Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electromagnetic eigenmodes in matter. van der Waals-London and Casimir
  forces   We derive van der Waals-London and Casimir forces by calculating the
eigenmodes of the electromagnetic field interacting with two semi-infinite
bodies (two halves of space) with parallel surfaces separated by distance d. We
adopt simple models for metals and dielectrics, well-known in the elementary
theory of dispersion. In the non-retarded (Coulomb) limit we get a d^{-3}-force
(van der Waals-London force), arising from the zero-point energy (vacuum
fluctuations) of the surface plasmon modes. When retardation is included we
obtain a d^{-4}-(Casimir) force, arising from the zero-point energy of the
surface plasmon-polariton modes (evanescent modes) for metals, and from
propagating (polaritonic) modes for identical dielectrics. The same Casimir
force is also obtained for "fixed surfaces" boundary conditions, irrespective
of the pair of bodies. The approach is based on the equation of motion of the
polarization and the electromagnetic potentials, which lead to coupled integral
equations. These equations are solved, and their relevant eigenfrequencies
branches are identified.

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The categories of this paper are: nucl-th
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-fin
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The categories of this paper are: q-alg
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The categories of this paper are: q-bio
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The categories of this paper are: bayes-an
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The categories of this paper are: econ
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The categories of this paper are: physics
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The categories of this paper are: adap-org
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The categories of this paper are: eess
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The categories of this paper are: math
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The categories of this paper are: stat
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The categories of this paper are: hep-lat
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The categories of this paper are: patt-sol
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The categories of this paper are: nlin