Open string multi-branched and Kahler potentials

TL;DR

This paper explores the structure of scalar potentials in type II string compactifications with fluxes and D-branes, revealing multi-branched potentials and discrete symmetries that influence the Kahler and superpotentials.

Contribution

It introduces a detailed analysis of the multi-branched scalar potential involving open and closed string modes, highlighting the role of discrete shift symmetries in Kahler and superpotentials.

Findings

Multi-branched scalar potential structure identified.

Discrete shift symmetries constrain the superpotential.

Relations between Kahler metrics allow analytical scalar potential derivation.

Abstract

We consider type II string compactifications on Calabi-Yau orientifolds with fluxes and D-branes, and analyse the F-term scalar potential that simultaneously involves closed and open string modes. In type IIA models with D6-branes such potential can be directly computed by integrating out Minkowski three-forms. The result shows a multi-branched structure along the space of lifted open string moduli, in which discrete shifts in special Lagrangian and Wilson line deformations are compensated by changes in the RR flux quanta. The same sort of discrete shift symmetries are present in the superpotential and constrain the Kahler potential. As for the latter, inclusion of open string moduli breaks the factorisation between complex structure and Kahler moduli spaces. Nevertheless, the 4d Kahler metrics display a set of interesting relations that allow to rederive the scalar potential analytically. Similar results hold for type IIB flux compactifications with D7-brane Wilson lines.