Heidelberg 2015 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 49: Quantum Effects: Cavity QED I
Q 49.1: Group Report
Thursday, March 26, 2015, 11:00–11:30, B/gHS
Cooperative Coupling and Cooling of Individual Atoms in an Optical Cavity — R. Reimann1, W. Alt1, T. Kampschulte2, T. Macha1, N. Thau1, S. Yoon1, •L. Ratschbacher1, and D. Meschede1 — 1Institut für Angewandte Physik der Universität Bonn — 2Departement Physik, Universität Basel
Optical cavities are excellent tools to strongly enhance the otherwise weak coupling of photons to individual trapped atoms. In the context of quantum communication they can act as efficient light-matter interfaces, which are essential elements for transferring quantum information between matter qubits and photonic qubits. The cooperative coupling of small ensembles of neutral atoms to photons can be used to increase the bandwidth of these interfaces.
Here, we investigate several of the challenges that arise for cooperative interaction: Residual atomic motion of trapped atoms complicates the ideal cavity QED situation of point-like, spatial fixed atoms with constant coupling strength. To reduce its detrimental effects, we have implemented a novel intra-cavity Raman sideband cooling scheme. The method is enhanced by a complete suppression of excitations on the two-photon carrier transition.
To study cooperative interaction effects we have implemented the controlled coupling of two atoms to the cavity mode. We observe constructive and destructive photon emission depending of the relative atomic positions. Our results are important for the realization of phase-sensitive cQED protocols, such as collective the photon storage in small atomic ensembles or the cavity mediated entanglement of two atoms.