Even-dimensional topological gravity from Chern-Simons gravity

It is shown that the topological action for gravity in 2n-dimensions can be obtained from the (2n + 1)-dimensional Chern-Simons gravity genuinely invariant under the Poincare group. The 2n-dimensional topological gravity is described by the dynamics of the boundary of a (2n + 1)-dimensional Chern-Simons gravity theory with suitable boundary conditions. The field phi(a), which is necessary to construct this type of topological gravity in even dimensions, is identified with the coset field associated with the non-linear realizations of the Poincare group ISO(d - 1.1). (C) 2009 Elsevier B.V. All rights reserved.