| 1948-49 | Fellow, Harvard University |
| 1950-51 | Fellow, Massachusetts Institute of Technology |
| 1951-54 | Staff Member, Laboratory for Insulation Research |
| 1954-56 | Assistant Professor, Syracuse University |
| 1956-60 | Associate Professor, Brandeis University |
| 1960-61 | NSF Postdoctoral Fellow, CERN, Geneva |
| 1961- | Professor of Physics, Brandeis University |
| 1963-64 | Fulbright, University of Rome, Italy, Spring Term |
1969-70 | Visiting Professor, Massachusetts
Institute of Technology |
| 1976 | Edward and Gertrude Swartz Professor of
Theoretical Physics | |
| 1977-79 | Chairman, Department of Physics |