Division of Applied Mechanics
Norwegian University of Science and Technology
N-7491 Trondheim, Norway
How to calculate the lowest-frequency contribution to the Casimir
force between metallic surfaces is a delicate point. The problem
is whether the zero Matsubara frequency (m=0) contributes
to the transverse electric (TE) mode or not. By adopting the
Drude dispersive model at low frequencies we show, by means of
a limiting procedure, that the contribution from the m=0
TE mode has to be zero. Analytical work on the Casimir force
is reported, both for spherical and for planar surfaces. Numerical
results are given for planar surfaces, choosing gold as an example.
Apparent theoretical difficulties coming from negative Casimir
entropies in a restricted temperature interval are discussed.
The present paper reports work done in collaboration with J.
S. Høye, J. B. Aarseth, and K. A. Milton.