The Prize Committee for Physics has unanimously decided that the Wolf Prize for 1981 should be equally divided among:
Freeman J. Dyson
Institute for Advanced Study
Princeton, New Jersey, U.S.A.
Gerard īT Hooft
University of Utrecht
Utrecht, The Netherlands
Victor J. Weisskopf
Massachusetts Institute of Technology
Cambridge, Massachusetts, U.S.A.
for their outstanding contributions to theoretical physics, especially in the development and application of the quantum theory of, fields.
Professor Freeman J. Dyson is noted for major contributions to many different areas of physics and technology in which he has made effective use of his deep knowledge of mathematics. In early work, he showed that the apparently different approaches of Tomonaga, Schwinger and Feynman to quantum electrodynamics were internally consistent and led to the same results. Shortly after he proved that divergences of the theory would be removed in every order of perturbation theory by incorporating them in the renormalized charge and mass of electron. In these works, Dyson developed an elegant mathematical method, based on the V-matrix, which has become basic to more general field theories as well as to the many-body problem, of the physics of condensed matter.
In classic work with A. Lenard, he proved the stability of matter that the attractive force between electrons and the positive nuclei does not cause matter to collapse. In another area, on the analyticity of scattering amplitudes, he obtained results fundamental to dispersion theory methods for scattering problems. His wide-ranging interests extend from biology to astrophysics, including such technological areas as nuclear reactors and solar energy. Through his writings, he has contributed greatly to the public understanding of science.
Professor Gerard `T Hooft has made a major contribution to the revival of quantum field theory as an essential part of our understanding of elementary particle interactions. Following earlier work by his thesis advisor, M. Veltman, in 1971 `T Hooft showed that infinities could be eliminated by renormalization in theories with spontaneously broken gauge symmetries, such as the electroweak theory of Weinberg and Salam. Together with Veltman, he then systematically developed the mathematical background for calculations in such theories, including especially the method of dimensional regularization, which has been of great value in many areas; including even quantum gravity. `T Hooft also showed how dimensional regularization could serve as the basis for renormalization group calculations, by the so-called 'minimum substraction' technique. He then went on to do ground breaking work on a number of topics. He laid the foundation for systematic calculations of instanton effects, including the striking effect of baryon nonconservation. He revived interest in magnetic monopoles by showing that these particles are necessary consequences of a wide variety of gauge theories. He initiated a new approach to the calculation of physical quantities in gauge theories of strong interactions, by the 'large N' approximation. Most recently, he has developed methods for deciding what sorts of, massless bound states may be expected to occur in various gauge theories, providing a mathematical basis for speculations about composite particle models of quarks and leptons. A large part of the theoretical physics of the 1970īs has been based on the seminal papers of `T Hooft.
The activity of Professor Victor F. Weisskopf extends over a period of more than 50 years and covers two subfields of theoretical physics: quantum field theory and theoretical nuclear physics. Furthermore, he has gained a reputation as an international statesman In quantum field theory his main contributions are (1) An early recognition that the incorporation of the positron in quantum electrodynamics eased to a large extent the self-energy difficulties and that infinities might be removed by renormalization of the electronīs mass and charge. (2) In collaboration with Pauli he formulated the correct quantization method for boson fields and gave the proper method for extending to bosons the concept of antiparticles. These chievements make him one of the pioneers of quantum field theory.
In nuclear physics he successfully applied thermodynamical methods to Bohrs compound nucleus model obtaining many semiquantitative results that guided the art for years. Furthermore, he analyzed with H. Feshbach and C. Porter neutron nucleus scattering. Introducing statistical methods, founded on quantum mechanics, that have been successfully applied in several different contexts even outside of the nuclear field.
As Director of CERN and on many other occasions he has shown considerable diplomatic ability addressed to improve international relations in science, fostering, to quote the statute of the Wolf Foundation, humanity and brotherly relationships amongst the peoples.