Late-time acceleration and inflation in a Poincaré gauge cosmological model

Abstract

A self-consistent model which can unify Starobinsky inflation and the ΛCDM model in the framework of Poincaré gauge cosmology (PGC) is studied in this work, without extra inflaton and “dark energy”. We start from the general nine-parameter PGC Lagrangian and get two Friedmann-like analytical solutions with the certain ghost- and tachyon-free conditions on the Lagrangian parameters. The scalar torsion h-determined solution is consistent with Starobinsky cosmology in the early-time and the pseudo-scalar torsion f-determined solution contains naturally a constant “dark energy” density, 3(α−1)2/8B0, which covers the ΛCDM model in the late-time. According to the latest observations, we estimate the magnitudes of parameters: α−1 ≃ 8.07 × 10−56, B0 ≃ 5.76 × 10−28 GeV−2 in the natural units.