We study the influence of Casimir energy on the critical field of a
superconducting film, and we show that by this means it might be possible to
directly measure, for the first time, the variation of Casimir energy that
accompanies the superconducting transition. It is shown that this novel
approach may also help clarifying the long-standing controversy on the
contribution of TE zero modes to the Casimir energy in real materials.Comment: 12 pages, 5 figures. Talk given at 7th Workshop on Quantum Field
Theory Under the Influence of External Conditions (QFEXT 05), Barcelona,
Catalonia, Spain, 5-9 Sep 200