Gottfried Jens Feder
Jens Feder, Professor Emeritus of Physics at the University of Oslo, Norway, died from pancreatic cancer on 15 February 2019, two weeks after celebrating his 80th birthday. He was born in Munich, Germany, on 31 January 1939, a son of physician Hans Georg Feder and Lajla Stolz. He moved with his mother to Oslo in 1947. In 1965 he married Liv Elisabeth Sverdrup, and he is survived by her and their two children, Heidi and Hans Jakob.
Jens had broad research interests, including condensed matter physics, fluid dynamics, complex systems, and geophysics, and he used theoretical, experimental, and numerical methods to achieve important advances in these areas. Today he is best known for his work on fractals and their scientific and industrial applications. His beautiful monograph, Fractals (Plenum, 1988), has achieved a wide readership in English and has been translated to Russian, Japanese, and Chinese. He also produced seminal works on biophysics (with Ivar Giaever), nucleation theory, dynamics of phase transitions, avalanche dynamics, flow in porous media, and random sequential adsorption. Jens had a very collaborative research style, and many of his papers were coauthored with international colleagues from the US, Israel, Switzerland, France, and other countries.
One of his most important early contributions, the classic paper “Homogeneous nucleation and growth of droplets in vapours ,” was a product of his collaboration with his thesis advisor, Jens Lothe. Following his graduation, Jens received a NATO fellowship to study phase transitions and superconductors with Pierre-Gilles de Gennes’ group in Orsay, France (1965–66). Jens then joined IBM Zürich Research in Switzerland (1966–68), where he worked on phase transitions in perovskites with Alex Müller and Heini Rohrer.
In 1970 Jens was awarded the Doctor Philosophiae degree from the University of Oslo, based primarily on a thesis titled “A study of hysteresis in the phase transition of superconductors and antiferromagnets.” In 1968 he became a lecturer in physics at the University of Oslo, and in 1974 he was appointed to the position of full professor of physics. During his tenure in Oslo, Jens spent sabbaticals at the IBM T.J. Watson Research Center in Yorktown Heights, New York (1972–73), at General Electric Corporate Research in Schenectady, New York (1978–79), as the Williams Otis Crosby lecturer of Geology at MIT (1997), at the Isaac Newton Institute for Mathematical Sciences in Cambridge, UK, and at Imperial College London (1999).
Jens started a new research direction at the University of Oslo when, in 1972, he joined forces with his good friend and colleague Torstein Jøssang to establish the Cooperative Phenomena Group (CPG). Light-scattering studies of protein aggregation by this group led to the interest in fractals that dominated the last 40 years of Jens’s research career. The group’s accomplishments became widely recognized in the 1980s, and the experimental, theoretical, and numerical modeling research that followed, together with industrial collaborations facilitated by their company, Fracton Inc, formed the foundations for one of Norway’s first centers of excellence, the center for the Physics of Geological Processes (2003–13). In PGP, Jens and geologist Bjørn Jamtveit formed the basis for a new, internationally recognized discipline at the intersection between physics and geoscience. Among the many honors Jens received was election as a Member of the Norwegian Academy of Science and Letters in 1988 and as a Fellow of the American Physical Society in 1989.
During his career, Jens mentored a large number of developing researchers. Over 50 graduate students and numerous postdocs from many countries received support through the CPG and PGP and performed research under his guidance. His rigorous supervision and wide interests and knowledge gave his apprentices a solid foundation for leading careers in academia, independent research laboratories, industry, and government agencies in Norway and abroad.
Outside of physics, Jens had a passion for sailing and carpentry. He and Liv spent many happy summer months sailing in the Baltic Sea and along the Norwegian Coast, and they enjoyed taking visitors from all over the world on short sailing trips in the Oslo Fjord.
Jens will be deeply missed by all of us who had the privilege of working or studying with him. The loss of his knowledge, creativity, and ability to see connections between traditionally separate fields will be widely felt among physicists and other scientists worldwide.
