Born in Berlin,
Germany, to a
German Jewish family, Bargmann studied there from 1925 to 1933. After the National Socialist
Machtergreifung, he moved to Switzerland to the
University of Zürich where he received his Ph.D. under
Gregor Wentzel. He emigrated to the U.S., barely managing immigration acceptance, as his German passport was to be revoked with only two days of validity left. At the
Institute for Advanced Study in
Princeton (1937–1946) he worked as an assistant to
Albert Einstein, publishing with him and
Peter Bergmann on classical five-dimensional
Kaluza–Klein theory (1941). He taught at
Princeton University from 1946 for the rest of his career. He pioneered understanding of the
irreducible unitary representations of SL2(R) and the
Lorentz group (1947). He further formulated the
Bargmann–Wigner equations with
Eugene Wigner (1948), for particles of arbitrary spin, building up on work of several theorists who pioneered
quantum mechanics.
Bargmann's theorem (1954) on projective unitary representations of
Lie groups gives a condition for when a projective unitary representation of a Lie group comes from an ordinary unitary representation of its universal cover. Bargmann further discovered the
Bargmann–Michel–Telegdi equation (1959) describing relativistic precession;
Bargmann's limit of the maximum number of QM bound states of a potential (1952); the notion of
Bargmann potentials for the radial Schrödinger equations with bound states but no non-trivial scattering, which play a basic role in the theory of
Solitons, and the holomorphic representation in the
Segal–Bargmann space (1961), including the
Bargmann kernel. Bargmann was elected a Fellow of the
American Academy of Arts and Sciences in 1968. In 1978, he received the
Wigner Medal, together with Wigner himself, in the founding year of the prize. In 1979, Bargmann was elected to the US
National Academy of Sciences. In 1988, he received the
Max Planck Medal of the
German Physical Society. He was also a talented pianist. He died in
Princeton in 1989. ==References==