Perturbative and Non-perturbative N =8 Supergravity

TL;DR

This paper investigates extremal black holes in N=8 supergravity, revealing that BPS states become massless only at the moduli space boundary and analyzing the nature of singularities and their implications for UV finiteness.

Contribution

It provides a detailed analysis of black hole solutions, singularities, and the behavior of BPS states in N=8 supergravity, highlighting differences from lower N theories and discussing UV finiteness implications.

Findings

BPS states become massless only at the boundary of moduli space.

Stringy states exhibit null singularities in four-dimensional space-time.

Standard singularity resolution methods do not work in D=4, N=8 supergravity.

Abstract

We study extremal black holes, their ADM mass and area of the horizon in N = 8 supergravity. Contrary to intuition gained from N = 2, 4 theories, in N = 8 supergravity BPS states may become massless only at the boundary of moduli space. We show that stringy states described in [1], which have no mass gap and survive in the toroidal compactification in addition to massless states of perturbative N = 8 supergravity, display a null singularity in four-dimensional space-time, when viewed as solutions of N = 8 Einstein equations. We analyze known methods of resolving such singularities and explain why they do not work in D=4, N = 8 supergravity. We discuss possible implications for the issue of UV finiteness of the four-dimensional N = 8 perturbation theory.