A nonsingular universe in string cosmology
INTERNATIONAL JOURNAL OF MODERN PHYSICS D, cilt.8, sa.1, ss.43-49, 1999 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 8 Sayı: 1
- Basım Tarihi: 1999
- Doi Numarası: 10.1142/s0218271899000055
- Dergi Adı: INTERNATIONAL JOURNAL OF MODERN PHYSICS D
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Sayfa Sayıları: ss.43-49
- Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu
- Yıldız Teknik Üniversitesi Adresli: Hayır
Özet
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.