On stable exponential solutions in Einstein-Gauss-Bonnet cosmology with zero variation of G

TL;DR

This paper finds and proves the stability of exponential cosmological solutions in Einstein-Gauss-Bonnet gravity with zero variation of G, featuring specific submanifold dimensions and exponential expansion of our 3D space.

Contribution

It introduces new stable exponential solutions with zero G variation in Einstein-Gauss-Bonnet cosmology for specific dimensions and cosmological parameters.

Findings

Solutions with exponential scale factors for certain (m,l) dimensions.

Stable solutions with zero variation of G.

Explicit conditions for Hubble parameters H and h.

Abstract

A D-dimensional gravitational model with a Gauss-Bonnet term and the cosmological term Lambda is considered. Assuming diagonal cosmological metrics, we find, for certain non-zero Lambda new examples of solutions with an exponential time dependence of two scale factors, governed by two Hubble-like parameters H > 0 and h < 0, corresponding to submanifolds of dimensions m and l, respectively, with (m,l) = (4,2), (5,2), (5,3), (6,7), (7,5), (7,6) and D = 1 + m + l. Any of these solutions describes an exponential expansion of "our" 3-dimensional factor-space with Hubble parameter H and zero variation of the effective gravitational constant G. We also prove the stability of these solutions in the class of cosmological solutions with diagonal metrics.