| IBM | Almaden | San Jose | California | 1991 |
| Department of Physics | Sogang University | Seoul | South Korea | 1994 |
| Department of Physics | University of Oregon | Eugene | Oregon |
1994-95,
1996 |
Center for Advanced Studies | University of New Mexico | Albuquerque | New Mexico | 1995 |
| Institute of Physics | Chinese Academy of Sciences | Beijing | P. R. China | 1996, 2000 |
| Department of Physics | Beijing Normal University | Beijing | P. R. China | 1997 |
| Department of Physics | Technion - Israel Institute of Technology | Haifa | Israel | 1998 |
| Department of Physics | University of Toronto | Toronto | Canada | 1998 |
| Erwin Schrödinger International Institute for Mathematical Physics | Society for the International Erwin Schrödinger Institute | Vienna | Austria | 1999, 2000 |
| Edward L Ginzton Laboratory | Stanford University | Stanford | California | 2001-2003 |