Insane Anti-Membranes?

TL;DR

This paper investigates the backreaction of anti-M2 branes on a non-AdS supergravity background with Taub-NUT asymptotics, revealing inevitable singularities that challenge previous assumptions about smearing effects.

Contribution

It provides the first analysis of anti-brane backreaction on a background with non-AdS asymptotics, showing singularities are intrinsic and not due to smearing.

Findings

Infrared singularities are unavoidable in this setup.

Singularities are not caused by brane smearing effects.

Supports the idea that singularities are inherent to anti-brane backreaction.

Abstract

The backreactions of anti-branes on a variety of supergravity backgrounds have been shown in a recent series of papers to be riled by some unexplained flux singularities. All of the situations studied so far involve backgrounds with (close to) AdS-asymptotics. It is the purpose of this work to study the backreaction of anti-M2 branes on a background exhibiting a different UV behavior: The so-called $\mathbb{A}_8$ regular solution of eleven-dimensional supergravity that we consider has "Taub-NUT type" asymptotics. As it turns out, some subleading infrared singularities are inevitable; they cannot be naturally ascribed to the anti-branes backreacting on this background. Moreover, our configuration does not involve smeared branes. This lends further credence to the work of Bena et al. suggesting that the singularities encountered are in no way remnants of smearing that would wash away once brane polarization is taken into account.