Casimir force and complications in the van Kampen theory for dissipative systems

In dissipative media it appears as if there are distinct normal modes with complex valued energies. The summation of the zero-point energies of these modes render a complex valued result. Using the contour integration, resulting from the use of the generalized argument principle, gives a real valued and different result. This paper resolves this contradiction and shows that the true normal modes form a continuum with real frequencies. Furthermore, it suggests a way to obtain an approximate result from a summation of the zero-point energy of modes