Finite-temperature Casimir force between metal plates: full inclusion of spatial dispersion resolves a long-standing controversy

I show that inclusion of spatial dispersion has very small effects on the zero-temperature Casimir force between metal plates, but has dramatic effects at finite temperatures. At high temperatures and/or at large separations, the force is reduced by a factor of 2 compared to the classical perfect-metal result. This is obtained irrespective of if dissipation is included or not. The Nernst heat theorem is not violated even for defectless metal crystals.