title: Kibble-Zurek Mechanism in the Self-Organization of a Cold Atomic Cloud.
abstract: When applying two counterpropagating laser beams to a cold cloud of rubidium atoms, we observe the spontaneous formation of intensity patterns associated with a spatial structuration of the atomic spins. We study the average number of defects in these patterns as a function of the sweep time employed to cross the instability threshold. We observe a power-law decrease of the number of defects with increasing sweep time, typical of the Kibble-Zurek mechanism. The measured exponent is consistent with the prediction for a supercritical bifurcation.
authors.affiliation: Université Côte d'Azur, CNRS, INLN, 06560 Valbonne, France.
authors.forename: G
authors.initials: G
authors.lastname: Labeyrie
authors.affiliation: Université Côte d'Azur, CNRS, INLN, 06560 Valbonne, France.
authors.forename: R
authors.initials: R
authors.lastname: Kaiser