Static spherically symmetric black holes in weak f(T)-gravity

TL;DR

This paper investigates how weak teleparallel perturbations affect spherically symmetric black hole solutions in gravity, comparing observable predictions to general relativity and discussing implications for black hole physics and constraints on teleparallel theories.

Contribution

It derives the most general static vacuum solutions in weak f(T)-gravity and analyzes their observable differences from Schwarzschild black holes, expanding understanding of teleparallel black hole models.

Findings

Existence of solutions with weaker observational bounds on teleparallel gravity.

Differences in photon sphere, light deflection, and perihelion shift compared to GR.

Discussion on how perturbations influence Hawking evaporation.

Abstract

With the advent of gravitational wave astronomy and first pictures of the "shadow" of the central black hole of our milky way, theoretical analyses of black holes (and compact objects mimicking them sufficiently closely) have become more important than ever. The near future promises more and more detailed information about the observable black holes and black hole candidates. This information could lead to important advances on constraints on or evidence for modifications of general relativity. More precisely, we are studying the influence of weak teleparallel perturbations on general relativistic vacuum spacetime geometries in spherical symmetry. We find the most general family of spherically symmetric, static vacuum solutions of the theory, which are candidates for describing teleparallel black holes which emerge as perturbations to the Schwarzschild black hole. We compare our findings to results on black hole or static, spherically symmetric solutions in teleparallel gravity discussed in the literature, by comparing the predictions for classical observables such as the photon sphere, the perihelion shift, the light deflection, and the Shapiro delay. On the basis of these observables, we demonstrate that among the solutions we found, there exist spacetime geometries that lead to much weaker bounds on teleparallel gravity than those found earlier. Finally, we move on to a discussion of how the teleparallel perturbations influence the Hawking evaporation in these spacetimes.