Kusch, Polykarp (1911-1993), a German-born American physicist, made the first precise measurement of the magnetic properties of the electron, the negatively charged particle that forms the outer parts of all atoms. Kusch found that the electron’s magnetism differed from theoretical predictions of the time, and his work stimulated improvements in the theories of how matter and radiation interact. For this work, Kusch was awarded half of the 1955 Nobel Prize for physics. The other half was awarded to American physicist Willis Lamb (see Lamb, Willis Eugene ).
Kusch was born in Blankenburg, Germany and, in 1912, went to live in the United States with his family. He became a U.S. citizen in 1922. He studied at Case Institute of Technology (now part of Case Western Reserve University) in Cleveland, and received his Ph.D. at the University of Illinois in 1936. He taught briefly at the University of Minnesota before beginning a long teaching career at Columbia University in New York City. He remained at Columbia until 1972, when he became professor of physics at the University of Texas.
At Columbia, Kusch did the work that was to gain him his Nobel Prize, collaborating with Austrian-American physicist Isidor Rabi, already a Nobel prizewinner (see Rabi, Isidor Isaac ). Kusch measured the magnetic properties of hydrogen molecules by firing beams of them through strong magnetic fields and seeing by how much their paths were bent. From this process, he was able to calculate the magnetism of the hydrogen atom’s single electron.
At about the same time, Willis Lamb, using an entirely different method, produced a similar value for the magnetism of the electron. The new knowledge stimulated theoretical physicists to develop an improved theory of the electromagnetic interactions of matter, a subject called quantum electrodynamics.
