Ben Mottelson 1926-2022

We are very sad to learn that our beloved colleague and friend, Ben Mottelson, passed away on May 13.

Ben was of enormous importance for the Niels Bohr Institute, as well as Nordita (the Nordic Institute for Theoretical Physics), where he was employed for most of his career. With Aage Bohr he developed a unified model of atomic nuclei that could explain the many facets of the properties of nuclei. This model combined aspects of Niels Bohr's liquid drop model with shell effects, and for this work Ben, together with Aage Bohr and James Rainwater, was awarded the Nobel Prize in Physics in 1975.

Ben had a strong influence on his contemporaries in the field, as well as the younger generation of physicists in nuclear and quantum many-body physics. In later years, he turned his attention to metallic clusters, quantum dots and ultracold atomic gases, and also worked with Aage Bohr and Ole Ulfbeck on the foundations of quantum physics.