Working group 2: 3D gravity theories and the Kerr/CFT correspondence
Organizers: S. Detournay, G. Giribet, M. Guica, D. Persson
Date, time, and location: Tuesday 10th 17:00h, room 13-2-005
Wednesday 11th 16:00h, room 160-1-009
In the last year and a half there has been a revived interest in three-dimensional theories of gravity. The proposal by E. Witten  that 2+1 D Einstein gravity
in AdS_3 space is dual to a holomorphically factorizable theory of the class known as extremal CFT_2 has attracted considerable attention, and led to intense debate. Another model of 2+1 D gravity, Topologically Massive Gravity (TMG), corresponds to the three-dimensional Einstein gravity coupled to a gravitational Chern-Simons term without torsion . This theory contains local massive graviton degrees of freedom, and admits black hole
solutions, making TMG a very interesting model to be explored. Moreover, its holographic description in terms of a 2d CFT exhibits special properties when
the square of the Chern-Simons coupling equals the cosmological constant. The central charge of left-moving excitations in the boundary theory vanishes, leading to the still controversial suggestion that the theory might be chiral . The generalization of TMG to other backgrounds, in particular warped versions of AdS_3, has led to fabulous applications such as describing extremally rotating Kerr four-dimensional black holes .
The work-group will start with a short review about recent progress in three-dimensional gravity, with particular attention on AdS_3/CFT_2 correspondence (review of the original works [1,2], followed by a recap of the state-of-the art in TMG, and the connection with the Kerr/CFT conjecture).
Next, according to the participants' taste/interest, we'll launch an open discussion on some topics of current research interest, e.g. the chiral gravity conjecture, the Kerr/CFT correspondence for non-extremal black holes, warped backgrounds in string theory, relationship with AdS_4/CFT_3
 E. Witten, Three-dimensional gravity reconsidered, [arXiv:0706.3359]
 A. Maloney and E. Witten, Quantum gravity partition function in
 S. Deser, R. Jackiw and S. Templeton, Phys. Rev. Lett. 48 (1982) 975
 W. Li, W. Song and A. Strominger, Chiral Gravity in Three Dimensions,
JHEP04 (2008) 082, [arXiv:0801.4566].
 M. Guica, T. Hartman, W. Song and A. Strominger, The Kerr/CFT