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Q: Quantenoptik

Q 30: Poster: Quanteneffekte

Q 30.10: Poster

Tuesday, March 25, 2003, 16:30–18:30, Lichthof

Periodic Control of Small Quantum Networks — •Marcus Stollsteimer and Günter Mahler — Universität Stuttgart, Institut für Theoretische Physik 1, Pfaffenwaldring 57, 70550 Stuttgart

We study the Schrödinger dynamics of a system consisting of a few coupled spin-1/2 particles (qubits), which is subject to periodic external parameter control (oscillating external fields or coupling strengths). The total system can be interpreted as a system proper coupled to a finite environment or as an internally coupled quantum register, depending on the chosen partition. Without control, the coupled system usually decays into a local quasi-equilibrium (cf. PRL 54, 1879 (1985)). We try to characterize stable (quasi-stationary) non-equilibrium states induced by the periodic control. This method shows some interesting connections to the notion of decoherence-free subspaces and to refocusing schemes.