Effective Action for Non-Geometric Fluxes from Duality Covariant Actions

TL;DR

This paper develops a duality covariant framework to describe non-geometric flux backgrounds in string theory, introducing new effective actions and analyzing exotic branes and their U-duality properties.

Contribution

It generalizes double and exceptional field theories to include non-geometric backgrounds using dual fields, leading to new effective actions and insights into exotic branes.

Findings

Constructed effective action for non-geometric backgrounds.

Derived U-duality monodromy matrices for exotic branes.

Confirmed charge consistency between flux integrals and monodromy matrices.

Abstract

The (heterotic) double field theories and the exceptional field theories are recently developed for manifestly duality covariant formulation of various supergravity theories, describing low-energy limit of various (heterotic) superstring and M-theory compactifications. These field theories are known to be reduced to the standard descriptions by introducing appropriately parameterized generalized metric and by applying suitably chosen section conditions. We generalize this development to non-geometric backgrounds by utilizing dual fields pertinent to non-geometric fluxes. We introduce different parameterizations for the generalized metric, in terms of the conventional supergravity fields or the dual fields. Under certain simplifying assumptions, we construct new effective action for non-geometric backgrounds. We then obtain the non-geometric backgrounds sourced by exotic branes. From them, we construct their $U$-duality monodromy matrices. The charge of exotic branes obtained from these monodromy matrices agrees perfectly with the charge obtained from the non-geometric flux integral.