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 ℂn.