Kalb-Ramond field induced cosmological bounce in generalized teleparallel gravity

TL;DR

This paper demonstrates that Kalb-Ramond fields can induce a cosmological bounce in generalized teleparallel gravity, explaining their current elusiveness and favoring matter bounce scenarios over symmetric ones.

Contribution

It introduces a coupling of Kalb-Ramond fields in teleparallel gravity and shows their role in producing bounce cosmologies with localized energy density near the bounce.

Findings

Kalb-Ramond field energy density is localized near the bounce.

The matter bounce scenario naturally explains the absence of KR fields today.

The work favors matter bounce over symmetric bounce in cosmology.

Abstract

One of the important open questions in high-energy physics is to understand the lack of evidence of Kalb-Ramond (KR) field, in particular in the present day cosmology. In this paper we aim to address this issue by showing that a bounce scenario in the evolution of the Universe strongly advocates their elusiveness, even if their energy density was very large to start with. We consider the Kalb-Ramond field and its effects in the context of generalized teleparallel gravity in (3+1) dimensions. Teleparallel gravity is a description of gravitation in which the tetrads are the dynamical degrees of freedom, and the torsion arising from fields with spin are accommodated naturally as field strength tensors. In order to describe the coupling prescription, we address the correct generalization of the Fock-Ivanenko derivative operator for an n-form tensor field. By varying with respect to the tetrads, this rank-2 field is shown to source the teleparallel equivalent of Einstein's equations. We study the possibility of reproducing two well-known cosmological bounce scenarios, namely, symmetric bounce and matter bounce in four-dimensional spacetime with with the Friedmann-Lemaitre-Robertson-Walker metric and observe that the solution requires the KR field energy density to be localized near the bounce. The crucial result in our work is that this feature also naturally explains the lack of cosmological evidence of the rank-2 field in the present day Universe for the matter-bounce scenario. Thus, among the bouncing cosmologies, latter is favored over the former.