Generalized hybrid metric-Palatini gravity

TL;DR

This paper proposes a new class of modified gravity theories that depend on both metric and Palatini curvature scalars, establishing their equivalence to scalar-tensor theories and analyzing their cosmological dynamics.

Contribution

It introduces a generalized hybrid metric-Palatini gravity framework and proves its dynamical equivalence to bi-scalar field theories, expanding the scope of modified gravity models.

Findings

The theory is dynamically equivalent to a non-minimally coupled bi-scalar field model.

Cosmological solutions exhibit diverse behaviors analyzed via dynamical systems.

The approach broadens the landscape of viable modified gravity theories.

Abstract

We introduce a new approach to modified gravity which generalizes the recently proposed hybrid metric-Palatini gravity. The gravitational action is taken to depend on a general function of both the metric and Palatini curvature scalars. The dynamical equivalence with a non-minimally coupled bi-scalar field gravitational theory is proved. The evolution of cosmological solutions is studied using dynamical systems techniques.