Valentine Bargmann

Valentine "Valya" Bargmann (April 6, 1908 – July 20, 1989) was a German-American mathematician and theoretical physicist.

Biography 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.