We show that topological 3D gravity with torsion can be formulated as a Chern-Simons gauge theory, provided a specific parameter, known as the effective cosmological constant, is negative. In that case, the boundary dynamics of the theory corresponding to anti-de Sitter boundary conditions is described by a conformal field theory with two different central charges.
@article{arxiv.gr-qc/0307078,
title = {3D gravity with torsion as a Chern-Simons gauge theory},
author = {M. Blagojevic and M. Vasilic},
journal= {arXiv preprint arXiv:gr-qc/0307078},
year = {2009}
}