Asymptotic Cosmological Behavior of Scalar-Torsion Mode in Poincare Gauge Theory

Abstract

We study the cosmological effect of the simple scalar-torsion ($0^{+}$) mode in Poincaré gauge theory of gravity. We find that for the non-constant (affine) curvature case, the early evolution of the torsion density ${\rho }_T$ has a radiation-like asymptotic behavior of $a^{-4}$ with $a$ representing the scale factor, along with the stable point of the torsion pressure ($P_T$) and density ratio $P_T/{\rho }_T\to 1/3$ in the high redshift regime $(z\gg 0)$, which is different from the previous result in the literature. We use the Laurent expansion to resolve the solution. We also illustrate our result by the execution of numerical computations.

9 pages, 2 figures, accepted by PRD