Rotating Circular Strings, and Infinite Non-Uniqueness of Black Rings

TL;DR

This paper introduces new five-dimensional solutions describing rotating black rings with dipole fields, revealing an infinite non-uniqueness of black ring configurations and connecting them to string theory microstates.

Contribution

It presents novel self-gravitating rotating black ring solutions with dipole charges, demonstrating infinite non-uniqueness and linking to string theory microstates.

Findings

Existence of infinite black ring solutions with same mass and angular momentum.

Reproduction of Bekenstein-Hawking entropy microscopically for extremal rings.

Connection of solutions to intersecting branes and four-charge black holes.

Abstract

We present new self-gravitating solutions in five dimensions that describe circular strings, i.e., rings, electrically coupled to a two-form potential (as e.g., fundamental strings do), or to a dual magnetic one-form. The rings are prevented from collapsing by rotation, and they create a field analogous to a dipole, with no net charge measured at infinity. They can have a regular horizon, and we show that this implies the existence of an infinite number of black rings, labeled by a continuous parameter, with the same mass and angular momentum as neutral black rings and black holes. We also discuss the solution for a rotating loop of fundamental string. We show how more general rings arise from intersections of branes with a regular horizon (even at extremality), closely related to the configurations that yield the four-dimensional black hole with four charges. We reproduce the Bekenstein-Hawking entropy of a large extremal ring through a microscopic calculation. Finally, we discuss some qualitative ideas for a microscopic understanding of neutral and dipole black rings.