title: Optimal quantum cloning via stimulated emission
abstract: We show that optimal universal quantum cloning can be realized via stimulated emission. Universality of the cloning procedure is achieved by choosing systems that have appropriate symmetries. We first discuss a scheme based on stimulated emission in certain three-level systems, e.g., atoms in a cavity. Then we present a way of realizing optimal universal cloning based on stimulated parametric down-conversion. This scheme also implements the optimal universal NOT operation.
authors.affiliation: Institut fur Experimentalphysik, Universitat Wien, Boltzmanngasse 5, A-1090 Wien, Austria.
authors.initials: C
authors.lastname: Simon
authors.initials: G
authors.lastname: Weihs
authors.initials: A
authors.lastname: Zeilinger