Düsseldorf 2007 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 34: Poster Quanteninformation

Q 34.1: Poster

Tuesday, March 20, 2007, 16:30–18:30, Poster C

True Quantum Dephasing of 2 Qubits — •Julius Helm and Walter Strunz — Theoretical Quantum Dynamics, Institute of Physics, University of Freiburg, Hermann-Herder-Strasse 3, 79104 Freiburg, Germany

A thorough understanding of dephasing processes is of fundamental importance in quantum information. It is known that for a single qubit general dephasing may always be described by random unitary dynamics (so-called random external field (REF)-channels), yet this seizes to be true for two or more qubits [1]. Our aim is to investigate differences between REF-dephasing channels and dephasing originating from entanglement with an environment. As a toy model we consider a system of two qubits that are independently coupled to an "environment" consisting of another qubit.

[1] L. J. Landau and R. F. Streater, Lin. Alg. Appl. 193: 107-127 (1993)