Dresden 2011 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 5: Ultracold Atoms: Manipulation and Detection
Q 5.2: Talk
Monday, March 14, 2011, 10:45–11:00, SCH 251
Feedback control of the hyperfine ground states of neutral atoms in an optical cavity — •Stefan Brakhane1, Wolfgang Alt1, Miguel Martinez-Dorantes1, Tobias Kampschulte1, René Reimann1, Artur Widera1,2, and Dieter Meschede1 — 1Institut für Angewandte Physik der Universität Bonn, Wegelerstr. 8, 53115 Bonn — 2Fachbereich Physik der TU Kaiserslautern, Erwin-Schrödinger-Str., 67663 Kaiserslautern
Detection and manipulation of atomic spin states is essential for many experimental realizations of quantum gates. Feedback schemes to stabilize the states and their superpositions can counteract perturbations caused by the environment.
In our experiment we deduce the atomic spin state of one or two Caesium atoms by measuring the transmission of a probe laser through a high-finesse cavity. Depending on the number of atoms in the hyperfine state that strongly couples to the cavity, the resonance of the cavity is shifted and the probe laser transmission is decreased. We employ a Bayesian update formalism to obtain time-dependent probabilities for the atomic states of one and two atoms [1].
I will present an experimental implementation using a digital signal processor which allows us to determine the atomic spin state in real-time.
First experimental results of an extension to a feedback loop for the preparation and stabilization of atomic states will be shown.
S. Reick, K. Mølmer et al., J. Opt. Soc. Am. B 27, A152 (2010)