The Cosmology of Quadratic Torsionful Gravity

Understand

We study the cosmology of a quadratic metric-compatible torsionful gravity theory in the presence of a perfect hyperfluid.

• The gravitational action is an extension of the Einstein-Cartan theory given by the usual Einstein-Hilbert contribution plus all the admitted quadratic parity even torsion scalars and the matter action also exhibits a dependence on the connection.
• The equations of motion are obtained by regarding the metric and the metric-compatible torsionful connection as independent variables.
• We then consider a Friedmann-Lema\^itre-Robertson-Walker background, analyze the conservation laws, and derive the torsion modified Friedmann equations for our theory.