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Abstract:

In effective supergravity theories following from the superstring, a modulus field can quite naturally set the neccessary initial conditions for successful cosmological inflation to be driven by a hidden sector scalar field. The leading term in the scalar potential is {\em cubic} hence the spectrum of scalar density perturbations neccessarily deviates from scale-invariance, while the generation of gravitational waves is negligible. The growth of large-scale structure is then consistent with observational data assuming a critical density cold dark matter universe, with no need for a component of hot dark matter. The model can be tested thorough measurements of cosmic microwave background anisotropy on small angular scales.

Abstract:

We identify a new mechanism in supergravity theories which leads to successful inflation without any need for fine tuning. The simplest model yields a spectrum of density fluctuations tilted away from scale-invariance and negligible gravitational waves. We demonstrate that this is consistent with the observed large-scale structure for a cold dark matter dominated, critical density universe. The model can be tested through measurements of microwave background anisotropy on small angular scales.