Black-Bounce in $f(T)$ Gravity

TL;DR

This paper explores new black bounce solutions in $f(T)$ gravity, analyzing their properties with different tetrad choices, and finds violations of energy conditions and novel metric features that challenge existing no-go theorems.

Contribution

It introduces new regular black bounce solutions in $f(T)$ gravity with both diagonal and non-diagonal tetrads, revealing violations of energy conditions and a new metric relation.

Findings

Null torsion solutions violate NEC and other energy conditions.

Solutions are regular across all spacetime regions.

A new metric relation $g_{00}=-g^{11}$ emerges, violating previous no-go theorems.

Abstract

We study new solutions of black bounce spacetimes formulated in $f(T)$ gravity in four dimensions. First, we present the case of a diagonal tetrad, where a constraint arises in the equations of motion, which is divided into the cases of null torsion, constant torsion, and Teleparallel. The Null Energy Condition (NEC) is still always violated, which implies that the other energy conditions are violated. The solutions are regular in all spacetime and the solution with null torsion exhibits discontinuity between the energy conditions outside and inside the event horizon. Second, we present the case of non-diagonal tetrads. This case is divided into a Simpson-Visser type model and a quadratic model. The NEC continues to be violated, implying a violation of the other energy conditions. The solutions are regular in all spacetimes. An interesting result is that due to the possibility that the area associated with the metric is different from $4\pi r^2$, the no-go theorem established in the usual $f(T)$ is violated, appearing the new possibility $g_{00}=-g^{11}$, for the components of the metric.