Physicist, experimental and theoretical (Quantum theory of metals, superconductivity, and particle and nuclear physics). Major affiliations include: Institut for Teoretisk Fysik, Copenhagen, Denmark, 1931-1932; Institut Henri Poincar,̌ Paris, France, 1933-1934; and Stanford University, Stanford, CA, USA, 1934-1941, 1945-. He died in 1983.