A principle to determine the number (3+1) of large spacetime dimensions
Abstract
We assume that our universe originated from highly excited and interacting strings with coupling constant g_{}=O(1). Fluctuations of spacetime geometry are large in such strings and the physics dictating the emergence of a final spacetime configuration is not known. We propose that, nevertheless, it is determined by an entropic principle that the final spacetime configuration must have maximum entropy for a given amount of energy. This principle implies, under some assumptions, that the spacetime configuration that emerges finally is a (3+1)dimensional FRW universe filled with w=1 perfect fluid and with 6dimensional compact space of size l_{}; in particular, the number of large spacetime dimensions is d=3+1. Such an universe may evolve subsequently into our universe, perhaps as in Banks Fischler scenario.
 Publication:

Physics Letters B
 Pub Date:
 February 2007
 DOI:
 10.1016/j.physletb.2006.11.077
 arXiv:
 arXiv:hepth/0610071
 Bibcode:
 2007PhLB..645..365K
 Keywords:

 High Energy Physics  Theory;
 Condensed Matter  Statistical Mechanics;
 General Relativity and Quantum Cosmology
 EPrint:
 11 pages. Latex file. Version 2: References added