Effective Orientifolds from Broken Supersymmetry

TL;DR

This paper constructs and analyzes a class of type IIB string theory vacua with broken supersymmetry, characterized by warped compactifications on a five-torus with fluxes, revealing boundary objects and singularities.

Contribution

It completes the analysis of these vacua by identifying boundary objects as effective orientifold planes and characterizing their properties, including tension and charge.

Findings

Presence of an effective O3-plane with negative tension and positive charge.

Determination that tension equals negative charge, T = -Q = Φ.

Identification of a singularity with opposite charge at the other end of the interval.

Abstract

We recently proposed a class of type IIB vacua that yield, at low energies, four--dimensional Minkowski spaces with broken supersymmetry and a constant string coupling. They are compactifications with an internal five-torus bearing a five--form flux $\Phi$ and warp factors depending on a single coordinate. The breaking of supersymmetry occurs when the internal space includes a finite interval. A probe-brane analysis revealed a gravitational repulsion and a charge attraction of equal magnitude from the left end of the interval, and a singularity at the other end. Here we complete the analysis revealing the presence, at one end, of an effective $O3$ of negative tension and positive five--form charge. We also determine the values of these quantities, and show that $T = -\, Q = \Phi$, and characterize the singularity present at the other end of the interval, which hosts an opposite charge. Finally, we discuss various forms of the gravity action in the presence of a boundary and identify a self--adjoint form for its fluctuations.