Physicist Tested Particle Actions
By WALTER SULLIVAN Published: October 10, 1990
John Stewart Bell, whose test for one of the most bizarre aspects of quantum physics led to its apparent confirmation, died last week at a hospital in Geneva. He was 62 years old.
He died after suffering a cerebral hemorrhage, said Dr. Jeremy Bernstein, professor of physics at the Stevens Institute of Technology in Hoboken, N.J., and a family friend.
Dr. Bell, who was on the staff of CERN, the European nuclear research center near Geneva, had been scheduled to give a lecture on quantum theory last Friday at New York University. He is known throughout the world of physics as originator of ”Bell’s theorem” or ”Bell’s inequality.”
His work addressed the question of whether particles, having flown too far apart for there to be normal communication between them, can still function in concert, as though activated by instant communication.
Resolving a Basic Question
Testing of his theorem seems to have shown that the particles carry no hidden message accounting for their coordinated behavior. Instead, the apparent coordination arises from the action of measurement.
The tests appear to have resolved one of the most basic questions in physics: Is there some sort of message, a ”hidden variable,” within the basic particles that determines their otherwise seemingly random behavior? For example, the atoms in a particular form of radioactive material collectively decay at a predictable rate, but there is no known way to predict when any one of them will do so.
Such behavior is characteristic of quantum physics, but Einstein suspected that there might be a hidden message, something within each particle that predetermined when it would decay. In a famous comment, he said that God does not ”play at dice.”
Bell’s theorem drew little notice when published in 1964, but five years later physicists realized that the proposition could be tested by experiment. Since then, as noted by Dr. Bernstein in a book, ”Quantum Profiles,” soon to be published by Princeton University Press, a variety of such experiments have been carried out. Most have supported the quantum viewpoint.
Despite discouragement by Dr. Bell and other physicists, some of the evidence from experiments testing his theorem, suggesting communication between particles, has been seized upon as support for mental telepathy and other exotic or mystical behavior.
Dr. Bell was born in Belfast, Northern Ireland, to working-class parents with little education. In 1949 he graduated from Queens College in Belfast, then studied under Sir Rudolph Peierls at the University of Birmingham in England. He joined the Atomic Energy Research Establishment in Harwell, which sent him to a substation at Malvern in Worcestershire, where he worked on designing atomic accelerators and met the woman who became his wife, Mary.
In 1952 he began consulting with CERN on the design for its first particle accelerator and eventually joined its staff.
Dr. Bell is survived by his wife, who was also a physicist at CERN, and several siblings.