Challenges for superstring cosmology

Challenges for Superstring Cosmology

We consider whether current notions about superstring theory below the Planck scale are compatible with cosmology. We find that the anticipated form for the dilaton interaction creates a serious roadblock for inflation and makes it unlikely that the universe ever reaches a state with zero cosmological constant and time-independent gravitational constant. Superstring theories have been extensive...

Chaos in superstring cosmology

It is shown that the general solution near a spacelike singularity of the Einstein-dilaton- p-form field equations relevant to superstring theories and M theory exhibits an oscillatory behavior of the Belinskii-Khalatnikov-Lifshitz type. String dualities play a significant role in the analysis.

-Gowdy symmetric IIB superstring cosmology

We show global existence theorems for Gowdy symmetric spacetimes with type IIB stringy matter. The areal and constant mean curvature time coordinates are used. Before coming to that, it is shown that a wave map describes evolution of this system. PACS: 02.30.Jr, 04.20.DW , 04.20.EX , 98.80.Jk

Challenges for Inflationary Cosmology

Inflationary cosmology has provided a predictive and phenomenologically very successful scenario for early universe cosmology. Attempts to implement inflation using scalar fields, however, lead to models with serious conceptual problems. I will discuss some of the problems, explain why string theory could provide solutions to a subset of these problems, and give a brief overview of “string gas ...

Stabilising the dilaton in superstring cosmology