BTZ black hole

The BTZ black hole, named after Maximo Banados, Claudio Teitelboim, and Jorge Zanelli, is a black hole solution for (2+1)-dimensional gravity with a negative cosmological constant.

When the cosmological constant is zero, a vacuum solution of (2+1)-dimensional gravity is necessarily flat, and it can be shown that no black hole solutions exist. It therefore came as a surprise when black hole solutions were shown to exist for a negative cosmological constant.

The BTZ black hole is remarkably similar to the (3+1)-dimensional black hole. Like the Kerr black hole it contains an inner and an outer horizon.It has "no hairs" (No hair theorem) and is fully characterized by ADM-mass, angular momentum and charge. It also possesses thermodynamical properties analogous to the (3+1)-dimensional black hole. E.g. its entropy is captured by a law directly analogous to the Bekenstein bound in (3+1)-dimensions, essentially with the surface area replaced by the BTZ black holes circumference.

Since (2+1)-dimensional gravity has no Newtonian limit, one might fear that the BTZ black hole is not the final state of a gravitational collapse. It was however shown, that this black hole does arise from collapsing matter.

The BTZ solution is often discussed in the realm on (2+1)-dimensional quantum gravity.

References

* The original BTZ-paper http://arxiv.org/abs/hep-th/9204099
* A review by S.Carlip on BTZ balck holes and related topics http://arxiv.org/abs/gr-qc/0503022
* An older review by S.Carlip solely on BTZ balck holes http://arxiv.org/abs/gr-qc/9506079v1
* A review by one of the inventors Banados http://arxiv.org/abs/hep-th/9901148v3