, with and without torsion, are presented. Each solution is supported by a scalar field that depends linearly on the coordinate that span the string. The solutions are locally \(\mathrm{AdS}_3\times {\mathbb {R}}\) and they represent the continu...

Diffeomorphisms and an internal symmetry (e.g., local Lorentz invariance) are typically regarded as the symmetries of any geometrical gravity theory, including general relativity. In the first-order formalism, diffeomorphisms can be thought of as a derived symmetry from the so-called local translations, which have improved properties. In this work,...

It is well known that a theory with explicit Lorentz violation is not invariant under diffeomorphisms. On the other hand, for geometrical theories of gravity, there are alternative transformations, which can be best defined within the first-order formalism and that can be regarded as a set of improved diffeomorphisms. These symmetries are known as...

Four dimensional homogeneous anti de-Sitter black string configurations in dynamical Chern-Simons modified gravity, with and without torsion, are presented. These solutions, which are supported by (pseudo)scalar fields depending only on the extended flat coordinate, represent four dimensional black string extensions of the Ba\~nados-Teitelboim-Zane...

It is well known that a theory with explicit Lorentz violation is not invariant under diffeomorphisms. On the other hand, for geometrical theories of gravity, there are alternative transformations, which can be best defined within the first-order formalism, and that can be regarded as a set of improved diffeomorphisms. These symmetries are known as...

Diffeomorphisms and local Lorentz transformations are regarded as the symmetries of most geometrical gravity theories including general relativity. Remarkably, when formulated in the first-order formalism, there is another symmetry, called local translations, with improved properties over the diffeomorphisms. In particular, local translations are f...

Unimodular gravity is an interesting approach to address the cosmological constant problem, since the vacuum energy density of quantum fields does not gravitate in this framework, and the cosmological constant appears as an integration constant. These features arise as a consequence of considering a constrained volume element 4-form, that breaks th...

Up to date, there is no confirmed theoretical explanation for the ultra-high energy cosmic rays (UHECR) beyond the Greisen-Zatsepin-Kuzmin (GZK) limit. In order for these UHECRs to reach the Earth, it is required an extremely suppressed interaction between them and the cosmic microwave background (CMB), which is impossible for standard model (SM) p...

We study the Kaluza-Klein dimensional reduction of the Lovelock-Cartan theory in five-dimensional spacetime, with a compact dimension of S 1 topology. We find cosmological solutions of the Friedmann-Robertson-Walker class in the reduced spacetime. The torsion and the fields arising from the dimensional reduction induce a nonvanishing energy-momentu...

This paper describes the physics case for a new fixed target facility at CERN
SPS. The SHiP (Search for Hidden Particles) experiment is intended to hunt for
new physics in the largely unexplored domain of very weakly interacting
particles with masses below the Fermi scale, inaccessible to the LHC
experiments, and to study tau neutrino physics. The...

We study a scenario allowing a solution of the strong charge parity problem via the Peccei-Quinn
mechanism, implemented in gravity with torsion. In this framework there appears a torsion-related
pseudoscalar field known as the Kalb-Ramond axion. We compare it with the so-called Barbero-Immirzi
axion recently proposed in the literature also in the c...

In the present thesis we have found constraints on the fundamental Planck scale within extra dimensional models, by analyzing the torsion induced four-fermion interaction and the LHC data. Additionally, such an interaction induces corrections to the one-loop observables within the Standard Model (SM) of particle physics, which was used to obtain mo...

We study a scenario allowing a solution of the strong CP-problem via the Peccei–Quinn mechanism, implemented in gravity with torsion. In this framework there appears a torsion-related pseudoscalar field known as Kalb–Ramond axion. We compare it with the so called Barbero-Immirzi axion recently proposed in the literature also in the context of the g...

We study gravity with torsion in extra dimensions and derive an effective
four-dimensional theory containing four-fermion contact operators at the
fundamental scale of quantum gravity in the TeV range. These operators may have
an impact on the low-energy observables and can manifest themselves or can be
constrained in precision measurements. We cal...

It is well known that inclusion of torsion in the gravitational formalism,
leads to four-fermion interactions. Although the coupling constant of this
interaction is strongly suppressed in four dimensions, its value is enhanced in
models with $n$ extra dimensions. In this context, we reinterpret the recent
limits established by LHC experiments to fo...

On this manuscript it is argued the possibility that fermions masses, in
particular quarks, originate through the condensation of a fourth family which
interacts with all of the quarks via a contact four-fermion term coming from
the existence of torsion on the spacetime.

In this paper we consider a simple scenario where the Higgs boson and two
vector resonances are supposed to arise from a new strong interacting sector.
We use the ATLAS measurements of the dijet spectrum to set limits on the masses
of the resonances. Additionally we compute the Higgs boson decay to two photons
and found, when compare to the Standar...

Using the recent limits established by ATLAS to the contact four-fermion
interaction, bounds on the size of the extra dimensions of space-time have been
found, by assuming that the contact interactions come through the inclusion of
torsion in the higher dimensional theory. For two extra dimensions, the limits
are comparable to those in the literatu...