Universality versus material dependence of fluctuation forces between metallic wires

We calculate the Casimir interaction between two parallel wires and between a wire and a metal plate. The dielectric properties of the objects are described by the plasma, Drude, and perfect metal models. We find that at asymptotically large separation interactions involving plasma, wires and/or plates are independent of the material properties but depend on the dc conductivity sigma for Drude wires. Counterintuitively, at intermediate separations the interaction involving Drude wires can become independent of sigma. At smaller separations, we compute the interaction numerically and observe an approach to the proximity approximation.