From Quantum Puzzles to Quantum Information Technology
02/09/2005 09:00 | Durée 00:52:30

Intervenants : Anton Zeilinger , Institute of Experimental Physics, University of Vienna and IQOQI (Institute of Quantum Optics and Quantum Information), Austrian Academy of Sciences - Austria .  

The conceptual challenges raised by quantum physics have given rise to a number of experiments on individual quantum particles which have now reached an advanced experimental stage. Experiments with entangled photons not only confirm the nonlocality of Nature, they have recently given rise to new concepts in quantum information. Of these, quantum teleportation and quantum cryptography have left the shielded environment of the laboratory and are now feasible over distances of many kilometers. In the future, such experiments might even involve photon sources on satellites. The most recent concept of oneway quantum computation realized with entangled photons implements a completely new paradigm where the information, instead of proceeding via operations on some input state, is actually performed through successive measurements on a sufficiently complex entangled state. The technological realization of future quantum computation systems hinges on the question whether decoherence can be overcome. Detailed studies with macromolecules indicate that decoherence might not be as severe as often feared.