The Universal Kaehler Modulus in Warped Compactifications

TL;DR

This paper constructs the effective theory for the universal Kaehler modulus in warped compactifications, showing that warping does not correct the Kaehler potential and analyzing its behavior beyond linear approximation.

Contribution

It demonstrates that warping does not modify the Kaehler potential and extends the analysis to fully backreacted solutions, providing insights into modulus behavior in warped geometries.

Findings

Warping does not correct the Kaehler potential, only shifts the background volume.

The fully backreacted 10d metric for finite volume fluctuations is computed.

No mixing occurs between the modulus and light Kaluza-Klein modes in warped regions.

Abstract

We construct the effective theory of the universal Kaehler modulus in warped compactifications using the Hamiltonian formulation of general relativity. The spacetime dependent 10d solution is constructed at the linear level for both the volume modulus and its axionic partner, and nontrivial cancellations of warping effects are found in the dimensional reduction. Our main result is that the Kaehler potential is not corrected by warping, up to an overall shift in the background value of the volume modulus. We extend the analysis beyond the linearized approximation by computing the fully backreacted 10d metric corresponding to a finite volume modulus fluctuation. Also, we discuss the behavior of the modulus in strongly warped regions and show that there are no mixings with light Kaluza-Klein modes. These results are important for the phenomenology and cosmology of flux compactifications.