Lamek Hulthén

Professor at the Royal Institute of Technology (KTH) 1949-1976.

His chair, originally called 'Applied Mathematics II', from 1954 'Mathematical Physics', became the foundation of the Department of Theoretical Physics at KTH, and he was its first chairman 1964-76.

Lamek Hulthén was a member of the Royal Swedish Academy of Sciences (KVA) and of the Swedish Academy of Engineering Sciences (IVA). He was on the Nobel committee for Physics 1966-79, being its chairman from 1975, and editor in chief of Physica Scripta from its foundation in 1970.

He served on the board of Nordita, as a delegate to CERN and ESRO, on government committees on physics, nuclear, space, and traffic safety research, and as a consultant to defence agencies on operational analysis and nuclear physics.

Lamek Hulthén's scientific work dealt with several aspects of quantum physics. The first published work [Über die quantenmechanische Herleitung der Balmerterme, 1933] was the first application of the O(4) symmetry to study the hydrogen atom bound state spectrum. O(4) was used implicitly in the infinitesimal form with two sets of angular momentum type generators. The doctoral dissertation [Über das Austauschproblem eines Kristalles, 1938] was in solid state physics. Inspired by H.A. Kramers it continued work by Heisenberg and Bethe on magnetic properties of crystals, concentrating on the problem of antiferromagnetism.
After the thesis Hulthén turned to the then new subject of meson field theory, aimed primarily at the derivation of the nucleon-nucleon potential. During the 40's and 50's Hulthén, with various coworkers, studied the two-nucleon problem, both for the bound state (the deuteron) and the scattering states. In this connection he made what was probably his most original contribution to theoretical physics, namely a variational method for treating scattering problems (Hulthén's variational principle). A variant of Hulthén's method was introduced later (1948) by W. Kohn, and it is since then sometimes termed the Hulthén-Kohn variational principle. In connection with the two-nucleon problem Hulthén introduced an approximation to the Yukawa potential which allows for a closed solution in the two-nucleon S state; this is now called the Hulthén potential. The status of the two-nucleon problem was presented in an article in Handbuch der Physik with M. Sugawara ("The Two-Nucleon Problem", Vol 39, pp 1-143, 1957).

These notes on Lamek Hulthén's scientific work were contributed by Bengt Nagel.