It is with great sadness that we learnt of the passing of Lars Brink on 29 October 2022 at the age of 78. Lars Brink was an emeritus professor at Chalmers University Göteborg, Sweden and a member of the Royal Swedish Academy. He started his career as a fellow in the CERN theory group (1971–1973), which was followed by a stay at Caltech as a scientific associate (1976–1977). In subsequent years he was a frequent visitor at CERN, Caltech and ITP Santa Barbara, before becoming a full professor of theoretical physics at Chalmers in 1986, which under his guidance became an internationally leading centre for string theory and supersymmetric field theories.
Lars held numerous other appointments, in particular as a member and chairperson on the board of NORDITA, the International Center for Fundamental Physics in Moscow, and later as the chairperson of the advisory board of the Solvay Foundation in Brussels. Since 2004 he was an external scientific member of the Max Planck Institute for Gravitational Physics in Golm. During his numerous travels Lars was welcomed by many leading institutions all over the world. He also engaged in many types of community service, such as the coordination of the European Union network “Superstring Theory” since 2000. Most importantly, he served on the Nobel Committee for physics many years, and as its chairperson for the 2013 Nobel Prize in Physics awarded to François Englert and Peter Higgs.
Lars was a world-class theoretical physicist, with many pioneering contributions, especially to the development of supergravity and superstring theory, as well as many other topics. One of his earliest contributions was a beautiful derivation of the critical dimension of the bosonic string (with Holger Bech Nielsen), obtained by evaluating the formally divergent sum over zero-point energies of the infinitely many string oscillators; this derivation is now considered a standard textbook result. In 1976, with Paolo Di Vecchia and Paul Howe, he presented the first construction of the locally supersymmetric world-sheet Lagrangian for superstrings (also derived by Stanley Deser and Bruno Zumino) which now serves as the basis for the quantisation of the superstring and higher loop calculations in the Polyakov approach. His seminal 1977 work with Joel Scherk and John Schwarz on the construction of maximal (N = 4) supersymmetric Yang–Mills theory in four dimensions laid the very foundation for key developments of modern string theory and the AdS/CFT correspondence that came to dominate string-theory research only much later. Independently of Stanley Mandelstam, he proved the UV finiteness of the N = 4 theory in the light-cone gauge in 1983, together with Olof Lindgren and Bengt Nilsson – another groundbreaking result. Equally influential is his work with Michael Green and John Schwarz on deriving supergravity theories as limits of string amplitudes. More recently, he devoted much effort to a reformulation of N = 8 supergravity in light-cone super-space (with Sudarshan Ananth and Pierre Ramond). His last project before his death was a reevaluation and pedagogical presentation of Yoichiro Nambu’s seminal early papers (with Ramond).
Lars received numerous honours during his long career. In spite of these achievements he remained a kind, modest and most approachable person. Among our many fondly remembered encounters we especially recall his visit to Potsdam in August 2013, when he revived an old tradition by inviting the Nobel Committee to a special retreat for its final deliberations. The concluding discussions of the committee thus took place in Einstein’s summer house in Caputh. Of course, we were all curious for any hints from the predictably tight-lipped Swedes in advance of the official Nobel announcement, but in the end the only useful information we got out of Lars was that the committee had crossed the street for lunch to eat mushroom soup in a local restaurant!
He leaves behind his wife Åsa, and their daughters Jenny and Maria with their families, to whom we express our sincere condolences. We will remember Lars Brink as a paragon of scientific humility and honesty, and we miss a great friend and human being.