Chapter One: 1893-1986
This historical sketch was written by Hellmut Fritzsche when he was Chairman of the Department in 1986. A second chapter has been written by Professor Thomas Witten.
The Physics Department got off to a flying start in 1893 when A. A. Michelson, the most outstanding American scientist of the time, came to Chicago. He saw to the appointment of Robert A. Millikan and Arthur H. Compton, both of whom came to win the Nobel Prize. Michelson himself won the Nobel Prize in 1907, the first American to do so. Millikan's fame came from the oil drop experiment he did at Chicago. This established in a dramatic way the discrete value of the electric charge, whose value he measured with extraordinary precision. He won the Nobel Prize for providing, by means of the photo-electric effect, an experimental proof of the existence of the photon. Arthur Compton came to Chicago in 1923, fresh from his discovery of the quantum nature of the scattering of X-rays by electrons, an effect that bears his name and which helped establish the ideas of quantum mechanics. In 1930, Compton's scientific interest and the stamp of the Physics Department shifted from precision X-ray measurements to cosmic rays. His very productive group of investigators in cosmic rays included at various times such men as Luis Alvarez, Pierre Auger, Marcel Shein, and Volney Wilson.
The size of the Department remained small and its emphasis on precise experiments continued through the 1930s. According to the catalog entry of the Department:
A feature on which considerable stress will be laid is the repetition of the classical experiments of eminent investigators by those graduate students who are able to undertake them. The object is to train the habits of careful, intelligent observation of the external world.
When theoretical physics emerged as an important discipline in its own right, the Department was ready with Robert Mulliken, who received the Nobel Prize for his work on molecular structure, and later Gregor Wentzel, Edward Teller, Maria Goeppert-Mayer, Clarence Zener, and S. Chandrasekhar to take an active role in it.
At the end of the Second World War, Enrico Fermi conducted with his scientific team the first self-sustaining nuclear chain reaction and again established the Department as one of the leading centers of physics. A new style of doing physics emerged, and the Department took on a new look. The Research Institutes became established, and the appointments in physics to the Research Institutes were made jointly with the Physics Department. Fermi's influence was very great. He was equally at home with both theory and experiment. Theoretical physics came to play a major role at Chicago. The subsequent Nobel Prizes that can be directly ascribed to Fermi's influence -- to Chen Ning Yang and Tsung-Dao Lee, to Owen Chamberlain, to Maria Goeppert-Mayer and Murray Gell-Mann -- were in theoretical as well as in experimental physics.
Fermi inspired excellence in teaching and a close teamwork with graduate students. The training of the next generation of great scientists as well as scholarship and research of the highest possible caliber define the mission of the Department to this day.
A large number of discoveries and scientific contributions were made by members of the Physics Department during the following decades. Robert Mulliken, Clemens Roothaan, and Ugo Fano made Chicago one of the world centers of molecular and atomic theory. Mark Inghram pioneered the application of mass spectrometers to determine nuclear constants, which led to the discovery of new isotopes. S.Chandrasekhar developed the basic theoretical framework for understanding much of stellar structure, radiative transfer, galactic dynamics, astrophysical plasmas, and the properties of rotating black holes. He received the Nobel Prize in 1983. Herbert Anderson discovered that one of the fundamental particles of nature, the proton, has an excited state. Eugene Parker predicted the solar wind, an outward flow of charged particles from the sun. John Simpson, in satellite experiments, confirmed the existence of the solar wind. He also linked the production of interplanetary deuterium and tritium with solar flares. Peter Meyer discovered the ratios of intensities of cosmic ray components, thus providing a clue to understanding the origin of cosmic rays.
Yoichiro Nambu's ideas on spontaneous breakdown of symmetries have had a profound impact on the development of elementary particle physics. Gregor Wentzel made important contributions to quantum electrodynamics, the gauge problem in superconductivity, and our understanding of strange particles. Robert R. Wilson built the Fermi National Accelerator, one of the most powerful instruments for probing the structure of elementary particles.
The present view of particle physics, that quarks and leptons are the basic constituents of matter, has been a long time coming. Part of the basis for these ideas originated here at the University's Synchrocyclotron. In the 1950s Enrico Fermi, Herbert Anderson, and others found out much about pi mesons and discovered excited states of the proton. Valentine Telegdi and his students carried out many remarkable experiments on weak interactions. Later James Cronin, Nobel Laureate of 1980, and several young University of Chicago physicists joined in the experiments at Argonne National Laboratory and Fermi National Accelerator Laboratory uncovering phenomena giving strong support to the quark-lepton view of matter. Much is revealed; much remains undiscovered.
Willliam Zachariasen determined the structure of silicates and glasses and of man-made transuranium elements created in the release of nuclear energy. Morrel Cohen and J.C.Phillips developed the pseudopotential theory which permits the calculation of the electronic band structure of solids. Hellmut Fritzsche elucidated the low-temperature electronic transport properties and the metal to nonmetal transition in semiconductors. The dielectric theory of J.C.Phillips explained the relation of the optical, structural, and chemical properties of semiconductors. L.Meyer and F.Reif discovered vortex rings in superfluid helium. Albert Crewe brought the development of the scanning electron microscope to its finest resolution and was the first to see the motion of single atoms. Roland Winston developed the ideal light collector, which has become an important scientific tool and which optimizes light collection from the sun.
New frontiers of physics are emerging. Leo Kadanoff, who received the Wolf Prize in 1980 for innovating the idea that led to the powerful renormalization methods, discovered a new global fractal formalism that describes paths to turbulence. Albert Libchaber, who was honored with the Wolf Prize in 1986, has carried out a study of nonlinear physical systems, with the expectation that universal features are shared by the entire class of diverse nonlinear processes. Peter Meyer and Dietrich Müller are analyzing the wealth of data on ultra-ultrahigh energy cosmic rays they gathered during the very successful space shuttle flight of their huge transition radiation detetctor. John Simpson went to the Soviet Union, where his novel dust particle detector turned out to be the crucial instrument on the Soviet spacecraft, Vega, measuring the concentration and the mass distribution of dust particles around Halley's Comet.
-Hellmut Fritzsche, May 1986
From the perspective of the thirty years since Professor Fritzsche wrote the above account, several further facts and events seemed worth noting.
Chapter One mentions the new style of research that developed at Chicago in the wake of the wartime research programs of the forties. The new style recognized the role of cross-disciplinary interaction in enabling the remarkable advances in science during the war. Accordingly three new "Research Institutes" were established as the primary seat of physics research. Each Institute assembled physicists and other disciplines appropriate to its field of study. Two of the three exist to the present day. The Institute for Nuclear Studies (now the Enrico Fermi Institute) addressed sub-atomic physics. The Institute for the study of Metals (now the James Franck Institute addressed collective atomic phenomena as seen, e.g, in condensed matter. The Institute for Radiobiology and Biophysics, led by Leo Szilard, launched medical research later to be taken up by the Biological Sciences Division of the University. The interdisciplinary style of the Institutes had a broad influence on academic research as a whole. Encouraged by their success, US funding agencies instituted the Materials Research Laboratories at a dozen other universities. This style of funding for collaborative research is still much in evidence in the NSF's Materials Research Science and Engineering Centers, in which Chicago remains as a strong participant.
The flourishing of cosmic ray physics noted also had a theoretical complement. David Schramm, who joined the Astronomy Department in 1974, recognized that modern vestiges of the Big Bang origins of the universe contain precious information about its ultimate constituents, the elementary particles. His leadership in connecting elementary particle physics with cosmology came to be a vital part of both fields, and the colleagues he attracted to Chicago have made it a leading center of cosmology, as will be told in Chapter Two. Likewise, Chandrasekhar founded a distinguished group in general relativity including Wald, Hartle and Geroch which set the stage for recent prominence.
Yoshiro Nambu was mentioned for his recognition of how spontaneous symmetry breaking affects subatomic phenomena. Beyond this, Nambu showed how spontaneous breaking of local symmetry can create massive particles and laid the groundwork for several aspects of the comprehensive description of particle phenomena known as the Standard Model.
Chapter One noted the importance of the Department's work in strong-interaction physics. Complementing this work was a world-leading effort in weak-interaction physics, led by Cronin and Bruce Winstein. It aimed to understand the violation of charge conjugation and parity symmetries (CP violation). By identifying a pattern of rare decay modes of weakly unstable particles, the weakly-interacting sector of the Standard Model was established in its present form.
Seminal role of Kadanoff and his colleagues in understanding magnification or scale invariance in phase transitions and in turbulence was noted in Chapter One. Another major aspect of this work was a comprehensive account of the power laws seen in two-dimensional phase transitions by Shenker and Friedan. Their landmark 1984 paper revealed how conformal invariance strongly constrains a broad range of two-dimensional power-law phenomena.
William Zachariasen was noted for his characterization of glassy disorder in solids. He also had a profound impact on the department as Chairman from 1945 to 1950. Under his leadership the governance of the department became collaborative and democratic. He attracted the giants who joined the department after World War II.
-Thomas Witten, April 2018