https://doi.org/10.1140/epjc/s10052-019-7329-8
Regular Article - Theoretical Physics
Exponential cosmological solutions with two factor spaces in EGB model with
revisited
1
Institute of Gravitation and Cosmology, Peoples’ Friendship University of Russia (RUDN University), 6 Miklukho-Maklaya Street, Moscow, 117198, Russian Federation
2
Center for Gravitation and Fundamental Metrology, VNIIMS, 46 Ozyornaya Street, Moscow, 119361, Russian Federation
3
Institute for Nuclear Research of the Russian Academy of Sciences, Moscow, Troitsk, 142190, Russian Federation
* e-mail: ivashchuk@mail.ru
Received:
12
April
2019
Accepted:
20
September
2019
Published online:
8
October
2019
We study exact cosmological solutions in D-dimensional Einstein–Gauss–Bonnet model (with zero cosmological term) governed by two non-zero constants: and
. We deal with exponential dependence (in time) of two scale factors governed by Hubble-like parameters
and h, which correspond to factor spaces of dimensions
and
, respectively, and
. We put
and
. We show that for
there are two (real) solutions with two sets of Hubble-like parameters:
and
, which obey:
, while for
the (real) solutions are absent. We prove that the cosmological solution corresponding to
is stable in a class of cosmological solutions with diagonal metrics, while the solution corresponding to
is unstable. We present several examples of analytical solutions, e.g. stable ones with small enough variation of the effective gravitational constant G, for
.
© The Author(s), 2019