Heidelberg 2015 – scientific programme
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A: Fachverband Atomphysik
A 42: Ultracold Plasmas and Rydberg Systems III (with Q)
A 42.1: Talk
Friday, March 27, 2015, 11:00–11:15, P/H2
Coherent manipulation of a superatom — •Johannes Zeiher1, Peter Schauß1, Sebastian Hild1, Jae-yoon Choi1, Tommaso Macri1,2, Immanuel Bloch1,3, and Christian Groß1 — 1Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching, Germany — 2QSTAR, Largo Enrico Fermi 2, 50125 Firenze, Italy — 3Fakultät für Physik, Ludwig-Maximilians-Universität München, Schellingstraße 4, 80799 München, Germany
Rydberg atoms offer the possibility to engineer long range interacting systems of ultracold atoms due to their strong van der Waals interactions. This can be harnessed to generate entangled states of many particles, which are of interest for metrology and quantum information applications. In our experiment, we start from a 2d Mott insulator of ground state atoms of rubidium-87. Using our recently developed single site addressing technique, we spatially control their shape and prepare samples with sub-shot noise atom number fluctuations. We optically excite Rydberg atoms and detect them in our optical lattice with submicron resolution. When the interaction energy becomes larger than the optical coupling bandwidth, the system is fully Rydberg blockaded and described as an effective two-level system, frequently called “superatom”. We confirm the predicted collective √N scaling of the optical coupling with the number of atoms from a single up to 180 particles. Furthermore, we demonstrate coherent manipulation of the superatom by performing Ramsey spectroscopy. We explore physics beyond the superatom description by detecting doubly excited states when the system size is on the order of the blockade radius.