Freeman Dyson

Freeman John Dyson (December 15, 1923 to February 28, 2020) was an English-born American theoretical physicist and writer. In a paper of 1949 he showed that the formulations of quantum electrodynamics by Tomonaga, Schwinger and Feynman are equivalent. In 1960 he suggested that an advanced civilization might be found by the infrared radiation of structures built around its star, which came to be called a Dyson sphere. He also worked on reactor design, on the atomic spaceship of Project Orion and on arms control. He spent most of his career at the Institute for Advanced Study in Princeton, never earned a doctorate, and wrote popular books and essays, among them "Our Biotech Future" (2007).^[1]

Dyson was born in Crowthorne, Berkshire. His father, George Dyson, was a composer who was later knighted, and his mother, Mildred Atkey, was a law graduate who became a social worker. He was educated at Winchester College, where his father was director of music, and won a scholarship to Trinity College, Cambridge, which he entered in 1941 to read mathematics.^[2] From 1943 to 1945 he worked as a civilian in the Operational Research Section of RAF Bomber Command, where he developed methods for calculating the best density of bombers in a formation. He took his degree in 1945.^[1][2]

A Commonwealth Fellowship took Dyson to Cornell University in 1947, where he worked with Hans Bethe and Richard Feynman. In the spring of 1948, traveling alone by bus, he had the insight that proved Feynman's and Schwinger's theories equivalent, which he described as a "flash of illumination on the Greyhound bus".^[1] The paper that followed, "The Radiation Theories of Tomonaga, Schwinger, and Feynman", was received by Physical Review on October 6, 1948, and appeared in February 1949. It demonstrated the equivalence of the Feynman and Schwinger theories and simplified the use of Schwinger's method on particular problems.^[3] It allowed Feynman's diagrams to be used to calculate scattering amplitudes. The Nobel Prize in Physics for the theory went to Feynman, Schwinger and Tomonaga in 1965, and Dyson never received one.^[1][2]

Dyson spent 1948 to 1949 at the Institute for Advanced Study (IAS) as a member, then returned to England as a research fellow at the University of Birmingham from 1949 to 1951. In 1951 he accepted a professorship of physics at Cornell, although he had no doctorate. In December 1952 J. Robert Oppenheimer, the director of the IAS, offered him a permanent post, which he took up in 1953. He became a citizen of the United States in 1957 and retired from the IAS in 1994 as professor emeritus.^[2][1]

From 1956 Dyson worked for General Atomic on an inherently safe research reactor, whose TRIGA design remains in use. In 1958 he joined Project Orion, a study at the company's site in La Jolla, California, of a spacecraft driven by a series of nuclear explosions, and he later called it one of the happiest periods of his scientific life. The project was abandoned in 1965, after the Partial Test Ban Treaty of 1963 left only underground testing.^[1][2] From 1962 he chaired the council of the Federation of American Scientists, and in 1963 he testified in favor of the treaty.^[1]

In 1960 Science published a two-page paper by Dyson, "Search for Artificial Stellar Sources of Infrared Radiation". It argued that an intelligent species using the light of its star would give off the energy as far-infrared radiation, and proposed a search for such sources alongside the radio search for interstellar messages.^[4] The structure it implied, a shell or swarm of matter around a star, is called a Dyson sphere, and is a standard example in discussions of the Kardashev scale.

Dyson published on number theory, analysis and algebraic topology, and he helped to build the theory of random matrices.^[1] A conversation in 1972 joined his work on random matrices to number theory. At tea at the IAS in April of that year, the number theorist Hugh Montgomery described a formula he had found for the pair correlation of the zeros of the Riemann zeta function. By Montgomery's recollection, Dyson recognized it as the pair correlation of the eigenvalues of random matrices in the Gaussian unitary ensemble. Later numerical work by Andrew Odlyzko supported the match.^[5]

In 1975 Dyson began to write for general readers, following advice from G. H. Hardy that "Young men should prove theorems, old men should write books."^[1] His books include the memoir Disturbing the Universe (1979), Weapons and Hope (1984), Infinite in All Directions (1988), The Sun, the Genome, and the Internet (1999) and Maker of Patterns (2018), an autobiography in letters.^[2] In October 2004, in a lecture at Cornell, he said that John von Neumann "failed to foresee the final domestication of computers as toys for three-year-olds", and he expected biotechnology to follow computing into the home.^[6] "Our Biotech Future", published three years later in The New York Review of Books, makes the case at length.

In later life Dyson disagreed with the scientific consensus on climate change. He accepted that human activity is warming the planet, but he doubted the climate models and argued that the effects of extra carbon dioxide, such as faster growth of crops and forests, could be beneficial.^[7][2]

Dyson was a Fellow of the Royal Society and a member of the United States National Academy of Sciences. His awards include the Lorentz Medal (1966), the Max Planck Medal (1969), the Wolf Prize in Physics (1981), the Templeton Prize (2000) and the Henri Poincaré Prize (2012).^[1]

Dyson married the Swiss mathematician Verena Huber in 1950, and they divorced in 1958. Their son George Dyson became a historian of technology. Their daughter Esther Dyson, born in 1951, is an investor and writer on technology. In November 1958 Dyson married Imme Jung, and they had four daughters. He died on February 28, 2020, at the age of 96, of complications after a fall.^[2][1]

On its fourteenth page, the December 2022 scientific and technical overview of Molecular Reality Corporation prints a pull quotation over Dyson's name: "We should follow the model that's been so successful with the electronic industry that what really turned computers into a great success in the world as a whole is toys. As soon as computers became toys, when kids could come home and play with them, then the industry really took off. And that has to happen with biotech." The overview does not say where the words were recorded.^[8] Dyson made a similar argument in print in "Our Biotech Future". The company's motto "advanced scientific instruments disguised as toys" is the subject of Biopopulism.

• Esther Dyson
• Ideas and influences of Molecular Reality Corporation
• List of works that inspired Molecular Reality Corporation