  We study a single-electron pulse injected into the chiral edge-state of a
quantum Hall device and subject to a capacitive Coulomb interaction. We find
that the scattered multi-particle state remains unentangled and hence can be
created itself by a suitable classical voltage-pulse $V(t)$. The application of
the inverse pulse $-V(-t)$ corrects for the shake-up due to the interaction and
resurrects the original injected wave packet. We suggest an experiment with an
asymmetric Mach-Zehnder interferometer where the application of such pulses
manifests itself in an improved visibility.
