Bouncing of gravitons emitted from the brane to the bulk back to the brane

Solutions of geodesic equations describing propagation of gravitons in the bulk are studied in a cosmological model with one extra dimension. Brane with matter is embedded in the bulk. It is shown that in the period of early cosmology gravitons emitted from the brane to the bulk under certain conditions can return back to the brane. The model is discussed in two alternative approaches: (i) brane with static metric moving in the AdS space, and (ii) brane located at a fixed position in extra dimension with non-static metric. Transformation of coordinates from the one picture to another is performed. In both approaches conditions for gravitons emitted to the bulk to come back to the brane are found.Comment: LaTeX2e, 12 pages. Refs. added. arXiv admin note: text overlap with arXiv:1204.235

Connection between two forms of extra-dimensional metrics revisited

5D cosmological model with 3-brane with matter is considered. The brane divides bulk in two AdS half spaces. Geometry of the model can be described by two types of coordinates: in the first setting the metric is static and the brane is moving in the bulk, in the second approach the metric is time-dependent and the brane is located at a fixed position in the bulk. Coordinate transformation connecting two coordinate systems is constructed.Comment: 7 page

Constraints on parameters of models with extra dimension from primordial nucleosynthesis

5D models with one 3D brane and one infinite extra dimension are studied. Matter is confined to the brane, gravity extends to the bulk. Models with positive and negative tension of the brane are studied. Cosmological solutions on the brane are obtained by solving the generalized Friedmann equation. As the input in cosmological solutions we use the present-time observational cosmological parameters. We find constraints on dimensionless combinations of scales of 5D models which follow from the requirement that the models reproduce the data on production of ${}^4 He$ in primordial nucleosynthesis.Comment: 12 page