An Alternative Interpretation for the Moduli Fields of the Cosmology Associated to Type IIB Supergravity with Fluxes

TL;DR

This paper proposes interpreting the dilaton in a type IIB supergravity cosmological model as dark matter, leading to predictions similar to the Lambda-CDM model in linear regimes but with notable differences in galaxy formation and structure.

Contribution

It introduces an alternative interpretation of the dilaton as dark matter, contrasting with the usual Quintessence view, and explores its implications for cosmology and galaxy formation.

Findings

Similar evolution to Lambda-CDM in linear structure formation

Earlier galaxy formation predicted by the supergravity model

Absence of density cusps in galaxy centers

Abstract

We start with a particular cosmological model derived from type IIB supergravity theory with fluxes, where usually the dilaton is interpreted as a Quintessence field. Instead of that, in this letter we interpret the dilaton as the dark matter of the universe. With this alternative interpretation we find that in this supergravity model gives a similar evolution and structure formation of the universe compared with the $\Lambda$CDM model in the linear regime of fluctuations of the structure formation. Some free parameters of the theory are fixed using the present cosmological observations. In the non-linear regimen there are some differences between the type IIB supergravity theory with the traditional CDM paradigm. The supergravity theory predicts the formation of galaxies earlier than the CDM and there is no density cusp in the center of galaxies. These differences can distinguish both models and can give a distinctive feature to the phenomenology of the cosmology coming from superstring theory with fluxes.