In this talk I will present the basic ideas on how to trap atoms and molecules using periodic potentials created by light, and how these particles can be manipulated. Using these tools, I will describe two families of experiments. In the first one, atoms are trapped and entangled into a macroscopic number of singlets. It will be shown how this state naturally evolves into a gas of atomic Cooper pairs and a Resonating Valence Bond state, depending on how the atoms move in the lattice [1]. The second and more sophisticated generation of experiments trap molecules instead of atoms. Recently we have demonstrated that, though the molecules are extremely fragile objects, a quantum phenomenon known as Zeno effect can dramatically stabilize the system, allowing us to create a Tonks-Girardeau gas of ultracold molecules[2], much like in similar experiments with atoms.
[1] "Dynamical Creation of Bosonic Cooper-Like Pairs" T. Keilmann, J.J. Garcia-Ripoll, PRL 100, 110406 (2008)
[2] "Strong Dissipation Inhibits Losses and Induces Correlations in Cold Molecular Gases" N. Syassen, D. M. Bauer, M. Lettner, T. Volz, D. Dietze, J. J. GarcÃa-Ripoll, J. I. Cirac, G. Rempe, and S. Dürr Science 6 June 2008: 1329-1331.