A way of decoupling gravitational sources in pure Lovelock gravity

We provide an algorithm that shows how to decouple gravitational sources in Pure Lovelock gravity. This method allows to obtain several new and known analytic solutions of physical interest in scenarios with extra dimensions and with presence of higher curvature terms. Furthermore, using our method, it is shown that applying the minimal geometric deformation to the Anti de Sitter space time it is possible to obtain regular black hole solutions.Comment: Accepted for publication in Eur.Phys.J.

Thermodynamic extended phase space and P−VP-V criticality of black holes at Pure Lovelock gravity

In this work the \textit{chemistry} of asymptotically AdS black hole, charged and uncharged, solutions of Pure Lovelock gravity is discussed. For this the mass parameter of black holes is identified with the enthalpy of the system together with the promotion of the cosmological constant to a thermodynamics variable proportional to the \textit{pressure} of the system. The equations of state for both, charged and uncharged, are obtained. It is shown that the charged case behaves as a Van der Waals fluid. The existence of a first order phase transition between small stable/large stable black hole, which is a reminiscent of the liquid/gas transition, is found. The critical exponents of the thermal evolution, for different cases of interest, are similar to those of the Van der Waals fluid

New models of 4D4D and Extra dimensional black holes with Localized Sources of Matter and its thermodynamics analysis

The inclusion of Localized sources of matter (LSM) in the energy-momentum tensor has been widely utilized in the construction of regular black holes (RBHs). In this work, we provide a recipe for generating new 4D and extra--dimensional non regular black hole solutions based on the incorporation of LSM. Our proposal, instead of forming a central de Sitter core (as observed in RBHs), leads to the formation of a central integrable singularity, without the presence of an inner horizon (as occurs in RBSs). Based on this recipe, we also present a new 4D and extra-dimensional model (new metric and new energy density) of this type of black hole. Furthermore, it is known that introducing sources of matter into RBHs leads to the formation of a black remnant once the evaporation is completed, preventing complete evaporation down to $r_h=0$. We demonstrate that by introducing our proposed type of matter, the absence of an inner horizon allows for complete evaporation down to $r_h=0$ without the formation of a remnant, both in the $4D$ and the extra-dimensional cases. The complete evaporation of our model also differs from the Schwarzschild vacuum solution, which requires an infinite temperature to reach complete evaporation down to $r_h=0$ in the evaporation process. In our model, complete evaporation is achieved at a finite temperature for the 4D case and at zero temperature for the extra-dimensional case. Our type of LSM induces the appearance of a term of work done by the system on the external environment, denoted as $dW$, in the first law of thermodynamics, i.e. $dU=dM=TdS-dW$, which reduces the usual internal energy change $dU=dM=TdS$. Furthermore, a linear correction to the usual area law of entropy emerges, which differs from the corrections generated by matter in RBHs. In $4D$ scenarios, our entropy correction could be associated with quantum effects through GUP corrections.Comment: Comments are welcom

A note of the first law of thermodynamics by gravitational decoupling

We provide a way of decoupling the first law of thermodynamics in two sectors : the standard first law of thermodynamics and the quasi first law of thermodynamics. It is showed that both sectors share the same thermodynamics volume and the same entropy. However, the total thermodynamics pressure, the total temperature and the total local energy correspond to a simple sum of the thermodynamics contributions of each sector. Furthermore, it is showed a simple example, where there is a phase transition due to the behavior of the temperature at the quasi sector

A new class of regular Black Holes in Einstein Gauss Bonnet gravity with localized sources of matter

We provide a new regular black hole solution (RBH) in Einstein Gauss Bonnet (EGB) gravity with presence of localized sources of matter in the energy momentum tensor. We determinate the necessary constraints in order that the solution to be regular. Although we use a specific form for the energy density as test of prove, these constraints could serve as a recipe for constructing several new RBH solutions in EGB gravity with localized sourced. Due that the usual first law of thermodynamics is not valid for RBH, we rewrite the first law for EGB, which leads to correct values of entropy and volume. The size of the extremal black hole, whose temperature vanishes, becomes smaller for larger dimensions, whose radius could be of order of the Planck units, thus the evaporation would stop once the horizon radius contracts up to a value close to the Planck length, which could be related with the apparition of quantum effects. Furthermore, the presence of matter fields in the energy momentum tensor induces two phase transitions, where there are two regions of stability. This differs from the vacuum EGB solution, where the specific heat is always negative without phase transition as occurs in Schwarzschild black hole

A new model of regular black hole in (2+1)(2+1) dimensions

We provide a new regular black hole solution in $(2+1)$ dimensions with presence of matter fields in the energy momentum tensor, having its core a flat or (A)dS structure. Since the first law of thermodynamics for regular black holes is modified by the presence of the matter fields, we provide a new version of the first law, where a local definition of the variation of energy is defined, and, where the entropy and temperature are consistent with the previously known in literature. It is shown that the signs of the variations of the local definition of energy and of the total energy coincide. Furthermore, at infinite, the usual first law $dM=TdS$ is recovered. It is showed that the formalism used is effective to compute the total energy of regular black holes in $(2+1)$ with presence of matter in the energy momentum tensor. This latter suggests the potential applicability of this formalism to calculate the mass of other models of regular black holes in $d \ge 4$ dimensions.Comment: accepted for publication in EP

Dymnikova-Schwinger traversable wormholes

In this paper, we obtain new $d$-dimensional and asymptotically flat wormhole solutions by assuming a specific form of the energy density distribution. This is addressed by considering the generalization of the so-called Dymnikova model, originally studied in the context of regular black holes. In this way, we find constraints for the involved parameters, namely, the throat radius, the scale associated to the matter distribution, and the spacetime dimension, to build those wormholes. Following, we study the properties of the obtained solutions, namely, embedding diagrams as well as Weak and Null Energy Conditions (WEC and NEC). We show that the larger the dimension, the larger the flatness of the wormhole and the more pronounced the violation of these energy conditions. We also show that the corresponding fluid behaves as phantom-like for $d \geq 4$ in the neighborhood of the wormhole throat. In addition, we specialize the employed model for $d=4$ spacetime, associating it with the gravitational analog of the Schwinger effect in a vacuum and correcting the model by introducing a minimal length via Generalized Uncertainty Principle (GUP). Thus, we obtain a novel traversable and asymptotically flat wormhole solution by considering that the minimal length is very tiny. The associated embedding diagram shows us that the presence of this fundamental quantity increases the slope of the wormhole towards its throat compared with the case without it. That correction also attenuates the WEC (and NEC) violations nearby the throat, with the fluid ceasing to be a phantom-type at the Planck scale, unlike the case without the minimal length.Comment: 18 page