MECHANICAL RESPONSE OF VACUUM

A path integral formulation is developed for the dynamic Casimir effec t. It allows us to study arbitrary deformations in space and time of t he perfectly reflecting (conducting) boundaries of a cavity. The mecha nical response of the intervening vacuum is calculated to linear order in the frequency-wave-vector plane. For a single corrugated plate we find a correction to mass at low frequencies, and an effective shear v iscosity at high frequencies, both anisotropic. For two plates there i s resonant dissipation for all frequencies greater than the lowest opt ical mode of the cavity.