O-BTZ: Orientifolded BTZ Black Hole

TL;DR

This paper introduces a new class of AdS3 black hole solutions called O-BTZ, which involve orientifolding by a Z_2 symmetry, expanding the known set of un-oriented AdS3 black holes beyond the traditional BTZ solutions.

Contribution

The paper constructs and characterizes O-BTZ solutions, a novel class of un-oriented AdS3 black holes obtained through orientifolding by a Z_2 symmetry in the isometry group.

Findings

O-BTZ solutions encompass all un-oriented AdS3 black holes.

O-BTZ geometries are stationary and axisymmetric with two asymptotic charges.

They differ from BTZ black holes by involving orientation-changing orbifolding.

Abstract

Banados-Teitelboim-Zanelli (BTZ) black holes are constructed by orbifolding AdS3 geometry by boost transformations of its O(2,2) isometry group. Here we construct a new class of solutions to AdS3 Einstein gravity, orientifolded BTZ or O-BTZ for short, which in general, besides the usual BTZ orbifolding, involve orbifolding (orientifolding) by a Z_2 part of O(2,2) isometry group. This Z_2 is chosen such that it changes the orientation on AdS3 while keeping the orientation on its 2D conformal boundary. O-BTZ solutions exhaust all un-oriented AdS3 black hole solutions, as BTZ black holes constitute all oriented AdS3 black holes. O-BTZ, similarly to BTZ black holes, are stationary, axisymmetric asymptotically AdS3 geometries with two asymptotic charges, mass and angular momentum..