Berlin 2001 – scientific programme

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Q: Quantenoptik

Q 15: Quantum Information IV

Q 15.6: Talk

Tuesday, April 3, 2001, 18:45–19:00, H 3010

Suppression of arbitrary internal coupling in a quantum register — •Marcus Stollsteimer and Günter Mahler — Universität Stuttgart, Institut für Theoretische Physik 1, Pfaffenwaldring 57, 70550 Stuttgart

For the implementation of a quantum computer it is necessary to be able to exercise complete control over the internal Hamiltonian of the used physical system. For NMR quantum computing the effectively acting Hamiltonian can be controlled by pulse sequences. We examine a register consisting of N selectively addressable spins with pairwise coupling between each spin pair. By application of a pulse train the time evolution can be influenced. We show that complete decoupling of the spins is possible independent of the particular form of the spin-spin interaction. The proposed method is efficient in the sense that the effort regarding time and amount of pulses increases only polynomially with the size N of the register. We also regard the effect of external control errors in terms of inaccurate control pulses.