Since 2006: Professor (W3) for Mathematics (Global Analysis and Differential Geometry), Universität Hamburg, Germany
2002–2005: Professor, Institut Élie Cartan de Mathématiques, Université Henri Poincaré - Nancy I, France
2000–2002: Lecturer (C2), Mathematisches Institut, Universität Bonn, Germany
1999–2000: Stand-In Professor (C3), Mathematisches Institut, Universität Freiburg i. Br., Germany
1999: Habilitation, Mathematik, Universität Bonn, Germany
1996–1999: Assistant (C1), Mathematisches Institut, Universität Bonn, Germany
1995–1996: Humboldt Fellow at the Mathematical Sciences Research Institute in Berkeley, USA
1994–1995: Postdoc, Mathematisches Institut, Universität Bonn, Germany
1994, Doctorate in Mathematics, Universität Bonn, Germany, supervisor: Werner Ballmann
1987–1988: Licence Mathématiques, Paris 7, France, Paris
1985–1986 and 1988–1992: Degree in Mathematics, Universität Bonn, Germany

2022–2023: Member of the Steering Committee of the Cluster of Excellence Quantum Universe, Universität Hamburg, Germany
Head of the examination board and coordinator of the MSc program Mathematics, Department of Mathematics, Universität Hamburg, Germany
Head of the Department of Mathematics, Universität Hamburg, Germany
Head of the PhD examination board, Department of Mathematics, Universität Hamburg, Germany
Since 2014: Editor of the “Beiträge zur Algebra und Geometrie”
Since 2013: Editor of “Differential Geometry and its Applications”
Since 2006: Managing Editor of the “Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg”