2000- :	Professor of Physics, Institute of Physics and Astronomy, University of Aarhus, Denmark.
1991-2000:	Associate Professor (lektor), Institute of Physics and Astronomy, University of Aarhus, Denmark.
Jan. 1997:	Institut für Theoretische Physik, Innsbruck (with Prof. P. Zoller); Gastprofessor, financed by Universität Innsbruck.
Sep. 1996:	Institut d'Optique, Université Paris Sud, Orsay (with Prof. A. Aspect); Professeur Invité financed by the Academie de Versailles
1992-1993:	Max-Planck-Institut für Quantenoptik, Garching (with Prof. H. Walther); Research Fellowship financed by the Alexander-von-Humboldt Foundation.
Feb.1990-Oct.1991:	Senior Scholar, Institute of Physics, University of Aarhus.
Feb.-Jul.1989:	Laboratoire de Spectroscopie Hertzienne de l’École Normale Supérieure, Paris (with Prof. C. Cohen-Tannoudji); financed by the Danish Research Academy and the French Ministry of Education.
1986-1987:	Carlsberg Scholar.

Member of The Royal Danish Academy of Sciences and Letters, since April 2000.
Member of editorial board for the international journal Quantum Information and Computation.
Member of the Board of Directors, Aarhus University Press.