Casimir force between left-handed-material slabs

The Casimir effect between two left-handed-material (LHM) slabs is investigated. For the LHM described by dispersive permittivity and permeability of Drude-Lorentz type, the structure of dispersion curve over negative refraction frequency band is determined by material characteristic frequencies. The bandwidth of the negative refraction characterizes the reflection property, and thus influences the Casimir effect between the slabs. Furthermore, a comparison of the Casimir forces for LHM and ordinary dielectric slabs, which have the opposite values of refractive indices at the chosen frequency, is shown. Generally, the force for LHM with sufficiently large bandwidth of negative refraction is greater than the force for ordinary dielectrics.