Warped flatland
Stéphane Detournay (Physique Mathématique des Interactions Fondamentales, Université Libre de Bruxelles, and International Solvay Institutes, Campus Plaine – CP 231, Bruxelles, 1050, Belgium); Wout Merbis (Physique Mathématique des Interactions Fondamentales, Université Libre de Bruxelles, and International Solvay Institutes, Campus Plaine – CP 231, Bruxelles, 1050, Belgium); Gim Ng (Hamilton Mathematical Institute, Trinity College Dublin, Dublin 2, Ireland, School of Mathematics, Trinity College Dublin, Dublin 2, Ireland); Raphaela Wutte (Institute for Theoretical Physics, TU Wien, Wiedner Hauptstr. 8-10/136, Vienna, A-1040, Austria)
We study warped flat geometries in three-dimensional topologically massive gravity. They are quotients of global warped flat spacetime, whose isometries are given by the 2-dimensional centrally extended Poincaré algebra. The latter can be obtained as a certain scaling limit of Warped AdS3 space with a positive cosmological constant. We discuss the causal structure of the resulting spacetimes using projection diagrams. We study their charges and thermodynamics, together with asymptotic Killing vectors preserving a consistent set of boundary conditions including them. The asymptotic symmetry group is given by a Warped CFT algebra, with a vanishing current level. A generalization of the derivation of the Warped CFT Cardy formula applies in this case, reproducing the entropy of the warped flat cosmological spacetimes.