Non-supersymmetric infrared perturbations to the warped deformed conifold

TL;DR

The paper investigates non-supersymmetric perturbations of the Klebanov-Strassler warped throat, focusing on IR perturbations that preserve KS isometries and on the backreaction of smeared anti-D3 branes. By solving the linearized IIB supergravity equations around KS, the authors classify perturbations as unsquashed or squashed and as singular or regular, linking certain modes to dilaton sources or to IASD components of $G_3$; they show that anti-D3 backreaction can induce non-ISD flux and geometry squashing, while boundary conditions in the IR fix the perturbations to match brane tensions and charges. They further compute the resulting four-dimensional gravitino mass from the fluxes, highlighting how SUSY breaking is encoded in the $(0,3)$ components and in how SUSY can be restored for special parameter choices. The work provides a controlled, perturbative framework for IR SUSY breaking in warped throats, with implications for metastable vacua, warped uplifting scenarios, and holographic gauge mediation, and outlines key open questions about interpolation to the UV and the full non-linear regime.

Abstract

We analyze properties of non-supersymmetric isometry-preserving perturbations to the infrared region of the warped deformed conifold, i.e. the Klebanov Strassler solution. We discuss both perturbations that "squash" the geometry, so that the internal space is no longer conformally Calabi-Yau, and perturbations that do not squash the geometry. Among the perturbations that we discuss is the solution that describes the linearized near-tip backreaction of a smeared collection of anti-D3-branes positioned in the deep infrared. Such a configuration is a candidate gravity dual of a non-supersymmetric state in a large-rank cascading gauge theory. Although anti-D3-branes do not directly couple to the 3-form flux, we argue that, due to the presence of the background imaginary self-dual flux, anti-D3-branes in the Klebanov-Strassler geometry necessarily produce singular non-imaginary self-dual flux. Moreover, since conformally Calabi-Yau geometries cannot be supported by non-imaginary self-dual flux, the anti-D3-branes squash the geometry as our explicit solution shows. We also briefly discuss supersymmetry-breaking perturbations at large radii and the effect of the non-supersymmetric perturbations on the gravitino mass.