  For mechanical Weber gravitational wave antennae, it is thought that gravity
waves are weakly converted into acoustic vibrations. Acoustic vibrations in
metals (such as Aluminum) are experimentally known to be attenuated by the
creation of electron-hole pairs described via the electronic viscosity. These
final state electronic excitations give rise to gravitational wave absorption
cross sections which are considerably larger (by four orders of magnitude) than
those in previous theories which have not explicitly considered electronic
excitations.
