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

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

Ozgur Akarsu, Ph.D.

Koc University, Dept. of Physics
İstanbul

Özet/Abstract : We present cosmological solutions for (1+3+n)-dimensional steady state universe in dilaton gravity with an arbitrary dilaton coupling constant w and Liouville-type 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 decelerating expansion rate and evolves into accelerating expansion phase subject to the values of w and n, but ends with a Big Rip in all cases. We discuss the cosmological evolution in further detail for the cases w=1 and w=0.5 that permit exact solution. We also comment on how the universe would be conceived by an observer in four dimensions who is unaware of the internal dimensions and considers the conventional general relativity is valid at cosmological scales.

Yer : MSGSÜ Bomonti Binası, Fizik Bölümü.
Tarih : 8 Kasım 2012 Perşembe, 15:00
Ayrıntılı bilgi : msgsufizik.net