1990's Laureates
Freeman J. Dyson, 1993
Citation:
For his outstanding contributions to
fundamental scientific knowledge in fields as diverse as physics,
biology, astronomy, and mathematics; for his courageous questioning of
the risks and benefits of science and technology; and for his
wonderful articles and books that describe to the public how a
scientist looks at the world.
Biography
Professor Freeman Dyson's fundamental contributions to science
have been at the frontier of knowledge and have set, by their
originality, rigor, and relevance, a high standard of excellence. He
has helped popularize science through articles in Scientific American
and The New Yorker, and many widely acclaimed books for the general
public. In his writings, his courageous and informed challenges to
conventional approaches to science and technology have been
informative to general audiences and have been the inspiration of
generations of scientists. Professor Dyson began his research as a
mathematician before turning his interests in 1947-48 to the exciting
new developments in physics involving the theory of quantized fields.
Almost immediately upon his entry into theoretical physics, Dyson
wrote two papers on the foundations of quantum electrodynamics which
have had a profound and lasting influence on many branches of modern
theoretical physics. He proved that the equations-of-motion approach
to field theory put forth by Schwinger and Tomonaga were equivalent to
the diagrammatic rules put forth by Feynman. In doing so, he
introduced a novel approach, which has become a standard method for
deriving the Feynman rules for a given physical system. Dyson's
analysis of the renormalizability of electrodynamics has become a
classic of modern theoretical physics, appearing both in standard
textbook treatments and providing the motivation and model for much
further work on renormalizable field theories. A further important
innovation was his formulation of integral equations (now called
"Dyson's equations") which gave a nonperturbative meaning to the
Feynman-Dyson perturbation series. These equations play an important
role in the theory of many-particle systems, and find significant
application in modern formulations of the theory of superconductivity.
In the years subsequent to this work in electrodynamics, Dyson made
numerous lasting contributions to scattering theory in areas of
analytical properties of scattering amplitudes. Another of Dyson's
major interests has been statistical physics. In an important paper,
Dyson brought into tractable form a problem involving the excitation
spectra of disordered systems. In a series of papers, Dyson and Mehta
worked out a theory of the statistical behavior of energy levels of
quantum systems, and applied the theory to cases of interest in
nuclear physics. Dyson's statistical work has also involved the study
of magnetic systems and phase transitions. He developed a systematic
theory of spin wave interactions and applied it to the study of the
low temperature behavior of an ideal ferromagnet. A final and major
facet of Dyson's statistical work has been his rigorous proof with
Andrew Lenard of the stability of matter.
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