Collective excitation and emission phenomena in a strongly interacting ultracold gas

Atoms excited to high lying g quantum states, so-called Rydberg atoms, are highly polarizable and, therefore interact strongly with each other at large distances. One result of these interactions is the Rydberg dipole blockade effect, in which strongly interacting atoms excited by the same driving pulse may prevent other atoms from getting excited. This blockade offers several applications, for example the realization of quantum logic gates [1] and the possibility of creating entangled states with two atoms [2].