REPULSIVE CASIMIR FORCE, REALIZABLE OR NOT?

Casimir energies and forces have been calculated in various configurations and boundary conditions. The calculations indicated that the Casimir energy might change its sign depending not only on the boundary conditions but also on geometry and topology of the configuration. With the development of nanotechnology, it is known that repulsive Casimir force is very important in nanodevices. In this paper, we review some research results on repulsive Casimir force, and discuss whether it could be realizable theoretically and experimentally.