title: Equality of the energy and group velocities of bulk acoustic waves in piezoelectric media.
abstract: The equality of the energy and group velocities of bulk acoustic waves in a lossless piezoelectric medium is demonstrated, with the energy velocity defined from the generalized energy density and the generalized Poynting vector.
authors.forename: Vincent
authors.initials: V
authors.lastname: Laude
authors.forename: Alexandre
authors.initials: A
authors.lastname: Reinhardt
authors.forename: Abdelkrim
authors.initials: A
authors.lastname: Khelif