Eugene P. Wigner was born into a well-to-do family in
Budapest 100 years ago. .He attended the Fasori Lutheran
Gymnasium, which educated - among others - John von Neumann,
and John Harsanyi,Nobel-laureate in economics. Wigner was
influenced by his math teacher, László Rátz who taught
calculus in high school. World War I, revolutions and
counter/revolutions, kingdom, republic, soviet type council
republic followed each other in dizzying sequence, so Wigner
decided to continue his university studies in Berlin, where
quantum mechanics was discussed and developed in the 1920s.
After his Ph.D. Wigner worked in Budapest and in Berlin, and
he elaborated the foundations of quantum mechanics based on
symmetry principles. He wrote his book on symmetries during
a summer holiday in Hungary, and this later brought him the
Nobel Prize. Wigner moved to the U.S. in 1930, where he
enjoyed the excellent working conditions and recognition. He
revisited his homeland only in the 1970s, where his ideas
about the future attracted huge audiences at the Academy of
Sciences, at universities, and in the Physical Society. He
received high honors from his home country - a bit
belatedly. The principal focus of his attention was the
quantum-mechanical concept of measurement, the role of human
consciousness. But even in his last years, in the 1980s, he
most enjoyed his visits to high schools - attending physics
classes, discussing the future of science in human society
with teachers and students.
[I3.002] Eugene Wigner, The First Nuclear Reactor Engineer
Alvin M. Weinberg (Oak Ridge National Laboratory)
All physicists recognize Eugene Wigner as a theoretical physicist of the very first rank. Yet Wigner's only advanced degree was in Chemical Engineering. His physics was largely self-taught.
During WWII, Wigner brilliantly returned to his original
occupation as an engineer. He led the small team of
theoretical physicists and engineers who designed, in
remarkable detail, the original graphite-moderated,
water-cooled Hanford reactor, which produced the Pu239 of
the Trinity and Nagasaki bombs. With his unparalleled
understanding of chain reactors (matched only by Fermi) and
his skill and liking for engineering, Wigner can properly be
called the Founder of Nuclear Engineering. The evidence for
this is demonstrated by a summary of his 37 Patents on
various chain reacting systems.
[I3.003] Wigner's Changing View of the Elementary Quantum Phenomenon
John Archibald Wheeler (Princeton University and University of Texas at Austin)
In 1961, Eugene Wigner argued that "the being with a consciousness must have a different role in quantum mechanics than the inanimate measuring device." By 1981, he had changed to a totally different position, one compatible with the position of Niels Bohr, that all it requires for the elementary quantum phenomenon is an elementary process brought to a close by an irreversible act of amplification (i.e. the click of a counter or the blackening of a grain of photographic emulsion.) It is instructive to review the reasons Wigner gives for this important change in his views.
[I3.004] Eugene Wigner and Symmetries In Physics
Marcos Moshinsky (Instituto de Fisica-UNAM. Apartado Postal 20-364, 01000 Mexico, DF MEXICO)
Concepts of symmetry in physics have had a long history, particularly if they are of a geometric or crystallographic origin, yet in classical physics they had a somewhat esoteric position. This situation changed radically when in the XX Century we passed from classical to quantum mechanics. In the former a state for a system of particles was given by a number of points in phase space and the transformation groups related with symmetries mainly gave the invariance of concepts such as energy or angular momentum. In the latter the state is characterized by a vector in Hilbert space in which the transformations had a representation. Eugene Wigner was the right man (for his mathematical ability and physical intuition) at the right place and time (Germany, in the twenties) to take full advantage of this new situation. His first interest was atomic spectroscopy (then a very active field) and the fact that its basic states were related with irreducible representation of the orthogonal group in three dimensions O(3). The German version of his book on ``Group theory and Application" published in 1931 established, as he quotes ``that almost all rules of spectroscopy follow from the symmetry of the problem". His later extension to the direct product of two or more representations led to his development of the 3-j symbol, that he explicitly derived, and his interest in the properties of 6-j, 9-j, etc. His awareness of the time inversion as an antiunitary operator, and the analysis of its combination with the unitary representations of other symmetries, proved fundamental for deriving the features of time reversed reactions from their direct behavior. His interest in space reflection and the concept of parity led to important selection rules, and was of relevance even in weak interactions where parity is not a good symmetry.
His later interest in nuclear physics, solid state, elementary particles etc., was almost never without a component of the role of symmetry in these problems. The best example of this is his work on the ``Unitary representations of the inhomogeneous Lorentz group" (1939) which led later to the possible form of equations and interactions in the elementary particle field.
Eugene Wigner was certainly one of the giants of XX Century physics and his contribution not only influenced the field in his time but is also likely to be fundamental in the century that will follow the centennial we are celebrating now.