Casimir forces in cavities with a finite plasma frequency

Jordan Maclay

Quantum Fields LLC

Richland Center WI 53581

Carlos Villarreal

Institute de Fisica

Universidad Autonoma de Mexico

Apartado Postal 20-364

Mexico, 01000, D.F.

We extend previous calculations of the Casimir forces in perfectly conducting rectangular cavities in order to consider finite conductivity by including an exponential cutoff in the frequency. We study the renormalized stress energy tensor of the system as an explicit function of the cutoff frequency and the cavity geometry. As in the case of perfectly conducting cavities, we predict changes in the sign and magnitude of the force as the geometry of the cavity is modified. In particular, repulsive forces are predicted, even for cavities with a finite plasma frequency, but the transition from attractive to repulsive forces occurs for deeper cavities, making experiments more difficult.