Late Time Acceleration of the 3-Space in a Higher Dimensional Steady State Universe in Dilaton Gravity

Understand

We present cosmological solutions for (1+3+n)-dimensional steady state universe in dilaton gravity with an arbitrary dilaton coupling constant w and exponential dilaton self-interaction potentials in the string frame.

• We focus particularly on the class in which the 3-space expands with a time varying deceleration parameter.
• We discuss the number of the internal dimensions and the value of the dilaton coupling constant to determine the cases that are consistent with the observed universe and the primordial nucleosynthesis.
• The 3-space starts with a decelerated expansion rate and evolves into accelerated expansion phase subject to the values of w and n, but ends with a Big Rip in all cases.