APS News

A Century of Physics

1945-1954: The Post War Boom

By Hans Christian von Baeyer

Richard Feynman
In the United States the successful conclusion of World War II inspired a heady sense of optimism and self-confidence which was further bolstered by the end of the Great Depression. Renewed prosperity, in turn, allowed America to contribute generously to the reconstruction of the world's shattered nations. Neither the emerging Cold War, nor the sudden eruption of the Korean conflict in 1951, could dampen the good spirits. Physics, too, blossomed as young scientists returned to their universities and industrial labs, full of new ideas picked up in the course of their war work, and eager to get on with their careers. Far from closing down, weapons laboratories developed into permanent national institutions devoted to both military and civilian research. For the first time, the federal government undertook the systematic support of basic science.

One of the theoreticians who came down from Oppenheimer's mountain-top in New Mexico was Richard Feynman (right), a native New Yorker just three years past his Ph.D. Brilliant, irreverent, and ambitious, he distrusted authority and insisted on figuring things out in his own way. His particular strength was his visual imagination. For example, he developed an elegant code for representing complex equations by simple diagrams that allowed him to let his physical intuition guide his mathematical calculations toward quick, accurate solutions.

Feynman brought this unorthodox technique to bear on what was at the time the principal problem of theoretical physics: the quantum mechanics of light. Photons had been around for half a century, but a detailed description of how they are emitted and absorbed by electrons was lacking. Together with American colleagues and Japanese physicists who had worked along similar lines while they were out of touch with the West during the war, Feynman solved the problem by creating Quantum Electrodynamics (QED). QED proved to be of such unprecedented precision and scope that it set a standard of excellence against which all future fundamental theories of elementary particles would come to be measured.

In contrast to QED, which applies to the outer shell of the atom where the electrons reside, theoretical descriptions of the atomic nucleus remained rudimentary. Even as the list of so-called elementary particles produced at accelerators grew into the hundreds, theories proliferated, but none were mathematically satisfactory. Neither the aging giants, such as Werner Heisenberg, nor the young geniuses, such as Feynman, knew which way to turn. The tantalizing success of QED only added to their frustration.

Editor's Note: A CENTURY OF PHYSICS, a dramatic illustrated timeline wallchart of over a hundred entries on eleven large posters is intended for high schools and colleges. Each poster covers about a decade and is introduced by a thumbnail essay to provide a glimpse of the historical and scientific context of the time.

In the October issue, APS News will feature the seventh introductory essay: 1955-1965: Connections.

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Editor: Barrett H. Ripin