Seminars of the Focus Area Complex Systems

Prof. Dr. C. Beta, Prof. Dr. K. Dethloff, Prof. Dr. R. Engbert, Prof. Dr. M. Holschneider, Prof. Dr. W. Huisinga, Prof. Dr. Ralf Metzler, Prof. Dr. A. Pikovsky, Prof. Dr. S. Reich, Prof. Dr. M. Rosenblum, Prof. Dr. G. Rüdiger, Prof. Dr. T. Scheffer, Prof. Dr. F. Scherbaum, Prof. Dr. J. Selbig, Prof. Dr. F. Spahn

Seminar

Speaker: V.S. Bagnato, Institute de Fisica de Sao Carlos - University of S. Paulo,, Sao Carlos - SP - Brazil

Title: Emergence of turbulence in Bose-Einstein condensate

Time: Wed Nov 4, 2009, 5:15pm

Place: Building 28, Room 0.108

Abstract:
Besides the already existent variety of techniques to generate vortices, new techniques can always provide new and exciting ways to explore this topic. In this work we present a new technique to nucleate vortices in a BEC, where an oscillating field generated by a set of coils is superimposed to the trapping field creating displacement, rotation and deformation of the trap potential. As a function of the amplitude of oscillation of the external magnetic field we observe several different behaviors of the condensate cloud allowing the construction of a diagram for stable structures. For small amplitudes the condensate oscillates its axis in a banding mode. Increasing the amplitude we observe the formation of one, two, three or more vortices in the cloud. Above certain amplitude of oscillation we observe uncountable vortices in every direction , producing a tangled vortices configuration which can be considered as the emergence of a turbulent regime in the cloud. At the same time, in a few special configurations, a three vortices/anti-vortices cluster seems to be observed. Variations of behavior during TOF for the cloud may be a signature of the turbulent regime. Finally in extremes conditions of oscillations, a fragmentation of the cloud is observed. Analysis involving the fragmentation of the quantum atomic fluid due to the presence of oscillations is presented through an analogy involving time oscillation and random spatial field is presented.

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Past NLD Seminars (1994-2007) & (2008 ...)

Students' seminar: Theoretical Physics, PIK, Modeling & TSA Berlin-Potsdam-Colloquia: PhysGesellschaft Berlin, TU Berlin, Pro Physik, AIP, AEI, MPI-KGF, GFZ, HMI, PIK, AWI, Max Planck Institute for the History of Science, Mathematik, DPG Disputationen, & Vorschau UP

Udo Schwarz, Zentrum für Dynamik komplexer Systeme,
Universität Potsdam, Campus Golm Karl-Liebknecht-Str. 24, 14476 Potsdam, building 28, room 2.107
Phone: (+49-331) 977-1658, Fax : (+49-331) 977-1045

Email: Udo.Schwarz AT uni-potsdam.de

DFG SFB 1294

DFG Sonderforschungsbereich 1294 Data assimilation

DFG SPP 1488

DFG Schwerpunktprogramm 1488 Planetmag


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