Physical restrictions on the Casimir interaction of metal-dielectric metamaterials: An effective-medium approach

摘要

Using an effective-medium approach, we demonstrate that the Casimir interaction of structured metal-dielectric metamaterial slabs which effectively behave as either uniform nongyrotropic materials or bi-isotropic materials is attractive at all distances, independent of the emergence of artificial magnetism or strong magnetoelectric coupling, when the slabs stand in a vacuum. In particular, it is shown that the magnetic response of a metaldielectric metamaterial is always diamagnetic at imaginary frequencies, and this explains in simple physical terms the impossibility of Casimir repulsion.