PROBLEMS IN THEORY OF THE CASIMIR EFFECT

The Casimir effect manifests itself as a force acting between two un-charged macrobodies in vacuum. It originates from the existence of zero-point and thermal fluctuations of the electromagnetic field. During the last few years the Lifshitz theory describing the Casimir force between bodies made of real materials faces contradictions with basic principles of thermodynamics and with the experimental data. We review basic theoretical and experimental problems arising in this connection.