Torsion Cosmology of Poincar\'e gauge theory and the constraints of its parameters via SNeIa data

TL;DR

This paper explores a torsion-based cosmological model within Poincaré gauge theory, fitting it to supernova data to analyze universe evolution and constraints on model parameters, suggesting eternal expansion.

Contribution

It provides an analytical study of the SNY torsion cosmology model and constrains its parameters using supernova data, linking theory with observational evidence.

Findings

Best-fit parameters are consistent with ΛCDM at 1σ level.

Universe predicted to expand forever, approaching a halt.

Constraints on model parameters from SNeIa data.

Abstract

Poincar\`e gauge theory (PGT) is an alternative gravity theory, which attempts to bring the gravity into the gauge-theoretic frame, where the Lagrangian is quadratic in torsion and curvature. Recently, the cosmological models with torsion based on this theory have drawn many attentions, which try to explain the cosmic acceleration in a new way. Among these PGT cosmological models, the one with only even parity dynamical modes -- SNY model, for its realistic meaning, is very attractive. In this paper, we first analyze the past-time cosmic evolution of SNY model analytically. And based on these results we fit this model to the most comprehensive SNeIa data (Union 2) and thus find the best-fit values of model parameters and initial conditions, whose related $\chi^{2}$ value is consistent with the one from $\Lambda$CMD at the 1$\sigma$ level. Also by the $\chi^{2}$ estimate, we provide certain constraints on these parameters. Using these best-fit values for the Union 2 SNeIa dataset, we are able to predict the evolution of our real universe over the late time. From this prediction, we know the fate of our universe that it would expand forever, slowly asymptotically to a halt, which is in accordance with the earlier works.