Lower bound for angular momenta of microstate geometries in five dimensions

TL;DR

This paper establishes lower bounds on the angular momenta of five-dimensional microstate geometries with few centers, revealing conditions under which they mimic maximally spinning black holes and exploring their topological features.

Contribution

It provides the first analysis of angular momentum bounds for microstate geometries with at least five centers in five-dimensional supergravity.

Findings

Angular momenta have lower bounds slightly below BMPV black hole values.

Existence of a narrow parameter region where microstates match BMPV angular momenta.

Topological structure of evanescent ergosurfaces depends on magnetic fluxes.

Abstract

We study the BPS solutions of the asymptotically flat, stationary microstate geometries with bi-axisymmetry and reflection symmetry in the five-dimensional ungauged minimal supergravity. We show that the angular momenta of the microstate geometry with a small number of centers (at least, five centers) have lower bounds, which are slightly smaller than those of the maximally spinning BMPV black hole. Therefore, there exists a certain narrow parameter region such that the microstate geometry with a small number of centers admits the same angular momenta as the BMPV black hole. Moreover, we investigate the dependence of the topological structure of the evanescent ergosurfaces on the magnetic fluxes through the 2-circles between two centers.