Dynamics of evanescent matter waves in negative-index media

Semi-evanescent and evanescent matter-waves produced by an atom wave packet impinging a repulsive barrier can be back-refracted and reconstructed by the application of negative-index “comoving” potential pulses. One shows that those collapses and revivals generate a matter wave confined on both sides of the barrier border (“surface matter wave”) and should be observable via the retardation of atom reflection from the barrier interface. This property, joined to the possibility recently demonstrated of inducing negative refraction of atom waves, makes such potentials a matter-wave counterpart of negative-index materials or “meta materials” well-known in light optics.