In preparation for release from the Soviet Union, it was standard practice to put personnel into quarantine for a few years if they worked on projects related to the Soviet atomic bomb project, which Rexer did. After quarantine, he was sent to the Deutsche Demokratische Republik (DDR, German Democratic Republic) in 1956. He was appointed extraordinarius professor and Director of the Institutes für die Anwendung radioaktiver Isotope (Institute for the Application of Radioactive Isotopes) at the Technische Hochschule Dresden (today, Technische Universität Dresden). Other notable German scientists, who worked on the Soviet atomic bomb project and joined Rexer at the Technische Hochschule Dresden were Heinz Pose and two other physicists, Werner Hartmann and Heinz Barwich, who had been at Gustav Hertz's Institute G, in Agudseri (Agudzery).Ernst Rexer – Technische Hochschule Dresden.
