München 2004 – wissenschaftliches Programm

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Q: Quantenoptik und Photonik

Q 7: Quantenkommunikation

Q 7.9: Vortrag

Montag, 22. März 2004, 18:30–18:45, HS 101

Quantum Cellular Automata and the Capacity of Quantum Channels with Memory — •Dennis Kretschmann, Dirk Schlingemann, and Reinhard F. Werner — Institut für Mathematische Physik, Technische Universität Braunschweig, Mendelssohnstr. 3, 38106 Braunschweig, Germany

Any processing of quantum information, be it storage or transfer, can be represented by a quantum channel. Quantum channel capacity expresses quantitatively how much quantum information can be stored in a physical device, or sent down a transmission line: it is the maximal number of qubit transmissions per use of the channel, taken in the limit of long messages.

Up to now most of the work on quantum channels has focused on memoryless channels, which are characterized by the requirement that successive channel inputs are acted on independently. In many real-world settings this assumption cannot be justified. In this talk we show how to describe and characterize quantum channels with memory, emphasizing and exploiting connections with the theory of quantum cellular automata and the physics of spin chains.