Symmetry in Nonlinear Mathematical Physics - 2009
Kirill Bronnikov (Center of Gravitation and Fundamental Metrology,
Russian Research Institute of Metrological Service
& Peoples' Friendship University of Russia, Moscow, Russia)
Nonlinear multidimensional gravity and cosmology
We consider cosmological models in multidimensional gravity with a Lagrangian containing a function of the Ricci scalar as
well as the Ricci tensor squared and the Kretschmann invariant. Spatially flat isotropic cosmologies are built in a Kaluza-Klein
approach with compact extra spaces of arbitrary dimension, with the aid of a slow-change approximation (as compared with the Planck
scale). In particular, in some models with two extra factor spaces, we can obtain scenarios
combining (i) primordial inflation with parameters compatible with the observational data and (ii) modern accelerated expansion,
accompanied by a slow decrease of the effective gravitational constant within
observational limits. This class of models predicts a slow growth of the extra scale factors which should ultimately lead to drastic
changes in the physical laws of our Universe.
This is joint work with S.G. Rubin.