A exact de Sitter cosmological solution of quadratic gravitation with torsion

TL;DR

This paper presents an exact de Sitter-like solution in quadratic gravity with torsion, describing an accelerating universe with a cosmological constant matching observations, and explores torsion's relation to matter energy-momentum.

Contribution

It provides a universal exact de Sitter solution in quadratic gravity with torsion, independent of specific quadratic coefficients, and links torsion generation to matter energy-momentum.

Findings

Describes an accelerating universe with a cosmological constant of observed magnitude.

Shows the solution is universal across a class of quadratic gravity theories.

Torsion is generated by matter energy-momentum when matter is present.

Abstract

A exact de Sitter-like cosmological solution of quadratic gravitation with torsion has been found. In the limit of constant energy and pressure, it becomes a exact de Sitter spacetime. It exists in a wide class of quadratic gravity theories and is the same in vacuum for all the models in this class, no matter how the coefficients of the quadratic terms in the Lagrangian are. It describes an accelerating universe and gives a cosmological constant which is of the order of magnitude of the observed value. In vacuum the universe is a de Sitter spacetime without torsion. When matter presents, however, the spacetime is equipped with curvature as well as torsion. In other wards torsion can be generated by the energy-momentum of matter (energy and pressure).