  The phenomenon of sonoluminescence (SL), originally observed some sixty years
ago, has recently become the focus of renewed interest, particularly with the
discovery that one can trap a single bubble and induce it to exhibit SL stably
over a large number of acoustical cycles.
  In this work we shall adopt a version of the provocative suggestion put
forward by Schwinger: the mechanism responsible for the radiation in SL is a
dynamic version of the Casimir effect. It has been known since Casimir's
original work in 1948 that the zero-point energy of quantum fields can be
modified by the presence of boundaries, and that these modifications generate
observable effects. For example, in Casimir's original work, the quantum
fluctuations of the electromagnetic field in the presence of a pair of
uncharged, parallel, perfectly conducting plates were shown to give rise to an
attractive force between the plates.
