"Spatially ordered structures and coherent control in a two-dimensional Rydberg gas"

"Rydberg atoms provide a way to achieve controlled long-range interactions in many-body systems. In our setup we implemented an optical detection technique for Rydberg atoms with sub-micron resolution, which allows for the measurement spatial correlations in strongly interacting collective states of Rydberg atoms. We prepare a two-dimensional system of ground state atoms in an optical lattice and laser couple them to a Rydberg state. The Rydberg atoms interact via the van der Waals force, which extends over approximately half the system size, thereby leading to strong correlations. Guided by numerical optimization we found laser sweeps that created self-organized many-body states with spatially ordered Rydberg excitations. The initial ground state atom configuration is crucial for the success of the sweeps. We developed a preparation technique based on local addressing in an optical lattice that allows for the preparation of sub-shot-noise initial atom numbers. The developed techniques might allow for the deterministic preparation of ordered fock states of Rydberg atoms and the investigation of their coherence properties."