EDGE-MAGNETOPLASMON WAVE-PACKET REVIVALS IN THE QUANTUM-HALL EFFECT

The quantum-Hall effect is necessarily accompanied by low-energy excit ations localized at the edge of a two-dimensional electron system. For the case of electrons interacting via the long-range Coulomb interact ion, these excitations are edge magnetoplasmons. We address the time e volution of localized edge-magnetoplasmon wave packets. On short times the wave packets move along the edge with classical E cross B drift. We show that on longer times the wave packets can have properties simi lar to those of the Rydberg wave pickets that are produced in atoms us ing short-pulsed lasers. In particular, we show that edge-magnetoplasm on wave packets can exhibit periodic revivals in which a dispersed wav e packet reassembles into a localized one. We propose the study of edg e-magnetoplasmon wave packets as a tool to investigate dynamical prope rties of integer and Fractional quantum-Hall edges. Various scenarios are discussed for preparing the initial wave packet and for detecting it at a later time. We comment on the importance of magnetoplasmon-pho non coupling and on quantum and thermal fluctuations.