As a part of a research collaboration with the group of Dr. Axel Pelster, SCL's Antun Balaz has visited Free University of Berlin from 15 to 27 February 2009. In addition to the continuous support by the research project OI141035 of the Serbian Ministry of Science and EU Centre of Excellence Grant CX-CMCS, this collaboration is now also supported through the bilateral Serbian-German project PI-BEC, which is jointly co-funded by the Serbian Ministry of Science and the German DAAD foundation for the period 2009-2010.

The visit has focused on the ongoing work on applying the earlier developed discretized effective actions to the calculation of global and local properties of fast-rotating ideal Bose-Einstein condensates, as well as on how to efficiently include the interactions to the model. On 24 February 2009 A. Balaz gave a talk entitled "Ultra-fast Converging Path Integral Approach for Ideal Bose Gases", reviewing the method and presenting preliminary numerical results obtained so far. The talk initiated useful discussions with Dr. Hagen Kleinert and other members of FU Berlin physics department. The new obtained results will be also presented at the forthcoming DPG Spring Meeting in March 2009 in Dresden, Germany.

Several discussions during the visit centered around possibilities for numerical studies of ultra-cold quantum gases with disorder. Further visits of German scientists to Serbia and vice versa were also considered.