Interactions destroy dynamical localization with strong and weak chaos

¹ Max-Planck-Institut für Physik komplexer Systeme - Nöthnitzer Straß e 38, D-01187 Dresden, Germany, EU
² Vinča Institute of Nuclear Sciences - P.O. Box 522, 11001 Belgrade, Serbia

^a goran@pks.mpg.de

Received: 10 August 2011
Accepted: 20 September 2011

Abstract

Bose-Einstein condensates loaded into kicked optical lattices can be treated as quantum kicked-rotor systems. Noninteracting rotors show dynamical localization in momentum space. The experimentally tunable condensate interaction is included in a qualitative Gross-Pitaevskii–type model based on two-body interactions. We observe strong- and weak-chaos regimes of wave packet spreading in momentum space. In the intermediate strong-chaos regime the condensate energy grows as t^1/2. In the asymptotic weak-chaos case the growth crosses over into a t^1/3 law. The results do not depend on the details of the kicking.