Universidad Complutense de Madrid

Hamiltonian formalism, master functions and Darboux transformations for perturbed (interiors and exteriors of) nonrotating black holes

Michele Lenzi, Guillermo A. Mena Marugán, Andrés Mínguez-Sánchez +1

Motivated by their relevance to the interior of nonrotating black holes, classical and quantum Kantowski-Sachs cosmologies have recently attracted increasing attention. This intere…

Cosmological properties of black-hole hair in the linearly coupled scalar-Gauss-Bonnet theory

Dražen Glavan, Darío Jaramillo-Garrido

We investigate the superhorizon behavior of scalar hair sourced by black holes in de Sitter spacetime in the linearly coupled shift-symmetric scalar-Gauss-Bonnet theory. Working in…

gr-qc2026★ 1 cited

Regular Black Holes in General Relativity from Nonlinear Electrodynamics with de Sitter Cores

A. A. Araújo Filho, Ednaldo L. B. Junior, José Tarciso S. S. Junior +6

We present new regular black hole solutions in general relativity (GR) within a static, spherically symmetric framework governed by a variable equation of state, following the appr…

Finite time pseudo-rip singularity in cosmology

Mariusz P. Dąbrowski, Teodor Borislavov Vasilev

By studying first a new decelerating sudden future singularity (SFS) universe we report finding a novel type of cosmological singularity which we dub a finite time pseudo-rip (FTPR…

Effects of massive spin-2 fields on gravitational wave propagation

Jose A. R. Cembranos, Álvaro Cendal, Hector Villarrubia-Rojo

Massive spin-2 fields in addition to the standard massless graviton arise naturally in extensions of general relativity, such as massive bigravity or models with extra dimensions.…

Matter environments around black holes: geodesics, light rings, and ultracompact configurations

Dylan S. Fonseca, Caio F. B. Macedo, Mateus Malato Corrêa +1

Astrophysical black holes are invariably embedded in matter environments whose gravitational influence can alter key strong-field features of the spacetime. In this work, we invest…

Spinning extremal dyonic black holes in $γ = 1$ Einstein-Maxwell-dilaton theory

Jose Luis Blázquez-Salcedo, Carlos Herdeiro, Eugen Radu +2

We propose a general framework for the study of asymptotically flat spinning dyonic {\it extremal} black holes (eBHs) in $D = 4$ Einstein-Maxwell-dilaton theory. Restricting to the s…

gr-qc2025

Hydrodynamical Misner-Sharp Formulation for Gravitational Collapse in Scalar-Tensor Theories

Jose A. R. Cembranos, Luis Diaz-Gimenez

We study the problem of gravitational collapse in the context of scalar-tensor theories of Gravity. We introduce a new hydrodynamical formulation in the Einstein frame, inspired by…

gr-qc2025

Radial perturbations of charged wormholes

Jose Luis Blázquez-Salcedo, Luis Manuel González-Romero, Fech Scen Khoo +2

Ellis-Bronnikov wormholes suffer from an unstable radial mode. Here we investigate the evolution of the unstable mode(s) for charged wormholes. We show that the instability remains…

Quadrupole perturbations of slowly spinning Ellis-Bronnikov wormholes

Bahareh Azad, Jose Luis Blázquez-Salcedo, Fech Scen Khoo +2

We study the axial and polar perturbations of slowly rotating Ellis-Bronnikov wormholes in General Relativity, applying a perturbative double expansion. In particular, we derive th…

Gravity from equilibrium thermodynamics of stretched light cones

Ana Alonso-Serrano, Luis J. Garay, Marek Liška +1

This work digs into the connection between gravity and thermodynamics of stretched light cones (SLC). They are associated with uniformly accelerating observers, who endow the SLC w…

K-nonizing

Jose Beltrán Jiménez, Teodor Borislavov Vasilev, Darío Jaramillo-Garrido +2

We unveil the dynamical equivalence of field theories with non-canonical kinetic terms and canonical theories with a volume element invariant under transverse diffeomorphisms. The…

gr-qc2025★ 4 cited

Accretion dynamics in black holes with spontaneous Lorentz symmetry breaking

Daniela S. J. Cordeiro, Ednaldo L. B. Junior, José Tarciso S. S. Junior +6

We investigate the spherical accretion of various types of fluids onto a Schwarzschild-like black hole solution modified by a Kalb-Ramond field implementing spontaneous Lorentz sym…

Multifield theories invariant under transverse diffeomorphisms: The mixed regime case

Antonio L. Maroto, Prado Martín-Moruno, Diego Tessainer

We study theories breaking diffeomorphism (Diff) invariance down to the subgroup of transverse diffeomorphisms (TDiff), consisting of multiple scalar fields in a cosmological backg…

Estimation of gravitational production uncertainties

Jose A. R. Cembranos, Luis J. Garay, Álvaro Parra-López +1

Cosmological production of scalar, non-minimally coupled dark matter depends on the specifics of the inflationary model under consideration. We analyze both Starobinsky inflation a…

Gravitational wave propagation in generalized hybrid metric-Palatini gravity

Cláudio Gomes, João Luís Rosa, Miguel A. S. Pinto

In this work we analyze the propagation properties of gravitational waves in the hybrid metric-Palatini gravity theory. We introduce the scalar-tensor representation of the theory…

gr-qc2025★ 5 cited

Screening Mechanisms on White Dwarfs: Symmetron & Dilaton

Joan Bachs-Esteban, Ilídio Lopes, Javier Rubio

This work provides the first comparison of the symmetron and dilaton fields in white dwarfs. We show how these screening mechanisms behave inside {such stars} and their impact on s…

gr-qc2025

Black hole thermodynamics probes the equivalence principle

Ana Alonso-Serrano, Luis J. Garay, Marek Liška

The equivalence principle for test gravitational physics strongly constrains dynamics of spacetime, providing a powerful criterion for selecting candidate theories of gravity. Howe…

gr-qc2025★ 4 cited

Relevance of "on" and "off" transitions in quantum pair production experiments

Álvaro Álvarez-Domínguez, Álvaro Parra-López

Analog gravity experiments, such as those realized in Bose-Einstein condensates, often aim at simulating cosmological pair production due to the dynamical expansion of the Universe…

gr-qc2025★ 5 cited

Traversable wormholes with multiple unstable critical curves

A. Rueda, E. Contreras

The number and position of unstable critical curves, as well as the nature of the accretion disk around compact objects, play a fundamental role in their optical appearance. Identi…