  We derive an effective two-dimensional low-energy theory for thin
superconducting films coupled to a three-dimensional fluctuating
electromagnetic field. Using this theory we discuss plasma oscil- lations,
interactions between charges and vortices and extract the energy of a vortex.
Having found that the effective theory properly describes the long distance
physics, we then use it to investigate to what extent the superconducting film
is a topologically ordered phase of matter.
