Rydberg dressing: understanding of collective many-body effects and implications for experiments

Abstract

The strong interaction between Rydberg atoms can be used to control the\nstrength and character of the interatomic interaction in ultracold gases by\nweakly dressing the atoms with a Rydberg state. Elaborate theoretical proposals\nfor the realization of various complex phases and applications in quantum\nsimulation exist. Also a simple model has been already developed that describes\nthe basic idea of Rydberg dressing in a two-atom basis. However, an\nexperimental realization has been elusive so far. We present a model describing\nthe ground state of a Bose-Einstein condensate dressed with a Rydberg level\nbased on the Rydberg blockade. This approach provides an intuitive\nunderstanding of the transition from pure twobody interaction to a regime of\ncollective interactions. Furthermore it enables us to calculate the deformation\nof a three-dimensional sample under realistic experimental conditions in\nmean-field approximation. We compare full three-dimensional numerical\ncalculations of the ground state to an analytic expression obtained within\nThomas-Fermi approximation. Finally we discuss limitations and problems arising\nin an experimental realization of Rydberg dressing based on our experimental\nresults. Our work enables the reader to straight forwardly estimate the\nexperimental feasibility of Rydberg dressing in realistic three-dimensional\natomic samples.\n