A note on wavemap-tensor cosmologies

Abstract

We examine theories of gravity which include finitely many coupled scalar fields with arbitrary couplings to the curvature (wavemaps). We show that the most general scalar-tensor $\sigma$-model action is conformally equivalent to general relativity with a minimally coupled wavemap with a particular target metric. Inflation on the source manifold is then shown to occur in a novel way due to the combined effect of arbitrary curvature couplings and wavemap self-interactions. A new interpretation of the conformal equivalence theorem proved for such `wavemap-tensor' theories through brane-bulk dynamics is also discussed.Comment: 8 pages, LaTeX, to appear in the Proceedings of the 2nd Hellenic Cosmology Workshop, National Observatory of Athens, April 21-22, 2001, (Kluwer 2001