Heidelberg 2015 – scientific programme

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A: Fachverband Atomphysik

A 36: Poster: Ultra-cold plasmas and Rydberg systems (with Q)

A 36.7: Poster

Thursday, March 26, 2015, 17:00–19:00, C/Foyer

Long-range Rydberg molecules – Rydberg-Rydberg and Rydberg–ground-state interactions — •Johannes Deiglmayr, Heiner Saßmannshausen, and Frédéric Merkt — Laboratory of Physical Chemistry, ETH Zürich, Switzerland

We report on two recent observations in our experiments with ultracold Cs atoms [1]. First, we discuss the observation of dipole-quadrupole interactions between two Rydberg atoms. Because the dipole-quadrupole interaction does not conserve the electronic parity, the conservation of total parity requires that the excitation of dipole-quadrupole-coupled pair states in our experiments [2] is accompanied by an entanglement of electronic and rotational motions of the atom pair, which is facilitated by the near-degeneracy of even- and odd-L partial waves.

Second, we report on the experimental characterization of singlet-scattering channels in long-range Rydberg molecules composed of a Rydberg and a ground-state atom. We observe the formation of such molecules by photoassociation spectroscopy near np_3/2 resonances (n=26-34). The spectra reveal two types of molecular states recently predicted by Anderson et al. [PRL 112, 163201 (2014)]: Deeply bound pure triplet states and more weakly bound states with mixed singlet and triplet character. The experimental observations are well described by a model including s-wave scattering, the hyperfine interaction of the ground-state atom and the fine-structure of the Rydberg atom.

[1] H. Saßmannshausen, F. Merkt, J. Deiglmayr, PRA 87, 032519 (2013); [2] J. Deiglmayr, H. Saßmannshausen, P. Pillet, and F. Merkt, PRL 113, 193001 (2014)