An Open String Landscape

TL;DR

This work extends the string landscape to open strings by analyzing how IIB flux backgrounds lift open-string moduli via supersymmetry constraints on D-branes. Using kappa-symmetry, it derives MMMS-type conditions for D-branes in both Calabi-Yau and warped SU(3)-structure backgrounds, showing that fluxes generically discretize open-string vacua into isolated points. It provides local and global analyses of D7-brane moduli, revealing a discrete open-string landscape with a toroidal example illustrating a flux-induced lattice of SUSY locations, and discusses applications to D3-instanton zero modes, geometrical soft terms, and D7-brane model-building. The results offer a framework to count open-string vacua and connect open-string moduli stabilization to phenomenological structures in four dimensions, including potential new mechanisms for adjoint Higgsing and chiral sector realization.

Abstract

The effect of fluxes on open string moduli is studied by analyzing the constraints imposed by supersymmetry on D-branes in type IIB flux backgrounds. We show that generically the conditions of supersymmetry cannot be maintained when moving along the geometrical moduli space of the brane, so that open string moduli are lifted. We argue that there is a disconnected and discrete set of supersymmetric solutions to the open string equations of motion, which extends the familiar closed string landscape to the open string sector.