Physical Consequences of a Theory with Dynamical Volume Element

Abstract

We survey motivation, basic ideas and physical consequences of a theory where the underlying action involves terms both with the usual volume element $\sqrt{-g}d^{4}x$ and with the new one $\Phi d^{4}x={4!}d\varphi_{1}\wedge d\varphi_{2}\wedge d\varphi_{3}\wedge d\varphi_{4}$. The latter may be interpreted as the 4-form determined on the 4-D space-time manifold (not necessary Riemannian). Regarding the scalar fields $\varphi_{a} (a=1,...4)$ as new dynamical variables and proceeding in the first order formalism we realize the so-called Two Measures Theory which possesses a number of attractive features. We discuss new physical effects which arise from this theory and in particular strong gravity effect in high energy physics experiments.