Anisotropic higher derivative gravity and inflationary universe

TL;DR

This paper investigates the stability of inflationary solutions in higher derivative gravity theories using a simplified approach, providing insights into the viability of such models for describing the early universe.

Contribution

It introduces a reduced one-dimensional action method to derive generalized Friedmann equations for complex higher derivative gravity models, facilitating stability analysis.

Findings

Stable inflationary solutions exist with higher derivative terms.

The method simplifies the derivation of field equations in complex models.

Implications for selecting physical theories of the early universe.

Abstract

Stability analysis of the Kantowski-Sachs type universe in pure higher derivative gravity theory is studied in details. The non-redundant generalized Friedmann equation of the system is derived by introducing a reduced one dimensional generalized KS type action. This method greatly reduces the labor in deriving field equations of any complicate models. Existence and stability of inflationary solution in the presence of higher derivative terms are also studied in details. Implications to the choice of physical theories are discussed in details in this paper.