A nonsingular universe in string cosmology


Al-Nowaiser A. A. , Ozer M. , Taha M. O.

INTERNATIONAL JOURNAL OF MODERN PHYSICS D, vol.8, no.1, pp.43-49, 1999 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 8 Issue: 1
  • Publication Date: 1999
  • Doi Number: 10.1142/s0218271899000055
  • Title of Journal : INTERNATIONAL JOURNAL OF MODERN PHYSICS D
  • Page Numbers: pp.43-49

Abstract

We consider the low-energy effective string action in four dimensions including the leading order-alpha' terms. An exact homogeneous solution is obtained. It represents a nonsingular expanding cosmological model in which the tensor fields tend to Vanish as t --> infinity. The scale factor a(t) of the very early universe in this model has the time dependence a(t)(2) = a(0)(2) + t(2). The violation of the strong energy condition of classical General Relativity to avoid the initial singularity requires that the central charge deficit of the theory be larger than a certain value. The significance of this solution is discussed.