arXiv subjects

D. F. López

Publications and source records attributed to D. F. López.

6 recordsLinked to original sources

arXiv2026

Horizon Singularities in the Schwarzschild Geometry of the Teleparallel Equivalent of General Relativity

Certain torsion scalar invariants are known to diverge at the horizon of the Schwarzschild solution in the Teleparallel Equivalent of General Relativity (TEGR), obstructing its interpretation as a black hole spacetime. We show that Schwarzschild TEGR geometries split into two distinct subclasses determined by the Lorentz sector of the geometry -- the elements of the tetrad and spin connection not encoded in the metric but appearing in the torsion. In the regular subclass, the divergences are absent and the horizon belongs to the manifold, supporting a consistent black hole interpretation. In the singular subclass, the divergences are genuine and the horizon is excluded from the manifold. As part of this analysis, we clarify the role of inertial contributions in teleparallel gravity, showing that the proper frame does not, by itself, eliminate inertial effects and that the horizon singularities are independent of the inertial structure of the frame. Using three independent approaches -- the inertial frame condition, horizon-penetrating coordinates, and the horizon regularity criterion -- we determine the complete class of Lorentz sector functions compatible with a regular horizon in Schwarzschild TEGR geometries. For this class, all torsion scalar invariants remain finite at the horizon and analytic extensions across it are admitted.

gr-qc↗

arXiv2026

On non-vacuum black holes in new general relativity

New general relativity (NGR) is a torsion-based modification of general relativity whose Lagrangian depends on three free parameters, $(c_{a}, c_{v}, c_{t})$. A subset of the parameter space is physically admissible, namely that which simultaneously ensures ghost-freedom, propagation of a spin-2 mode, and a consistent Newtonian limit. In this work we analyze static and spherically symmetric configurations in NGR, both in vacuum and in the presence of a perfect fluid and an electromagnetic field, under the assumption of the existence of a local black-hole horizon. We find that the mere existence of such configurations forces the free parameters into regions associated with known pathological models: theories that either contain ghost instabilities, do not propagate a spin-2 mode, or lack a Newtonian limit. The remaining geometries are regular at the horizon, so the obstruction is not a breakdown of the geometry but a breakdown of the underlying theory. We therefore conclude that, within the class of models examined, NGR does not admit physically meaningful non-trivial black holes distinct from those of the teleparallel equivalent of general relativity.

gr-qc↗

arXiv2025

De Sitter-Invariant Black Holes

In the de Sitter-invariant approach to gravitation, all solutions to the gravitational field equations are spacetimes that reduce locally to de Sitter. Consequently, besides including an event horizon, the de Sitter-invariant black hole also has a cosmic horizon. Accordingly, it can lodge ordinary and dark energies. Owing to this additional structure concerning Poincaré-invariant general relativity, such a black hole can establish a link between the black hole dynamics and the universe's evolution. Possible implications for cosmology are discussed, and a comparison with recent observations indicating the existence of a cosmological coupling of black holes is presented.

gr-qc↗

arXiv2025

On black holes in new general relativity

New General Relativity (NGR) is a class of teleparallel theories defined by three free parameters, effectively reduced to two after appropriate normalization, which are subject to experimental constraints. In this framework, matter couples minimally to the metric, ensuring that test particles follow geodesics and that null congruence expansions can be employed to detect local horizons. Assuming such horizons exist, we demonstrate that all physically viable NGR models--including the Teleparallel Equivalent of General Relativity (TEGR) and the one-parameter Hayashi and Shirafuji model (1P-H&S)--inevitably exhibit divergences in torsion scalars at the local horizon. This singular behavior obstructs the interpretation of these models and their associated teleparallel geometries as black hole configurations.

gr-qc↗

arXiv2024

De Sitter-invariant approach to cosmology

The spacetime short-distance structure at the Planck scale is governed by the Planck length, usually interpreted as a three-dimensional Euclidian length. As such, it is not Lorentz invariant and clashes with Einstein's special relativity, which is thus unable to describe the Planck scale kinematics. The solution to this problem is twofold. First, one has to re-interpret the Planck length as a Lorentz invariant four-dimensional pseudo-length. Second, to comply with a non-vanishing cosmological term~$Λ$, one has to replace the standard Poincaré-invariant special relativity with the de Sitter-invariant special relativity. Since the Planck pseudo-length does not clash with the de Sitter-invariant special relativity, it provides a consistent description of the Planck scale kinematics in the presence of~$Λ$. Under the above replacement, general relativity changes to the de Sitter-invariant general relativity, in which~$Λ$ is constitutive. In this paper, the ensuing Friedmann equations are derived, and some implications for cosmology are explored and discussed.

gr-qc↗

arXiv2020

An Improved Framework for Quantum Gravity

General relativity has two fundamental problems that render it unsuitable for tackling the gravitational field's quantization. The first problem is the lack of a genuine gravitational variable representing gravitation only, inertial forces apart. The second problem is its incompatibility with quantum mechanics, a problem inherited from the more fundamental conflict of special relativity with quantum mechanics. A procedure to overcome these difficulties is outlined, which amounts to replacing general relativity with its teleparallel equivalent and the Poincaré-invariant special relativity with the de Sitter-invariant special relativity. Those replacements give rise to the de Sitter-modified teleparallel gravity, which does not have the two mentioned problems. It can thus be considered an improved alternative approach to quantum gravity.

gr-qc↗