On exponential solutions in the Einstein–Gauss–Bonnet cosmology, stability and variation of G

• Published in: Gravitation & cosmology Vol. 22; no. 3; pp. 245 - 250
• Main Authors: Ernazarov, K. K., Ivashchuk, V. D., Kobtsev, A. A.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.07.2016
• Subjects: Astronomy; Astrophysics and Astroparticles; Classical and Quantum Gravitation; Observations and Techniques; Physics; Physics and Astronomy; Quantum Physics; Relativity Theory
• ISSN: 0202-2893; 1995-0721
• DOI: 10.1134/S0202289316030051

A D -dimensional gravitational model with Gauss–Bonnet and cosmological terms is considered. When an ansatz with a diagonal cosmological metric is adopted, we find new examples of solutions for Λ Λ ≠ 0 and D = 8 with an exponential dependence of the scale factors, which describe expansion of our 3D factor-space and contraction of 4D internal space. We also study the stability of the solutions with static Hubble-like parameters h i and prove that two solutions with Λ = 0 in dimensions D = 22, 28, which were found earlier, are stable. For both solutions we find asymptotic relations for the effective gravitational constant.