Stimulated parametric down-conversion and quantum cloning

Sergey A. Podoshvedov, Jaewoo Noh, Kisik Kim

Jan Peřina, J. Křepelka

Christoph Simon, Gregor Weihs, Anton Zeilinger

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.

Sadegh Raeisi, Wolfgang Tittel, Christoph Simon

Tanita Permaul, Andrew Forbes, Thomas Konrad

We present a quantum optical formulation of difference-frequency generation (DFG) that incorporates the spatial modes of light. It reproduces the well-established result for classical light beams and establishes the relation of DFG to stimulated and spontaneous parametric down-conversion. As shown here, these relations determine that stimulated parametric down-conversion can realize N → M d -dimensional optimal quantum cloning.

Z. Y. Ou