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SYCP: Symposium Strongly coupled plasmas

SYCP 1: Symposium Strongly Coupled Plasmas

SYCP 1.3: Hauptvortrag

Dienstag, 20. März 2007, 15:00–15:30, 5D

At the frontier of cold Rydberg gases and ultracold plasmas — •Pierre Pillet — Laboratoire Aimé Cotton, CNRS, Bât.505, Campus d'Orsay, 91405 Orsay cedex, France

Cold Rydberg atomic samples are fascinating because they are at the frontier of atomic, solid state and plasma physics. A first example is the limitation of the Rydberg excitation due to long-range dipole-dipole interactions between Rydberg atoms with the so-called dipole blockade effect observed by adding an electric field or at a Förster resonance. An exciting possible application is the realization of scalable quantum gates. A second example is given by a dense ensemble of cold Rydberg atoms which can evolve towards an ultracold plasma. The mechanism of the formation of the ultracold plasma will be discussed. It is complex, first initiated by different ionization elementary processes. In this first phase, the dipole forces between Rydberg atoms play a role for Penning ionization. When the ionic space charge becomes important enough to trap the electrons, these electrons ionize then rapidly all the Rydberg atoms in an avalanche process, leading to the formation of a quasi-neutral plasma. Different processes as superelastic collisions, electronic recombinations need to be considered in this second phase for a complete understanding. To reach the regime where the Coulomb interctions between the plasma particules become important compared to their kinetic energy will lead to strong spatial correlations up to the crystallization. Cooling such an ultracold plasma is therefore an important challenge. The idea of adding Rydberg atoms to an ultracold plasma to control its electronic temperature has been investigated.