Quantum telecloning

Quantum cryptography, quantum teleportation, and quantum computation are only a few schemes, which achieve tasks that are not possible with classical physics. These three protocols belong to a very new and at the same time rapidly progressing field called quantum information theory. In this book, we present an important application of quantum information processing: quantum telecloning. The original quantum teleportation scheme enables the transmission of an unknown state from one observer to another observer situated at a different location. We propose a generalization of this protocol called many-to-many teleportation, where the information is distributed from N senders to M receivers. The no-cloning theorem imposes that an arbitrary pure quantum state cannot be copied. By combining the many-to-many teleportation and approximate cloning, we propose the telecloning of entanglement from one pair of senders to two pairs of receivers. Further, we show how a two-output quantum processor can be built based on asymmetric telecloning of a d-level system.