Can String Theory Avoid Cosmological Singularities?

Abstract

We consider the effective action for strings and describe in detail the evolution of a four dimensional homogeneous isotropic universe with matter included. We find that the evolution, which is singular in general, becomes singularity free if during certain Phase of the evolution, when the scale factor increases and the effective string coupling becomes strong, the universe is dominated by solitonic p-branes, p = 0 and/or - 1, or by `matter' for which $(pressure)\le -\frac{1}{\sqrt{3}}(density)$. The mechanism in the case of branes is reminiscent of the recently discovered field theory mechanism where heavy states become light and resolve the moduli space singularities.

14 pages. Latex file

Cited by in corpus (23)

• The Pre-Big Bang Scenario in String Cosmology
• A Critical Review of Classical Bouncing Cosmologies
• Singularity-free cosmological solutions in quadratic gravity
• Boundary Inflation
• Holographic Principle in the Closed Universe : a Resolution with Negative Pressure Matter
• Singularities In Scalar-Tensor Cosmologies
• D-branes and Cosmology
• Non-singular string cosmology in a 2d Hybrid model
• Construction of nonsingular cosmological solutions in string theories
• Wormhole Solutions in Modified Brans-Dicke Theory
• Modified Brans-Dicke cosmology with matter-scalar field interaction
• Cos(M)ological Solutions in M- and String Theory
• The cosmology with the Dp-brane gas
• p-Brane cosmology and phases of Brans-Dicke theory with matter
• Gauss-Bonnet models with cosmological constant and non zero spatial curvature in $D=4$
• Consequences of U dualities for Intersecting Branes in the Universe
• 10 + 1 to 3 + 1 in an Early Universe with mutually BPS Intersecting Branes
• General aspects of Gauss-Bonnet models without potential in dimension four
• Qualitative evolution in higher-loop string cosmology
• Tunneling during Quantum Collapse in AdS Spacetime
• A note on inflationary string cosmology
• Cosmology and Static Spherically Symmetric solutions in D-dimensional Scalar Tensor Theories: Some Novel Features
• Isotropic LQC and LQC--inspired Models with a massless scalar field as Generalised Brans--Dicke theories