Observing the Geometry of Warped Compactification via Cosmic Inflation

TL;DR

This paper investigates how the specific geometry of warped compactifications influences cosmic inflation signals, particularly in the context of DBI inflation, revealing that the warp factor shape affects observable CMB features.

Contribution

It demonstrates that the detailed warp geometry leaves observable imprints on the CMB in DBI inflation, highlighting the importance of precise geometric modeling.

Findings

CMB observables depend on the warp factor shape.

Results vary significantly between different warped geometries.

The warp deformed conifold yields distinct inflationary signatures.

Abstract

Using DBI inflation as an example, we demonstrate that the detailed geometry of warped compactification can leave an imprint on the cosmic microwave background (CMB). We compute CMB observables for DBI inflation in a generic class of warped throats and find that the results (such as the sign of the tilt of the scalar perturbations and its running) depend sensitively on the precise shape of the warp factor. In particular, we analyze the warped deformed conifold and find that the results can differ from those of other warped geometries, even when these geometries approximate well the exact metric of the warped deformed conifold.