A note on wavemap-tensor cosmologies

TL;DR

This paper explores scalar-tensor wavemap theories of gravity, revealing their conformal equivalence to general relativity with a minimally coupled wavemap, and discusses novel inflation mechanisms and brane-bulk interpretations.

Contribution

It demonstrates the conformal equivalence of general scalar-tensor wavemap theories to Einstein gravity with a specific target metric, and introduces new inflationary insights.

Findings

Scalar-tensor wavemap theories are conformally equivalent to Einstein gravity with a minimally coupled wavemap.

Inflation can occur due to combined effects of curvature couplings and wavemap interactions.

A new interpretation of conformal equivalence via brane-bulk dynamics is proposed.

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.