New Near Extremal Black Holes and Love Symmetry

TL;DR

This paper introduces a new class of near-extremal black holes in (2,2) signature with integrable structures and exact Love symmetry, revealing insights into their near-horizon geometry and perturbation spectra.

Contribution

It presents a novel near-extremal black hole solution with exact integrable and Love symmetry structures in (2,2) signature, expanding understanding of black hole symmetries and geometries.

Findings

Black holes exhibit an integrable $SL(2,\mathbb{R})\times SL(2,\mathbb{R})$ structure.

The near-horizon region is described by the Eguchi-Hanson instanton.

Normalizable spectrum yields quasinormal modes in Lorentzian signature.

Abstract

Rotating and charged black holes are known to exhibit remarkable properties close to extremality, including emergent hidden symmetries and holographic duality to 2D theories. In this note, we introduce a new class of near-extremal black holes living in $(2,2)$ signature, strongly resembling the Lorentzian ones but with an exact integrable structure $SL(2,\mathbb{R})\times SL(2,\mathbb{R})$. The exterior of the black hole is a self-dual solution with a photon ring. It develops an infinite near-horizon throat described by the Eguchi-Hanson instanton. An exact version of the so-called Love symmetry controls perturbations on the throat. Furthermore, the normalizable spectrum of this black hole provides quasinormal modes in Lorentzian signature.