In this work, the role of a time-varying Newton constant under the scale-dependent approach is investigated in the thermodynamics of the Friedman equations. In particular, we show that the extended Friedman equations can be derived either from equilibrium thermodynamics when the non-matter energy momentum tensor is interpreted as a fluid or from non-equilibrium thermodynamics when an entropy production term, which depends on the time-varying Newton constant, is included. Finally, a comparison between black hole and cosmological thermodynamics in the framework of scale-dependent gravity is briefly discussed.

Spain

Pedro Bargueño

Ecuador

Ernesto Contreras

Chile

Ángel Rincón

Thermodynamics of scale-dependent Friedmann equations

In the present paper, we analyze the well-known 2+1 dimensional black holes (assuming a non-vanishing cosmological constant) in light of the gravitational decoupling by the minimal geometric deformation approach. To illustrate our results, we consider the BTZ geometry as the seed solution to generate new anisotropic ones. To complement the study, the curvature scalars and the energy conditions are analyzed.

Francisco Tello-Ortiz

Venezuela

Gabriel Abellán

Anisotropic 2+1 dimensional black holes by gravitational decoupling

In this work, we investigate five-dimensional scale-dependent black hole solutions by modelling their event horizon with some of the eight Thurston three-dimensional geometries. Specifically, we construct constant curvature scale-dependent black holes and also the more exotic scale-dependent Solv black hole. These new solutions are obtained by promoting both the gravitational and the cosmological couplings to r-dependent functions, in light of a particular description of the effective action inspired by the high energy philosophy. Interestingly, the so-called running parameter, together with the topology of the event horizon, control the asymptotic structure of the solutions found. Finally, differences in both the entropy and the temperature between the classical and the scale-dependent Solv black hole are briefly commented.

Five-dimensional scale-dependent black holes with constant curvature and Solv horizons

This article is devoted to the study of new exact analytical solutions in the background of Reissner–Nordström space-time by using gravitational decoupling via minimal geometric deformation approach. To do so, we impose the most general equation of state, relating the components of the $$\theta $$ <math><mi>θ</mi></math> -sector in order to obtain the new material contributions and the decoupler function f(r). Besides, we obtain the bounds on the free parameters of the extended solution to avoid new singularities. Furthermore, we show the finitude of all thermodynamic parameters of the solution such as the effective density $${\tilde{\rho }}$$ <math><mover><mi>ρ</mi><mo>~</mo></mover></math> , radial $${\tilde{p}}_{r}$$ <math><msub><mover><mi>p</mi><mo>~</mo></mover><mi>r</mi></msub></math>  and tangential $${\tilde{p}}_{t}$$ <math><msub><mover><mi>p</mi><mo>~</mo></mover><mi>t</mi></msub></math>  pressure for different values of parameter $$\alpha $$ <math><mi>α</mi></math>  and the total electric charge Q. Finally, the behavior of some scalar invariants, namely the Ricci R and Kretshmann $$R_{\mu \nu \omega \epsilon }R^{\mu \nu \omega \epsilon }$$ <math><mrow><msub><mi>R</mi><mrow><mi>μ</mi><mi>ν</mi><mi>ω</mi><mi>ϵ</mi></mrow></msub><msup><mi>R</mi><mrow><mi>μ</mi><mi>ν</mi><mi>ω</mi><mi>ϵ</mi></mrow></msup></mrow></math>  scalars are analyzed. It is also remarkable that, after an appropriate limit, the deformed Schwarzschild black hole solution always can be recovered.

Luciano Gabbanelli

Minimal geometric deformation in a Reissner–Nordström background

In this work, starting from a spherically symmetric polytropic black hole, a rotating solution is obtained by following the Newman–Janis algorithm without complexification. Besides studying the horizon, the static conditions and causality issues of the rotating solution, we obtain and discuss the shape of its shadow. Some other physical features as the Hawking temperature and emission rate of the rotating polytropic black hole solution are also discussed.

J. Ramirez–Velasquez

Portugal

Grigoris Panotopoulos

Colombia

Black hole shadow of a rotating polytropic black hole by the Newman–Janis algorithm without complexification

In this work we implement the Minimal Geometric Deformation decoupling method to obtain general static interior solutions for a BTZ vacuum from the most general isotropic solution in $$2+1$$ <math><mrow><mn>2</mn><mo>+</mo><mn>1</mn></mrow></math>  dimensions including the cosmological constant $$\varLambda $$ <math><mi>Λ</mi></math> . We obtain that the general solution can be generated only by the energy density of the original isotropic sector, so that this quantity plays the role of a generating function. Although as a particular example we study the static star with constant density, the method here developed can be easily applied to more complex situations described by other energy density profiles.

A general interior anisotropic solution for a BTZ vacuum in the context of the minimal geometric deformation decoupling approach

In this work we study steady and spherical relativistic dust accretion onto a static and spherically symmetric scale-dependent black hole. In particular we consider a polytropic scale-dependent black hole as a central object and obtain that the radial velocity profile and the energy density are affected when scale-dependence of the central object is taken into account and such a deviation is controlled by the so called running parameters of the scale-dependence models.

J. Ramírez-Velásquez

Relativistic dust accretion onto a scale-dependent polytropic black hole

In the context of the minimal geometric deformation method, in this paper we implement the inverse problem in a black hole scenario. In order to deal with an anisotropic polytropic black hole solution of the Einstein field equations with cosmological constant, the deformation method is slightly extended. After obtaining the isotropic sector and the decoupler for an anisotropic (A-)dS polytropic black hole solution, we emphasize a possible relation between anisotropization/isotropization and the violation of the energy conditions.

Minimal geometric deformation in asymptotically (A-)dS space-times and the isotropic sector for a polytropic black hole

In this paper we show that any static and spherically symmetric anisotropic solution of the Einstein field equations can be thought as a system sourced by certain deformed isotropic system in the context of Minimal Geometric Deformation-decoupling approach. To be more precise, we developed a mechanism to obtain an isotropic solution from any anisotropic solution of the Einstein field equations. As an example, we implement the method to obtain the sources of a simple static anisotropic and spherically symmetric traversable wormhole.

Minimal Geometric Deformation: the inverse problem

In this work we extend and generalize our previous work on the scale dependence at the level of the effective action of black holes in the presence of non-linear electrodynamics. In particular, we consider the Einstein-power-Maxwell theory without a cosmological constant in ($$2+1$$ <math><mrow><mn>2</mn><mo>+</mo><mn>1</mn></mrow></math> ) dimensions, assuming a scale dependence of both the gravitational and the electromagnetic coupling and we investigate in detail how the scale-dependent scenario affects the horizon and thermodynamic properties of the classical black holes for any value of the power parameter. In addition, we solve the corresponding effective field equations imposing the “null energy condition” in order to obtain analytical solutions. The implications of quantum corrections are also briefly discussed.

Benjamin Koch

Grigorios Panotopoulos

Scale-dependent ($$2+1$$ <math><mrow><mn>2</mn><mo>+</mo><mn>1</mn></mrow></math> )-dimensional electrically charged black holes in Einstein-power-Maxwell theory