Teleparallel dark energy in a nonflat universe

TL;DR

This study explores how nonflat teleparallel gravity models, with various scalar potentials, fit cosmological data and potentially resolve tensions in current cosmological measurements.

Contribution

It extends teleparallel dark energy models to nonflat geometries, analyzes their dynamics, and compares their fit to observational data against standard cosmology.

Findings

Nonflat models are mildly favored with open geometry.

Models with zero potential outperform ΛCDM in Bayesian criteria.

Teleparallel models align well with local H0 measurements and structure data.

Abstract

In this paper, we investigate the cosmological dynamics of teleparallel dark energy in the presence of nonzero spatial geometry. Extending previous analyses of nonminimal scalar-tensor theories in the torsion-based framework, we consider different scalar field potentials and examine the resulting background evolution and linear perturbations. Adopting a dynamical systems approach, we reformulate the field equations and constrain the model parameters via a Markov chain Monte Carlo analysis combining updated datasets from Pantheon+SH0ES supernovae, cosmic chronometers, and growth rate measurements. Our results suggest a mild preference for an open geometry, although all models remain consistent with a flat universe at the $1\sigma$ level. Notably, Bayesian information criteria indicate that the nonflat teleparallel scenario with a vanishing potential is strongly favored over the standard $\Lambda$CDM model. Furthermore, all teleparallel scenarios are compatible with local determinations of the Hubble constant and exhibit better agreement with low-redshift structure formation data compared to $\Lambda$CDM. These findings highlight the potential of nonflat teleparallel gravity to address current observational tensions and motivate its further investigation as a viable alternative to standard cosmology.