Dipole blockade in a cold Rydberg atomic sample

TL;DR

This paper reviews dipole-dipole interactions and the dipole blockade effect in cold Rydberg atoms, highlighting their potential for quantum information processing and analyzing experimental results across various configurations.

Contribution

It provides a comprehensive review of the dipole blockade phenomenon in cold Rydberg atoms, including recent experimental advances and different interaction mechanisms.

Findings

Demonstration of entanglement in atom pairs

Analysis of blockade effects in various configurations

Discussion of ion effects and plasma evolution

Abstract

We review here the studies performed about interactions in an assembly of cold Rydberg atoms. We focus more specially the review on the dipole-dipole interactions and on the effect of the dipole blockade in the laser Rydberg excitation, which offers attractive possibilities for quantum engineering. We present first the various interactions between Rydberg atoms. The laser Rydberg excitation of such an assembly is then described with the introduction of the dipole blockade phenomenon. We report recent experiments performed in this subject by starting with the case of a pair of atoms allowing the entanglement of the wave-functions of the atoms and opening a fascinating way for the realization of quantum bits and quantum gates. We consider then several works on the blockade effect in a large assembly of atoms for three different configurations: blockade through electric-field induced dipole, through F\"orster resonance and in van der Waals interaction. The properties of coherence and cooperativity are analyzed. Finally, we treat the role of dipole-dipole interactions between Rydberg atoms responsible for Penning ionization. The perturbation of the dipole blockade by ions and the evolution of the Rydberg towards an ultracold plasma are discussed.