Wormholes and black universes without phantom fields in Einstein-Cartan theory

TL;DR

This paper presents a family of regular solutions in Einstein-Cartan theory with electromagnetic and scalar fields, describing wormholes, black holes, and black universes without phantom fields, all with regular metrics and torsion.

Contribution

It introduces new regular solutions in Einstein-Cartan theory that encompass wormholes, black holes, and black universes without requiring phantom fields.

Findings

Solutions include symmetric and asymmetric wormholes

Existence of regular black holes with multiple horizons

Black universes with de Sitter asymptotics

Abstract

We obtain a family of regular static, spherically symmetric solutions in Einstein--Cartan theory with an electromagnetic field and a nonminimally coupled scalar field with the correct sign of kinetic energy density. At different values of its parameters, the solution, being asemptotically flat at large values of the radial coordinate, describes (i) twice asemptotically flat symmetric wormholes, (ii) asymmetric wormholes with an AdS asymptotic at the "far end", (iii) regular black holes with an extremal horizon or two simple horizons, and (iv) black universes with a de Sitter asymptotic at the "far end". As in other black universe models, it is a black hole as seen by a distant observer, but beyond its horizon there is a nonsingular expanding universe. In all these cases, both the metric and the torsion are regular in the whole space.