Hannover 2003 – wissenschaftliches Programm

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Q: Quantenoptik

Q 28: Poster: Quanteninformation

Q 28.13: Poster

Dienstag, 25. März 2003, 16:30–18:30, Lichthof

Geometric quantum-gate operations without dynamical phases using stimulated Raman adiabatic passage (STIRAP) — •R. G. Unanyan, M. Fleischhauer, and K. Bergmann — Fachbereich Physik der Universität Kaiserslautern, 67653 Kaiserslautern, Germany

We propose a scheme for quantum computation based only on geometric adiabatic manipulations. Recently Jones et. al [1] demonstrated an implementation of a conditional geometric phase gate based on nuclear magnetic resonance and using spin echo to cancel the dynamical phase. In order to achieve an evolution that does not depend on specific interaction parameters i.e. on a dynamical phase, we use as the state vector a nulleigenvalue adiabatic state. Evolution of such a state has no dynamical phase. For the implementation we propose an extension of 3-level STIRAP to a tripod-linkage system as used in [2]. Recently Duan et.al [3] employed this idea for geometric quantum computation. Their two-qubit operation, however, requires the change of the relative phase of laser fields in a cyclic way. We here propose a more general scheme that avoids control of all external phases. It is illustrated for the case of two interacting spin-1 particles but can be applied to any pairs of dipole-interacting three level atoms.

[1] J. A. Jones, et al, Nature, 403, 869 (1999).

[2] H.Theuer, et al, Optics Express, 4, 77 (1999).

[3] L.-M. Duan, J. I. Cirac, P. Zoller, Science 292, 1695 (2001).