Institution: | a Institut für Theoretische Physik, TU Braunschweig, Mendelssohnstr. 3, Braunschweig, D-38106, Germany b Department of Problems of Physics and Energetics, Moscow Institute of Physics and Technology, Russia c Dialogue Science-Computing Center Russian Academy of Science, Vavilova St. 40, GSP-1, 117967 Moscow, Russia |