Anisotropic blockade using pendular long-range Rydberg molecules

Ultralong-range "butterfly" Rydberg molecules possess large dipole moments which lead to long-range anisotropic interactions between molecules. Their properties are studied using a Hamiltonian that fully includes the electronic and nuclear spin degrees of freedom. Using this more accurate and complete theoretical description, we investigate the intermolecular interaction when the molecules are prepared in pendular states. The anisotropy of this interaction manifests itself strongly in the density of created molecules. (paper)