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Paul Dirac
Times obituary
A founder of quantum mechanics
Professor Paul Adrien Maurice Dirac, OM, FRS, who won the Nobel Prize for physics in 1933, died on October 20 in Florida, United States, at the age of 82. He was Professor of Mathematics at Cambridge from 1932 to 1969.
Dirac was born on August 8, 1902, at Bristol, the son of a Swiss father and an English mother. He attended the Merchant Venturers School, Bristol, and afterwards Bristol University, where he graduated in electrical engineering in 1921.
After two years of studying mathematics, he entered St. John's College, Cambridge, in 1923 as an exhibitioner and research student. In 1925, he made his reputation by publishing a paper that established the fundamental principles of quantum mechanics and led to the demonstration of the equivalence of the apparently dissimilar formalisms being developed by Schrödinger and Heisenberg.
Dirac then turned his attention to the combination of relativity and quantum theory, laying the foundations of quantum field theory through his discussion of the electromagnetic field and making his greatest discovery by formulating the relativistic equation of the electron. The theory of the positron, the first example of antimatter, followed, along with its triumphant experimental confirmation shortly afterwards.
This brilliant sequence of researches established Dirac as the greatest British theoretical physicist since Maxwell and led to the award of the Nobel Prize in 1933. His active professional life continued for 40 more years, but he did not achieve again the splendid successes of that early work.
He was a man of very well-defined interests and tastes, with little sympathy either for the complexities of nuclear physics or for the somewhat inelegant mathematical procedures which were to bring important further developments in quantum electrodynamics, the subject he had founded.
In 1930, the first edition of his book The Principles of Quantum Mechanics appeared. It established itself as one of the great classics of scientific literature. His lectures at Cambridge were closely modelled on it, and they conveyed to generations of students a powerful impression of the coherence and cleverness of quantum theory. They constituted his principal contribution to education, for he took very few research students.
Dirac brought to his private life the logical directness he used to such effect in his scientific work. Many stories illustrating this have circulated, of which his attitude to a questioner at the end of a lecture is typical. The man indicated that he had not followed a particular point of Dirac's argument. A silence followed, and at last the chairman asked if Professor Dirac would deal with the question. "It was a statement, not a question," came the reply.
Dirac became a Fellow of the Royal Society in 1930, received his Royal Medal in 1939 and the Copley Medal in 1952. He was elected Lucasian Professor of Mathematics at Cambridge in 1932, and then was Professor Emeritus. From 1971 he was Professor of Physics at Florida State University. In 1973 he was appointed to the Order of Merit.
In 1937 he married Margit Wigner of Budapest, the sister of Eugene Wigner, a distinguished theoretical physicist. They had two children of the marriage.
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Dr. P. Goddard and Professor J. C. Taylor write:
Your obituary of P. A. M. Dirac (October 25) justly stressed his outstanding contribution to quantum theory in the years 1925 to 1933. But perhaps the very emphasis on this work tends, by comparison, to make one lose sight of the extraordinary perfection of nearly all his writings.
His later work on such topics as the theory of magnetic monopoles, the dynamics of constrained systems, extended models of elementary particles and steps towards a quantum theory of gravity did not have the same immediate impact as his great contributions to the development of quantum theory.
But, as time goes by, physicists have come more and more to appreciate the importance of the later work. An example of this is the great interest in the last ten years in the possible existence of magnetic monopoles. Dirac's 50-year-old work on this subject relates closely to the most recent ideas on unified theories of the fundamental forces of nature.
A founder of quantum mechanics
Professor Paul Adrien Maurice Dirac, OM, FRS, who won the Nobel Prize for physics in 1933, died on October 20 in Florida, United States, at the age of 82. He was Professor of Mathematics at Cambridge from 1932 to 1969.
Dirac was born on August 8, 1902, at Bristol, the son of a Swiss father and an English mother. He attended the Merchant Venturers School, Bristol, and afterwards Bristol University, where he graduated in electrical engineering in 1921.
After two years of studying mathematics, he entered St. John's College, Cambridge, in 1923 as an exhibitioner and research student. In 1925, he made his reputation by publishing a paper that established the fundamental principles of quantum mechanics and led to the demonstration of the equivalence of the apparently dissimilar formalisms being developed by Schrödinger and Heisenberg.
Dirac then turned his attention to the combination of relativity and quantum theory, laying the foundations of quantum field theory through his discussion of the electromagnetic field and making his greatest discovery by formulating the relativistic equation of the electron. The theory of the positron, the first example of antimatter, followed, along with its triumphant experimental confirmation shortly afterwards.
This brilliant sequence of researches established Dirac as the greatest British theoretical physicist since Maxwell and led to the award of the Nobel Prize in 1933. His active professional life continued for 40 more years, but he did not achieve again the splendid successes of that early work.
He was a man of very well-defined interests and tastes, with little sympathy either for the complexities of nuclear physics or for the somewhat inelegant mathematical procedures which were to bring important further developments in quantum electrodynamics, the subject he had founded.
In 1930, the first edition of his book The Principles of Quantum Mechanics appeared. It established itself as one of the great classics of scientific literature. His lectures at Cambridge were closely modelled on it, and they conveyed to generations of students a powerful impression of the coherence and cleverness of quantum theory. They constituted his principal contribution to education, for he took very few research students.
Dirac brought to his private life the logical directness he used to such effect in his scientific work. Many stories illustrating this have circulated, of which his attitude to a questioner at the end of a lecture is typical. The man indicated that he had not followed a particular point of Dirac's argument. A silence followed, and at last the chairman asked if Professor Dirac would deal with the question. "It was a statement, not a question," came the reply.
Dirac became a Fellow of the Royal Society in 1930, received his Royal Medal in 1939 and the Copley Medal in 1952. He was elected Lucasian Professor of Mathematics at Cambridge in 1932, and then was Professor Emeritus. From 1971 he was Professor of Physics at Florida State University. In 1973 he was appointed to the Order of Merit.
In 1937 he married Margit Wigner of Budapest, the sister of Eugene Wigner, a distinguished theoretical physicist. They had two children of the marriage.
________________________________________________
Dr. P. Goddard and Professor J. C. Taylor write:
Your obituary of P. A. M. Dirac (October 25) justly stressed his outstanding contribution to quantum theory in the years 1925 to 1933. But perhaps the very emphasis on this work tends, by comparison, to make one lose sight of the extraordinary perfection of nearly all his writings.
His later work on such topics as the theory of magnetic monopoles, the dynamics of constrained systems, extended models of elementary particles and steps towards a quantum theory of gravity did not have the same immediate impact as his great contributions to the development of quantum theory.
But, as time goes by, physicists have come more and more to appreciate the importance of the later work. An example of this is the great interest in the last ten years in the possible existence of magnetic monopoles. Dirac's 50-year-old work on this subject relates closely to the most recent ideas on unified theories of the fundamental forces of nature.
