University, USA 1 month in 2019 and 1 month in 2024 at GSI Previous 2024 Michael Wiescher, Department of Physics, University of Notre Dame, USA 3 months from February to April 2024 at GSI 1 month extension [...] Dalian University of Technology, China 1.5 months from September 15 to October 31, 2024, at U Heidelberg Kenji Fukushima, Department of Physics, Tokyo University, Japan 1 month in October 2024 at U Heidelberg [...] Tokyo Institute of Technology, Japan 1 month from May 9 to June 9, 2024, at TU Darmstadt 2023 Davide Proment, School of Mathematics, University of East Anglia, U.K. 1.5 months in 2023 and 2024 at U Heidelberg