Paul Dirac
Paul Adrien Maurice Dirac was born on the 8th of August 1902 at his parents' home in Bristol, England. His father Charles Adrien Ladislas Dirac came from Saint-Maurice, Switzerland and worked as a French teacher. The elder Dirac enforced a strict rule that all children must speak only to him in French. Young Paul found he could not express what he wanted to say in that language so he chose to remain silent instead. This silence became a defining trait of his character for decades to come. He grew up in the Bishopston area of Bristol with a younger sister named Betty and an older brother Felix who died by suicide in March 1925. The family tragedy left a deep mark on the young physicist who later recalled never knowing that parents were supposed to care for their children.
Dirac formulated the relativistic equation for the electron in 1928 while working at Cambridge University. This mathematical breakthrough connected special relativity with quantum mechanics in a way no one had done before. The equation predicted the existence of antimatter through the concept of the positron. Carl Anderson observed this particle experimentally in 1932 confirming Dirac's theoretical prediction. The work led to the creation of quantum field theory which underlies all modern theoretical physics regarding subatomic particles. Dirac also proposed the existence of magnetic monopoles as a means to bring greater symmetry to James Clerk Maxwell's equations of electromagnetism. No such monopole has been detected despite numerous attempts over many years.
Colleagues in Cambridge jokingly defined a unit called a dirac equal to one word per hour. Albert Einstein wrote in a 1926 letter about Dirac that he was toiling over him and found the balancing act between genius and madness awful. Niels Bohr once described Dirac as the strangest man who had ever visited his Institute. During a conference sailing trip to Japan in August 1929 Werner Heisenberg danced with women while Dirac suffered agonies if forced into socializing. When asked why he did not dance Dirac replied asking how Heisenberg knew beforehand that the girls were nice. He criticized J. Robert Oppenheimer's interest in poetry stating that science aims to make difficult things understandable while poetry states simple things incomprehensibly.
Dirac wrote on a blackboard at Moscow State University in 1956 the phrase Physical laws should have mathematical beauty. This inscription remains there today as traditional for distinguished visitors. He repeatedly emphasized that mathematical beauty served both as a quality of nature and a methodological guide for physicists. In a 1939 lecture he argued that the mathematically beautiful statement of general relativity was one reason it was accepted. He famously stated that God is a mathematician of a very high order using advanced mathematics to construct the universe. His approach led him to reject renormalization techniques used by other theorists because they involved neglecting infinities arbitrarily rather than when small.
During World War II Dirac contributed to the Tube Alloys project which researched atomic bombs for Britain. He made fundamental contributions to uranium enrichment processes including work on gas centrifuges deemed probably the most important theoretical result in centrifuge technology. He introduced the separative work unit in 1941 to measure the efficiency of these separation processes. Later in life he discussed why gravitational waves had physical significance during a 1959 lecture at Lindau Meetings. He predicted gravitational waves would have well defined energy density in 1964 and reintroduced the term graviton in several lectures from 1959 onward.
Dirac moved his family to Tallahassee, Florida in September 1970 to accept a visiting professor position at Florida State University. He walked about a mile each day to work and swam in Silver Lake or Lost Lake nearby. The summer heat proved oppressive so he often escaped back to Cambridge during warmer months. At FSU he ate lunch with colleagues before taking a nap daily. He published over 60 papers during those last twelve years of his life including a short book on general relativity. His final paper written in 1984 contained his judgment that renormalization rules gave surprisingly good agreement with experiments but did not prove theories correct.
Paul Dirac died on the 20th of October 1984 in Tallahassee, Florida at the age of 82. He was buried at Roselawn Cemetery alongside his wife Margit who passed away earlier. A commemorative marker made from Burlington green slate inscribed with the Dirac equation was unveiled in Westminster Abbey on the 13th of November 1995. The Institute of Physics awards an annual Paul Dirac Medal for outstanding contributions to theoretical physics since 1985. An asteroid discovered in 1983 bears his name and the BBC named a video codec after him. Richard Dalitz wrote that the influence and importance of Dirac's work have increased with the decades as physicists use concepts developed by him daily.
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Common questions
When and where was Paul Dirac born?
Paul Adrien Maurice Dirac was born on the 8th of August 1902 at his parents' home in Bristol, England. His father Charles Adrien Ladislas Dirac came from Saint-Maurice, Switzerland and worked as a French teacher.
What major equation did Paul Dirac formulate in 1928?
Dirac formulated the relativistic equation for the electron in 1928 while working at Cambridge University. This mathematical breakthrough connected special relativity with quantum mechanics and predicted the existence of antimatter through the concept of the positron.
Why was Paul Dirac known for being silent during his childhood?
His father enforced a strict rule that all children must speak only to him in French so young Paul chose to remain silent instead. This silence became a defining trait of his character for decades to come.
How did Paul Dirac contribute to atomic bomb research during World War II?
During World War II Dirac contributed to the Tube Alloys project which researched atomic bombs for Britain. He made fundamental contributions to uranium enrichment processes including work on gas centrifuges deemed probably the most important theoretical result in centrifuge technology.
Where did Paul Dirac move his family in September 1970?
Paul Dirac moved his family to Tallahassee, Florida in September 1970 to accept a visiting professor position at Florida State University. The summer heat proved oppressive so he often escaped back to Cambridge during warmer months.