Aktuelles Physik-Kolloquium:

27. Apr. 2017, 16:00 Uhr, Gebäude NW1, Raum H3

Kommunikation und Rechnen mit Quanten: vom no-Cloning Theorem zum Quantenrepeater

Prof. Dr. Peter van Look, Johannes-Gutenberg-Univ. Mainz

The impossibility for creating more copies from one given copy of an arbitrary quantum mechanical state is known as the so-called no-cloning theorem published in 1982. It may be considered one of the first formal results expressed in the language of quantum information theory. Starting with this little, innocently looking theorem, I will give an overview of various notions and applications of quantum information and communication including entanglement, quantum teleportation, quantum error correction, and quantum measurements. Besides the ultimate application of a quantum computer, I shall focus on the possibility of quantum communication over large intercontinental distances by means of a quantum repeater. A recent trend in quantum repeater research aims to circumvent the need for quantum storage and light-matter interfaces entirely. I will present examples for this class of memoryless repeaters that can, in principle, achieve rates as obtainable in classical communication. These repeaters are based on optical quantum error correction codes adapted to photon loss errors and they may be operated in an all-optical fashion.