Probing and controlling quantum magnetism with ultra-cold atoms

By loading spinor atoms in optical lattices it is now possible to experimentally implement quantum spin models. These systems allow the investigation of quantum magnetism ~ in strongly correlated systems within a controlled environment. In this talk we will describe a novel approach~to prepare, detect and control super-exchange interactions in ultra-cold~spinor atoms in optical superlattices [1]. Recently this approach was used for the first experimental realization of super-exchange interactions in ultra-cold atoms [2]. The many-body dynamics arising from the coherent coupling between singlet-triplet pairs in adjacent double-wells will be also discussed. ~In particular, we will describe how it can lead to the formation of frustrated spin states with a high degree of multi-particle entanglement. Finally, we will present an extension of this approach to prepare and detect d-wave pairing in an array of coupled plaquettes. \newline ~[1] A. M. Rey, V. Gritsev,I. Bloch, E. Demler, and M. D. Lukin, PRL 99, 140601 (2007). \newline ~[2] S. Trotzky, P. Cheinet, S. Folling, M. Feld, U. Schnorrberger, A.M. Rey, A. Polkovnikov, E. Demler, M. D. Lukin, and I. Bloch., submitted for publication.