Casimir Effect for Gauge Fields in Spaces with Negative Constant   Curvature
  We consider gauge theories based on abelian $p-$forms on real compact hyperbolic spaces. Using the zeta-function regularization method and the trace tensor kernel formula, we determine explicitly an expression for the vacuum energy (Casimir energy) corresponding to skew-symmetric tensor fields. It is shown that the topological component of the Casimir energy for co-exact forms on even-dimensional spaces, associated with the trivial character, is always negative. We infer on the possible cosmological consequences of this result. 
A. A. Bytsenko (DF/Uel), M. E. X. Guimaraes (MAT/Unb) and V. S. Mendes   (DF/Uel)