Almost BPS but still not renormalized

TL;DR

This paper demonstrates that certain non-supersymmetric 'almost-BPS' solutions exhibit a non-renormalization property similar to BPS solutions, with probe calculations matching fully back-reacted solutions, revealing insights into charge quantization.

Contribution

It shows that almost-BPS solutions share the non-renormalization property of BPS solutions, extending understanding beyond supersymmetric cases.

Findings

Probe actions reproduce full solution equations

Non-renormalization persists without supersymmetry

Clarifies charge quantization for almost-BPS solutions

Abstract

A key feature of BPS multi-center solutions is that the equations controlling the positions of these centers are not renormalized as one goes from weak to strong coupling. In particular, this means that brane probes can capture the same information as the fully back-reacted supergravity solution. We investigate this non-renormalization property for non-supersymmetric, extremal "almost-BPS" solutions at intermediate coupling when one of the centers is considered as a probe in the background created by the other centers. We find that despite the lack of supersymmetry, the probe action reproduces exactly the equations underlying the fully back-reacted solution, which indicates that these equations also do not receive quantum corrections. In the course of our investigation we uncover the relation between the charge parameters of almost-BPS supergravity solutions and their quantized charges, which solves an old puzzle about the quantization of the charges of almost-BPS solutions.