| Alireza Qaiumzadeh , Center for Quantum Spintronics-Norwegian University of Science and Technology, Trondhein, Norway, June 11 - July 4, 2019 |
| Leili Javidpour , IPM, School of Physics, Tehran, Iran, May 22 - Aug. 6, 2019 |
| Shinji Mukohyama , Yukawa Institute for Theoretical Physics (YITP), Kyoto University, Kyoto, Japan, Jan. 18-25, 2019 |
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