Chaotic inflation in higher derivative gravity theories

Understand

In this paper, we investigate chaotic inflation from scalar field subjected to potential in the framework of $f(R^2, P, Q)$-gravity, where we add a correction to Einstein's gravity based on a function of the square of the Ricci scalar $R^2$, the contraction of the Ricci tensor $P$, and the contraction of the Riemann tensor $Q$.

• The Gauss-Bonnet case is also discussed.
• We give the general formalism of inflation, deriving the slow-roll parameters, the $e$-folds number, and the spectral indexes.
• Several explicit examples are furnished, namely we will consider the cases of massive scalar field and scalar field with quartic potential and some power-law function of the curvature invariants under investigation in the gravitational action of the theory.