Junior Research Fellow at New College, Oxford University (1997-1998). Long-term visiting fellow at McMaster University in Hamilton, Ontario (1998). Postdoctoral fellow at the Department of Physics at Princeton University (1998 - 2001). From 2001 to 2006, he conducted research at the Laboratoire de Physique Théorique of the École Normale Supérieure in Paris and at the Centre National de la Recherche Scientifique (CNRS) as Chargé de Recherche. From 2006 to 2007 he worked at the University of Oxford in the field of theoretical physics. Director at the Max Planck Institute for the Physics of Complex Systems in Dresden since 2007 and Honorary Professor of Many-Body Physics at the Technical University of Dresden since 2008.