Torsional black holes and wormholes in Einstein-Cartan-Maxwell gravity with a conformal scalar field

Abstract

We formulate a one-parameter extension of Weyl transformations in first-order gravity and show that it defines a conformally coupled scalar sector with dynamical torsion. The construction reduces to the standard torsionless conformal coupling in the limit $λ\to 1$. In the corresponding Einstein-Cartan-Maxwell theory, we derive exact static solutions in asymptotically flat and asymptotically locally AdS spacetimes. These solutions describe scalar-dressed black holes, regular black holes, and traversable wormholes, depending on the values of the integration constants and of the deformation parameter. We show that torsion can regularize the scalar field and, for suitable branches, also improve the geometric singularity structure. In the AdS sector, the existence of topological black holes requires a nonvanishing electric charge. These results provide new exact examples of regular and torsional configurations in four-dimensional gravity.