Dynamical solutions in the Nishino–Salam–Sezgin model

Abstract

We investigate the dynamical 3-form flux compactifications and their implications for cosmology in our brane world in the six-dimensional Nishino–Salam–Sezgin model, which is usually referred to as the Salam–Sezgin model. We take the background of the 3-form field acting on the internal space and timelike dimensions without the U(l) gauge field strength. Our solutions are obtained by exchanging the roles of the radial coordinate and the time coordinate from the assumptions made in deriving the previously known static solutions. At the center of the internal space, there is a conical singularity which may be interpreted as our 3-brane world, but it is difficult to realize a warped structure in the direction of the ordinary 3-space. Except for the oscillating solutions, our dynamical evolutions lead to the ever expanding ordinary three-space. However, its expansion rate is not enough to account for the present acceleration of our Universe.