Berlin 2001 – scientific programme

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Q: Quantenoptik

Q 9: Poster: Quantum Information

Q 9.19: Poster

Tuesday, April 3, 2001, 12:30–15:00, AT2

Light-induced decoherence in the driven evolution of an atom — •Ch. Balzer, Th. Hannemann, W. Neuhauser, P. E. Toschek, and Ch. Wunderlich — Institut für Laser-Physik, Universität Hamburg, Jungiusstr. 9, 20355 Hamburg

The hyperfine Larmor precession of an individual ground-state ¹⁷¹Yb⁺ ion has been driven by resonant rf pulses, alternated with probe pulses of 369 nm laser light that excite resonance scattering [1]. Upon varying the length of the drive pulse and averaging over 50 measurements, this rf-optical double resonance reveals hyperfine flopping (rf nutation). Weak residual resonance light present during the driving light pulse generates optical pumping from the coherently nutating ion state into the upper F=1 eigenstate, that reduces the amplitude of nutation and saturates the evolving ion in an inverted mixed state. Adjustment of the level of residual light amounts to the design of artificial decoherence, useful when studying pertubations of quantum information processing on individual ions.

[1] R. Huesmann, Ch. Balzer, Ph. Courteille, W. Neuhauser, P. E. Toschek, Phys. Rev. Lett. 82, 1611 (1999).