×

Randall-Sundrum brane cosmology: modification of late-time cosmic dynamics by exotic matter. (English) Zbl 1217.83055

Summary: We show, through the study of concrete examples, that depending on the cosmic dynamics of the energy density of matter degrees of freedom living in the brane, Randall-Sundrum (RS) brane effects can be important not only at short distances (UV regime), but also at large cosmological scales (IR regime). Our first example relies on the study, by means of the dynamical system tools, of a toy model based in a nonlinear electrodynamics (NLED) Lagrangian. Then we show that other, less elaborated models, such as the inclusion of a scalar phantom field, and of a tachyon phantom field-trapped in the brane-produce similar results. The form of the RS correction seems to convert what would have been future attractors in general relativity into saddle points. The above ‘mixing of scales’ effect is distinctive only of theories that modify the right-hand side (matter part) of the Friedmann equation, so that, for instance, Dvali-Gabadadze-Porrati-brane models do not show this feature.

MSC:

83F05 Relativistic cosmology
83E30 String and superstring theories in gravitational theory
81T30 String and superstring theories; other extended objects (e.g., branes) in quantum field theory
83D05 Relativistic gravitational theories other than Einstein’s, including asymmetric field theories
83C55 Macroscopic interaction of the gravitational field with matter (hydrodynamics, etc.)
85A40 Astrophysical cosmology
83C75 Space-time singularities, cosmic censorship, etc.