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Q: Quantenoptik und Photonik
Q 75: Poster Quanteninformation
Q 75.3: Poster
Thursday, March 16, 2006, 16:30–18:30, Labsaal
Completely positive covariant maps for qubits and the U-NOT — •Jaroslav Novotny1, Gernot Alber2, and Igor Jex1 — 1FJFI CVUT v Praze, CZ-115 19 Praha 1, Czech Republic — 2Institut für Angewandte Physik, TU Darmstadt, D-64289, Darmstadt
We investigate characteristic properties of completely positive covariant quantum processes involving one and two qubits. In particular, we analyze how the complete positivity and linearity of quantum processes constrains various operations of special interest for quantum information processing. As particular examples we consider the U-NOT operation acting on arbitrary pure single qubit states and on entangled pure two-qubit states of a given degree of entanglement. The influence of the degree of entanglement on the optimally achievable fidelities is worked out.