  In this paper we construct the Floer homology for an action functional which
was introduced by Rabinowitz and prove a vanishing theorem. As an application,
we show that there are no displaceable exact contact embeddings of the unit
cotangent bundle of a sphere of dimension greater than three into a convex
exact symplectic manifold with vanishing first Chern class. This generalizes
Gromov's result that there are no exact Lagrangian embeddings of a sphere into
a complex vector space.
