Implications of Some Static Spherically Symmetric Graviton-Dilaton Solutions in Brans-Dicke and Low Energy String Theory

S. Kalyana Rama

Submitted on 24 May 1995


Analysing the static, spherically symmetric graviton-dilaton solutions in low energy string and Brans-Dicke theory, we find the following. For a charge neutral point star, these theories cannot predict non trivial PPN parameters, β and γ, without introducing naked singularities. We then couple a cosmological constant Λ as in low energy string theory. We find that only in low energy string theory, a non zero Λ leads to a curvature singularity, which is much worse than a naked singularity. Requiring its absence upto a distance r implies a bound |Λ|<10102(rpc)2 in natural units. If r1Mpc then |Λ|<10114 and, if r1028cm then |Λ|<10122 in natural units.


Comment: 11 pages. Latex File. Invited Talk presented at the XI DAE Symposium held during 21 - 28 December 1994 in Shantiniketan, India

Subjects: High Energy Physics - Theory; Astrophysics; General Relativity and Quantum Cosmology