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{{Short description|British theoretical physicist (1902–1984)}}{{Redirect|Dirac|other uses}}{{pp-semi-indef}}{{pp-vandalism|small=yes}}{{Use British English|date=January 2024}}{{Use dmy dates|date=January 2024}}

factoids

| image = Paul Dirac, 1933.jpg| caption = Dirac in 1933| birth_name = Paul Adrien Maurice Diracdf=y8|8}}| birth_place = Bristol, Englanddf=y1019028}}| death_place = Tallahassee, Florida, U.S.| nationality = BritishMargit Wigner|2 January 1937}}| children = 2| fields = Theoretical physics, mathematical physics

• University of Cambridge
• University of Miami
• Florida State University

{edih}

• University of Bristol
• University of Cambridge

{edih}| doctoral_advisor = Ralph Fowler| thesis_title = Quantum Mechanics| thesis_url =www.worldcat.org/oclc/15668650| thesis_year = 1926

• Homi J. BhabhaTHESIS, PhD,www.repository.cam.ac.uk/handle/1810/250819, On cosmic radiation and the creation and annihilation of positrons and electrons, Homi Jehangir, Bhabha, 1935, {{EThOS, uk.bl.ethos.727546, |publisher=University of Cambridge}}
• Harish-ChandraHarish-Chandra, School of Mathematics and Statistics, University of St Andrews.
• Dennis Sciama
• Fred Hoyle
• Behram KurÅŸunoÄŸluDeWitt, C. M., & Rickles, D., eds., The Role of Gravitation in Physics: Report from the 1957 Chapel Hill Conference (Berlin: Edition Open Access, 2011), p. 30.
• John PolkinghorneTHESIS, PhD,idiscover.lib.cam.ac.uk/primo-explore/fulldisplay?docid=44CAM_ALMA21428195830003606&context=L&vid=44CAM_PROD&search_scope=SCOP_CAM_ALL&tab=cam_lib_coll&lang=en_US, Contributions to quantum field theory, John Charlton, Polkinghorne, 1955, {{EThOS, uk.bl.ethos.727138, |publisher=University of Cambridge}} C. J. Eliezer

}}

• One of the founders of quantum mechanics and quantum electrodynamics
• See list

{edih}

• Nobel Prize in Physics (1933)
• Royal Medal (1939)
• Copley Medal (1952)
• Max Planck Medal (1952)
• {{nowrap|Fellow of the Royal Society (1930){edih} }}| footnote =

}}{{Quantum mechanics}}{{Special relativity sidebar}}File:Clara Ewald - Paul Dirac.jpg|thumb|upright|Portrait of Paul Dirac by Clara EwaldClara EwaldPaul Adrien Maurice Dirac {{post-nominals|country=GBR|OM|FRS}}JOURNAL, Dalitz, R. H., Richard Dalitz, Peierls, R., Rudolf Peierls, 10.1098/rsbm.1986.0006, Paul Adrien Maurice Dirac. 8 August 1902 – 20 October 1984, Biographical Memoirs of Fellows of the Royal Society, 32, 137–185, 1986, 770111, free, ({{IPAc-en|d|ɪ|ˈ|r|æ|k}}; 8 August 1902 – 20 October 1984) was an English mathematical and theoretical physicist who is considered to be one of the founders of quantum mechanics and quantum electrodynamics.BOOK, Simmons, John,archive.org/details/100mostinfluenti0000simm, The Scientific 100: A Ranking of the Most Influential Scientists, Past and Present, Carol Publishing Group, 1997, 978-0806517490, Secaucus, New Jersey, 104–108, en, Mukunda, N., Images of Twentieth Century Physics (Bangalore: Jawaharlal Nehru Centre for Advanced Scientific Research, 2000), p. 9. He is credited with laying the foundations of quantum field theory.BOOK, Duck, Ian,archive.org/details/paulispinstatist0000unse/mode/2up, Pauli and the Spin-Statistics Theorem, Sudarshan, E.C.G., World Scientific Publishing, 1998, 978-9810231149, 149–167, en, Chapter 6: Dirac’s Invention of Quantum Field Theory, E.C.G. Sudarshan, JOURNAL, Bhaumik, Mani L., 2022, How Dirac’s Seminal Contributions Pave the Way for Comprehending Nature’s Deeper Designs, Quanta, 8, 1, 88–100, 10.12743/quanta.v8i1.96, 2209.03937, 212835814, He was the Lucasian Professor of Mathematics at the University of Cambridge, a professor of physics at Florida State University and the University of Miami, and a 1933 Nobel Prize in Physics recipient.Dirac graduated from the Universty of Bristol with a first class honours Bachelor of Science degree in electrical engineering in 1921, and graduated from the University of Cambridge with a PhD in physics in 1926, writing the first ever thesis on quantum mechanics.WEB, Paul Dirac - Magnet Academy,nationalmaglab.org/magnet-academy/history-of-electricity-magnetism/pioneers/paul-dirac/, 2024-05-07, nationalmaglab.org, en, Dirac made fundamental contributions to the early development of both quantum mechanics and quantum electrodynamics, coining the latter term.WEB, Quantum Field Theory > The History of QFT (Stanford Encyclopedia of Philosophy),plato.stanford.edu/entries/quantum-field-theory/qft-history.html, 22 October 2023, plato.stanford.edu, Among other discoveries, he formulated the Dirac equation in 1928, which describes the behaviour of fermions and predicted the existence of antimatter,WEB, Discovering the positron,timeline.web.cern.ch/timeline-header/142#416, 23 October 2023, timeline.web.cern.ch, and is considered one of the most important equations in physics,WEB, Berry, Michael, Michael Berry (physicist), 1 February 1998, Paul Dirac: the purest soul in physics,physicsworld.com/paul-dirac-the-purest-soul-in-physics/, 16 October 2023, Physics World, en-GB, with it being considered by some to be the “real seed of modern physics”.WEB, Zichichi, Antonino, Antonino Zichichi, 2 March 2000, Dirac, Einstein and physics,physicsworld.com/a/dirac-einstein-and-physics/, 22 October 2023, Physics World, en-GB, He wrote a famous paper in 1931,JOURNAL, Dirac, Paul, 1931, Quantised singularities in the electromagnetic field,royalsocietypublishing.org/doi/10.1098/rspa.1931.0130, Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character, en, 133, 821, 60–72, 10.1098/rspa.1931.0130, 1931RSPSA.133...60D, 0950-1207, which further predicted the existence of antimatter.JOURNAL, Gottfried, Kurt, 2011, P. A. M. Dirac and the discovery of quantum mechanics,pubs.aip.org/aapt/ajp/article-abstract/79/3/261/398648/P-A-M-Dirac-and-the-discovery-of-quantum-mechanics?redirectedFrom=fulltext, American Journal of Physics, 79, 3, 2, 10, 10.1119/1.3536639, 1006.4610, 2011AmJPh..79..261G, 18229595, {{Citation |last=Kragh |first=Helge |title=Paul Dirac and The Principles of Quantum Mechanics |date=10 September 2013 |url=https://mprl-series.mpg.de/studies/2/11/index.html |work=Research and Pedagogy: A History of Quantum Physics through Its Textbooks |access-date=23 October 2023 |series=MPRL – Studies |place=Berlin |publisher=Max-Planck-Gesellschaft zur Förderung der Wissenschaften |language=english |isbn=978-3-945561-24-9 |author-link=Helge Kragh}} Dirac shared the 1933 Nobel Prize in Physics with Erwin Schrödinger “for the discovery of new productive forms of atomic theory”.WEB,www.nobelprize.org/nobel_prizes/physics/laureates/1933/, The Nobel Prize in Physics 1933, The Nobel Foundation, 4 April 2013, He was the youngest ever theoretician to win the prize until T. D. Lee in 1957.WEB, Farmelo, Graham, 2008, Paul Dirac: The Mozart of Science,www.ias.edu/ideas/2008/farmelo-on-dirac, 2024-05-08, www.ias.edu, en, He also made significant contributions to the reconciliation of general relativity with quantum mechanics. His 1930 monograph, The Principles of Quantum Mechanics, is considered to be one of the most influential texts on quantum mechanics.JOURNAL, Brown, Laurie M., Laurie Brown (physicist), 2006, Paul A. M. Dirac’s Principles of Quantum Mechanics,faculty.washington.edu/seattle/physics441/online/about%20Dirac.pdf, Physics in Perspective, 8, 4, 381–407, 10.1007/s00016-006-0276-4, 2006PhP.....8..381B, 120303937, Dirac’s contributions were not only restricted to quantum mechanics. He contributed to the Tube Alloys project, the British programme to research and construct atomic bombs during World War II.ODNB, Cathcart, Brian, 25 May 2006, Tube Alloys directorate (act. 1941–1945),www.oxforddnb.com/display/10.1093/ref:odnb/9780198614128.001.0001/odnb-9780198614128-e-93791, 25 October 2023, en, 10.1093/ref:odnb/93791, THESIS, Vrobel, Daniel P., Paul Dirac: The Atomic Centrifuge and the Tube Alloys Project, 2020, Florida State University,diginole.lib.fsu.edu/islandora/object/fsu:770703/datastream/PDF/view, Master, Furthermore, Dirac made fundamental contributions to the process of uranium enrichment and the gas centrifuge,WEB, McKie, Robin, Robin McKie, 31 January 2009, Anti-matter and madness,amp.theguardian.com/books/2009/feb/01/strangest-man-paul-dirac-review, 24 October 2023, amp.theguardian.com, JOURNAL, Kemp, R. Scott, 26 June 2009, Gas Centrifuge Theory and Development: A Review of U.S. Programs, Science & Global Security, en, 17, 1, 1–19, 10.1080/08929880802335816, 0892-9882, free, 2009S&GS...17....1K, JOURNAL, Gilinsky, Victor, 2010, Remembrances of Dirac,pubs.aip.org/physicstoday/article/63/5/59/387409/Remembrances-of-Dirac, Physics Today, 63, 5, 59, 10.1063/1.3431338, free, 2010PhT....63e..59G, and whose work was deemed to be “probably the most important theoretical result in centrifuge technology”.{{harvnb|Kragh|1990|p=158}} He also contributed to cosmology, putting forth his large numbers hypothesis.JOURNAL, Dirac, Paul Adrien Maurice, 5 April 1938, A new basis for cosmology,royalsocietypublishing.org/doi/10.1098/rspa.1938.0053, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, en, 165, 921, 199–208, 10.1098/rspa.1938.0053, 1938RSPSA.165..199D, 121069801, 0080-4630, JOURNAL, Kragh, Helge, 2014, Paul Dirac and the Magic of Large Numbers,academic.oup.com/book/4223/chapter-abstract/146058250?redirectedFrom=fulltext, Masters of the Universe: Conversations with Cosmologists of the Past, 217–237, 10.1093/acprof:oso/9780198722892.003.0012, 978-0-19-872289-2, Oxford Academic, JOURNAL, Saibal, Ray, Mukhopadhyay, Utpal, Ray, Soham, Bhattacharjee, Arjak, 2019, Dirac’s large number hypothesis: A journey from concept to implication,www.worldscientific.com/doi/10.1142/S0218271819300143, International Journal of Modern Physics D, 28, 8, 1930014–1930096, 10.1142/S0218271819300143, 2019IJMPD..2830014R, 127899548, World Scientific, JOURNAL, Dubois, Eve-Aline, Füzfa, André, Lambert, Dominique, 2022, The large numbers hypothesis in cosmology,www.worldscientific.com/doi/10.1142/9789811258251_0259, The Fifteenth Marcel Grossmann Meeting, en, WORLD SCIENTIFIC, 1741–1744, 10.1142/9789811258251_0259, 2022mgm..conf.1741D, 978-981-12-5824-4, 225097737, Dirac is also seen as having anticipated string theory well before its inception, with his work on the Dirac membrane and Dirac–Born–Infeld action, amongst other contributions.Dirac was regarded by his friends and colleagues as unusual in character. In a 1926 letter to Paul Ehrenfest, Albert Einstein wrote of a Dirac paper, “I am toiling over Dirac. This balancing on the dizzying path between genius and madness is awful.” In another letter concerning the Compton effect he wrote, “I don’t understand the details of Dirac at all.“{{harvnb|Kragh|1990|p=82]}} “Dirac verstehe ich im Einzelnen überhaupt nicht (Compton-Effekt)” In 1987, Abdus Salam stated that “Dirac was undoubtedly one of the greatest physicists of this or any century . . . No man except Einstein has had such a decisive influence, in so short a time, on the course of physics in this century.“BOOK, Kursunoglu, Behram N.,archive.org/details/pauladrienmauric0000unse, Paul Adrien Maurice Dirac: Reminiscences about a Great Physicist, Wigner, Eugene P., Cambridge University Press, 1987, 262, 9780521340137, en, In 1995, Stephen Hawking stated that “Dirac has done more than anyone this century, with the exception of Einstein, to advance physics and change our picture of the universe”.WEB, 25 August 2009, The Strangest Man: The Hidden Life of Paul Dirac, Quantum Genius,cerncourier.com/a/the-strangest-man-the-hidden-life-of-paul-dirac-quantum-genius/, 22 October 2023, CERN Courier, en-GB, Antonino Zichichi asserted that Dirac had a greater impact on modern physics than Einstein. Dirac’s achievements are considered to be on par with Sir Isaac Newton, James Clerk Maxwell and Einstein.BOOK, Hey, Tony,archive.org/details/quantumuniverse0000heya/mode/1up, The Quantum Universe, Walters, Patrick, Cambridge University Press, 1987, 978-0521267441, 124, en, Tony Hey, JOURNAL, Close, Frank, 20 May 2009, Paul Dirac: a physicist of few words, Nature, en, 459, 7245, 326–327, 10.1038/459326a, 1476-4687, free, 2009Natur.459..326C, {{sfn|Kragh|1990|pp=ix, 12}}

Personal life

Early years

Paul Adrien Maurice Dirac was born at his parents’ home in Bristol, England, on 8 August 1902,{{harvnb|Farmelo|2009|p=10}} and grew up in the Bishopston area of the city.{{harvnb|Farmelo|2009|pp=18–19}} His father, Charles Adrien Ladislas Dirac, was an immigrant from Saint-Maurice, Switzerland, of French descent, who worked in Bristol as a French teacher. His mother, Florence Hannah Dirac, née Holten, was born to a Cornish Methodist family in Liskeard, Cornwall.WEB, Paul Dirac: a genius in the history of physics,cerncourier.com/cws/article/cern/28693, Cern Courier, 4 February 2022, 15 August 2002, {{harvnb|Farmelo|2009|pp=8, 441}} She was named after Florence Nightingale by her father, a ship’s captain, who had met Nightingale while he was a soldier during the Crimean war.{{harvnb|Farmelo|2009|pp=8}} His mother moved to Bristol as a young woman, where she worked as a librarian at the Bristol Central Library; despite this she still considered her identity to be Cornish rather than English.{{harvnb|Farmelo|2009|pp=441}} Paul had a younger sister, Béatrice Isabelle Marguerite, known as Betty, and an older brother, Reginald Charles Félix, known as Felix,{{harvnb|Kragh|1990|p=1}}{{harvnb|Farmelo|2009|pp=10–11}} who died by suicide in March 1925.{{harvnb|Farmelo|2009|pp=77–78}} Dirac later recalled: “My parents were terribly distressed. I didn’t know they cared so much ... I never knew that parents were supposed to care for their children, but from then on I knew.“{{harvnb|Farmelo|2009|p=79}}Charles and the children were officially Swiss nationals until they became naturalised on 22 October 1919.{{harvnb|Farmelo|2009|p=34}} Dirac’s father was strict and authoritarian, although he disapproved of corporal punishment.{{harvnb|Farmelo|2009|p=22}} Dirac had a strained relationship with his father, so much so that after his father’s death, Dirac wrote, “I feel much freer now, and I am my own man.” Charles forced his children to speak to him only in French so that they might learn the language. When Dirac found that he could not express what he wanted to say in French, he chose to remain silent.{{harvnb|Mehra|1972|p=17}}{{harvnb|Kragh|1990|p=2}}

Education

Dirac was educated first at Bishop Road Primary School{{harvnb|Farmelo|2009|pp=13–17}} and then at the all-boys Merchant Venturers’ Technical College (later Cotham School), where his father was a French teacher.{{harvnb|Farmelo|2009|pp=20–21}} The school was an institution attached to the University of Bristol, which shared grounds and staff. It emphasised technical subjects like bricklaying, shoemaking and metalwork, and modern languages.{{harvnb|Farmelo|2009|p=23}} This was unusual at a time when secondary education in Britain was still dedicated largely to the classics, and something for which Dirac would later express his gratitude.{{harvnb|Mehra|1972|p=18}}Dirac studied electrical engineering on a City of Bristol University Scholarship at the University of Bristol’s engineering faculty, which was co-located with the Merchant Venturers’ Technical College.{{harvnb|Farmelo|2009|p=28}} Shortly before he completed his degree in 1921, he sat for the entrance examination for St John’s College, Cambridge. He passed and was awarded a £70 scholarship, but this fell short of the amount of money required to live and study at Cambridge. Despite having graduated with a first class honours Bachelor of Science degree in electrical engineering, the economic climate of the post-war depression was such that he was unable to find work as an engineer. Instead, he took up an offer to study for a Bachelor of Arts degree in mathematics at the University of Bristol free of charge. He was permitted to skip the first year of the course owing to his engineering degree.{{harvnb|Farmelo|2009|pp=46–47}} Under the influence of Peter Fraser, whom Dirac called the best mathematics teacher, he had the most interest in projective geometry, and began applying it to the geometrical version of relativity Minkowski developed.JOURNAL, Galison, Peter, 2000, The Suppressed Drawing: Paul Dirac’s Hidden Geometry,www.jstor.org/stable/2902912, Representations, 72, 145–166, 10.2307/2902912, 2902912, 0734-6018, In 1923, Dirac graduated, once again with first class honours, and received a £140 scholarship from the Department of Scientific and Industrial Research.{{harvnb|Farmelo|2009|p=53}} Along with his £70 scholarship from St John’s College, this was enough to live at Cambridge. There, Dirac pursued his interests in the theory of general relativity, an interest he had gained earlier as a student in Bristol, and in the nascent field of quantum physics, under the supervision of Ralph Fowler.{{harvnb|Farmelo|2009|pp=52–53}} From 1925 to 1928 he held an 1851 Research Fellowship from the Royal Commission for the Exhibition of 1851.1851 Royal Commission Archives He completed his PhD in June 1926 with the first thesis on quantum mechanics to be submitted anywhere.{{harvnb|Farmelo|2009|p=101}} He then continued his research in Copenhagen and Göttingen. In the spring of 1929, he was a visiting professor at the University of Wisconsin–Madison.BOOK, Kursunoglu, Behram N., Wigner, Eugene Paul, Paul Adrien Maurice Dirac: Reminiscences about a Great Physicist, 1990, Cambridge University Press, 0521386888, 132,books.google.com/books?id=1Pg7t9a_AX4C&q=paul+dirac+university+of+wisconsin+1929&pg=PA132, 30 September 2020, WEB, Paul Adrien Maurice Dirac,pages.hep.wisc.edu/~ldurand/715html/courseinfo/biographies/dirac.html, University of Wisconsin-Madison, 30 September 2020,

Family

File:Dirac,Paul 1963 Kopenhagen.jpg|thumb|Paul and Manci Dirac in CopenhagenCopenhagenIn 1937, Dirac married{{harvnb|Farmelo|2009|p=284}} Margit Wigner, a sister of physicist Eugene Wigner{{harvnb|Farmelo|2009|p=253}} and a divorcee.{{harvnb|Farmelo|2009|p=256}} Dirac raised Margit’s two children, Judith and Gabriel, as if they were his own.{{harvnb|Farmelo|2009|p=288}} Paul and Margit Dirac also had two daughters together, Mary Elizabeth and Florence Monica.{{harvnb|Farmelo|2009|pp=305, 323}}Margit, known as Manci, had visited her brother in 1934 in Princeton, New Jersey, from their native Hungary and, while at dinner at the Annex Restaurant, met the “lonely-looking man at the next table”. This account from a Korean physicist, Y. S. Kim, who met and was influenced by Dirac, also says: “It is quite fortunate for the physics community that Manci took good care of our respected Paul A. M. Dirac. Dirac published eleven papers during the period 1939–46. Dirac was able to maintain his normal research productivity only because Manci was in charge of everything else”.WEB,ysfine.com/dirac/wigsis.html, Wigner’s Sisters, Kim, Young Suh, 1995,web.archive.org/web/20080303112257/https://ysfine.com/dirac/wigsis.html, 3 March 2008,

Personality

Dirac was known among his colleagues for his precise and taciturn nature. His colleagues in Cambridge jokingly defined a unit called a “dirac”, which was one word per hour.{{harvnb|Farmelo|2009|p=89}} When Niels Bohr complained that he did not know how to finish a sentence in a scientific article he was writing, Dirac replied, “I was taught at school never to start a sentence without knowing the end of it.“WEB,www-history.mcs.st-and.ac.uk/Printonly/Dirac.html, Paul Adrien Maurice Dirac, University of St. Andrews, 4 April 2013, He criticised the physicist J. Robert Oppenheimer’s interest in poetry: “The aim of science is to make difficult things understandable in a simpler way; the aim of poetry is to state simple things in an incomprehensible way. The two are incompatible.“{{harvnb|Mehra|1972|pp=17–59}}Dirac himself wrote in his diary during his postgraduate years that he concentrated solely on his research, and stopped only on Sunday when he took long strolls alone.{{harvnb|Kragh|1990|p=17}}An anecdote recounted in a review of the 2009 biography tells of Werner Heisenberg and Dirac sailing on an ocean liner to a conference in Japan in August 1929. “Both still in their twenties, and unmarried, they made an odd couple. Heisenberg was a ladies’ man who constantly flirted and danced, while Dirac—’an Edwardian geek’, as biographer Graham Farmelo puts it—suffered agonies if forced into any kind of socializing or small talk. ‘Why do you dance?’ Dirac asked his companion. ‘When there are nice girls, it is a pleasure,’ Heisenberg replied. Dirac pondered this notion, then blurted out: ‘But, Heisenberg, how do you know beforehand that the girls are nice?{{’ “}}WEB,www.theguardian.com/books/2009/feb/01/strangest-man-paul-dirac-review, Anti-matter and madness, McKie, Rob, 1 February 2009, The Guardian, 4 April 2013, Margit Dirac told both George Gamow and Anton Capri in the 1960s that her husband had said to a house visitor, “Allow me to present Wigner’s sister, who is now my wife.“{{harvnb|Gamow|1966|p=121}}{{harvnb|Capri|2007|p=148}}Another story told of Dirac is that when he first met the young Richard Feynman at a conference, he said after a long silence, “I have an equation. Do you have one too?“{{harvnb|Zee|2010|p=105}}After he presented a lecture at a conference, one colleague raised his hand and said: “I don’t understand the equation on the top-right-hand corner of the blackboard”. After a long silence, the moderator asked Dirac if he wanted to answer the question, to which Dirac replied: “That was not a question, it was a comment.“NEWS,www.theglobeandmail.com/arts/books-and-media/review-the-strangest-man-by-graham-farmelo/article4289494/, A quantum leap into oddness, Chet, Raymo, The Globe and Mail, 17 October 2009, (Review of Farmelo’s The Strangest Man.){{harvnb|Farmelo|2009|pp=161–162}}, who attributes the story to Niels Bohr.Dirac was also noted for his personal modesty. He called the equation for the time evolution of a quantum-mechanical operator, which he was the first to write down, the “Heisenberg equation of motion”. Most physicists speak of Fermi–Dirac statistics for half-integer-spin particles and Bose–Einstein statistics for integer-spin particles. While lecturing later in life, Dirac always insisted on calling the former “Fermi statistics”. He referred to the latter as “Bose statistics” for reasons, he explained, of “symmetry”.BOOK, Mehra, Jagdish, Rechenberg, Helmut, Jagdish Mehra, Helmut Rechenberg, The Historical Development of Quantum Theory, 2001, Springer Science & Business Media, 9780387951805, 746,books.google.com/books?id=-pL56OcVubgC&q=Paul+Dirac+Einstein+statistics+Symmetry&pg=PA746,

Views on religion

Heisenberg recollected a conversation among young participants at the 1927 Solvay Conference about Einstein and Planck’s views on religion between Wolfgang Pauli, Heisenberg and Dirac. Dirac’s contribution was a criticism of the political purpose of religion, which Bohr regarded as quite lucid when hearing it from Heisenberg later.Pais, A., Niels Bohr’s Times: In Physics, Philosophy, and Polity (Oxford: Clarendon Press, 1991), p. 320. Among other things, Heisenberg imagined that Dirac might say:I don’t know why we are discussing religion. If we are honest—and scientists have to be—we must admit that religion is a jumble of false assertions, with no basis in reality. The very idea of God is a product of the human imagination. It is quite understandable why primitive people, who were so much more exposed to the overpowering forces of nature than we are today, should have personified these forces in fear and trembling. But nowadays, when we understand so many natural processes, we have no need for such solutions. I can’t for the life of me see how the postulate of an Almighty God helps us in any way. What I do see is that this assumption leads to such unproductive questions as to why God allows so much misery and injustice, the exploitation of the poor by the rich, and all the other horrors He might have prevented. If religion is still being taught, it is by no means because its ideas still convince us, but simply because some of us want to keep the lower classes quiet. Quiet people are much easier to govern than clamorous and dissatisfied ones. They are also much easier to exploit. Religion is a kind of opium that allows a nation to lull itself into wishful dreams and so forget the injustices that are being perpetrated against the people. Hence the close alliance between those two great political forces, the State and the Church. Both need the illusion that a kindly God rewards—in heaven if not on earth—all those who have not risen up against injustice, who have done their duty quietly and uncomplainingly. That is precisely why the honest assertion that God is a mere product of the human imagination is branded as the worst of all mortal sins.{{harvnb|Heisenberg|1971|pp=85–86}}Heisenberg’s view was tolerant. Pauli, raised as a Catholic, had kept silent after some initial remarks, but when finally he was asked for his opinion, said: “Well, our friend Dirac has got a religion and its guiding principle is ‘There is no God, and Paul Dirac is His prophet.{{’ “}} Everybody, including Dirac, burst into laughter.{{harvnb|Heisenberg|1971|p=87}}{{harvnb|Farmelo|2009|p=138}}, who says this was an old joke, pointing out a Punch footnote in the 1850s that “There is no God, and Harriet Martineau is her prophet.“Later in life, Dirac wrote an article mentioning God that appeared in the May 1963 edition of Scientific American, Dirac wrote:It seems to be one of the fundamental features of nature that fundamental physical laws are described in terms of a mathematical theory of great beauty and power, needing quite a high standard of mathematics for one to understand it. You may wonder: Why is nature constructed along these lines? One can only answer that our present knowledge seems to show that nature is so constructed. We simply have to accept it. One could perhaps describe the situation by saying that God is a mathematician of a very high order, and He used very advanced mathematics in constructing the universe. Our feeble attempts at mathematics enable us to understand a bit of the universe, and as we proceed to develop higher and higher mathematics we can hope to understand the universe better.WEB,blogs.scientificamerican.com/guest-blog/2010/06/25/the-evolution-of-the-physicists-picture-of-nature/, The Evolution of the Physicist’s Picture of Nature, Dirac, Paul, May 1963, Scientific American, 4 April 2013, In 1971, at a conference meeting, Dirac expressed his views on the existence of God.{{harvnb|Kragh|1990|pp=256–257}} Dirac explained that the existence of God could be justified only if an improbable event were to have taken place in the past:It could be that it is extremely difficult to start life. It might be that it is so difficult to start a life that it has happened only once among all the planets... Let us consider, just as a conjecture, that the chance of life starting when we have got suitable physical conditions is 10−100. I don’t have any logical reason for proposing this figure, I just want you to consider it as a possibility. Under those conditions ... it is almost certain that life would not have started. And I feel that under those conditions it will be necessary to assume the existence of a god to start off life. I would like, therefore, to set up this connection between the existence of a god and the physical laws: if physical laws are such that to start off life involves an excessively small chance so that it will not be reasonable to suppose that life would have started just by blind chance, then there must be a god, and such a god would probably be showing his influence in the quantum jumps which are taking place later on. On the other hand, if life can start very easily and does not need any divine influence, then I will say that there is no god.{{harvnb|Kragh|1990}}Dirac did not commit himself to any definite view, but he described the possibilities for scientifically answering the question of God.

Career

File:Solvay conference 1927.jpg|thumb|The 1927 Solvay Conference in Brussels, a gathering of the world’s top physicists. Dirac is in the centre of the middle row, seated behind Albert EinsteinAlbert EinsteinFile:DIAS_1942_photo.jpg|thumb|Dirac (front row 3rd from left), next to Éamon de Valera (front row 4th from left), Erwin Schrödinger (front row 2nd from right) at Dublin Institute for Advanced StudiesDublin Institute for Advanced StudiesDirac established the most general theory of quantum mechanics and discovered the relativistic equation for the electron, which now bears his name. The remarkable notion of an antiparticle to each fermion particle – e.g. the positron as antiparticle to the electron – stems from his equation. He was the first to develop quantum field theory, which underlies all theoretical work on sub-atomic or “elementary” particles today, work that is fundamental to our understanding of the forces of nature. He proposed and investigated the concept of a magnetic monopole, an object not yet known empirically, as a means of bringing even greater symmetry to James Clerk Maxwell’s equations of electromagnetism. He is credited as being the one to create quantum field theory, alongside creating quantum electrodynamics and coining the term. Dirac also coined the terms “fermion” and “boson”.{{harvnb|Farmelo|2009|pp=331}}Throughout his career, Dirac was motivated by the principles of mathematical beauty,WEB, Paul Dirac - Biography,mathshistory.st-andrews.ac.uk/Biographies/Dirac/, 31 December 2023, Maths History, en, with Peter Goddard stating that “Dirac cited mathematical beauty as the ultimate criterion for selecting the way forward in theoretical physics”.BOOK, Goddard, Peter,archive.org/details/isbn_0521583829, Paul Dirac: The Man and his Work, Cambridge University Press, 1998, 978-0521583824, x, en, Dirac was recognised for being mathematically gifted, as during his time in university, academics had affirmed that Dirac had an “ability of the highest order in mathematical physics”,{{harvnb|Farmelo|2009|pp=82}} with Ebenezer Cunningham stating that Dirac was “quite the most original student I have met in the subject of mathematical physics”.{{harvnb|Farmelo|2009|pp=76}} Therefore, Dirac was known for his “astounding physical intuition combined with the ability to invent new mathematics to create new physics”. During his career, Dirac made numerous important contributions to mathematical subjects, including the Dirac delta function, Dirac algebra and the Dirac operator.

Quantum theory

Dirac’s first step into a new quantum theory was taken late in September 1925. Ralph Fowler, his research supervisor, had received a proof copy of an exploratory paper by Werner Heisenberg in the framework of the old quantum theory of Bohr and Sommerfeld. Heisenberg leaned heavily on Bohr’s correspondence principle but changed the equations so that they involved directly observable quantities, leading to the matrix formulation of quantum mechanics. Fowler sent Heisenberg’s paper on to Dirac, who was on vacation in Bristol, asking him to look into this paper carefully.{{harvnb|Farmelo|2009|pp=83–88}}Dirac’s attention was drawn to a mysterious mathematical relationship, at first sight unintelligible, that Heisenberg had established. Several weeks later, back in Cambridge, Dirac suddenly recognised that this mathematical form had the same structure as the Poisson brackets that occur in the classical dynamics of particle motion. At the time, his memory of Poisson brackets was rather vague, but he found E. T. Whittaker’s Analytical Dynamics of Particles and Rigid Bodies illuminating.JOURNAL, Coutinho, S. C., 1 May 2014, Whittaker’s analytical dynamics: a biography,doi.org/10.1007/s00407-013-0133-1, Archive for History of Exact Sciences, en, 68, 3, 355–407, 10.1007/s00407-013-0133-1, 1432-0657, 122266762, From his new understanding, he developed a quantum theory based on non-commuting dynamical variables. This led him to the most profound and significant general formulation of quantum mechanics to date.NEWS, Paul Dirac: a genius in the history of physics,cerncourier.com/cws/article/cern/28693, Cern Courier, 13 May 2013, 15 August 2002, His novel formulation using Dirac brackets allowed him to obtain the quantisation rules in a novel and more illuminating manner. For this work,JOURNAL, On the Theory of Quantum Mechanics, Proceedings of the Royal Society A, 1926, Paul A. M., Dirac, Paul Dirac, 112, 762, 661–77, 94692, 10.1098/rspa.1926.0133, 1926RSPSA.112..661D, free, published in 1926, Dirac received a PhD from Cambridge. This formed the basis for Fermi–Dirac statistics that applies to systems consisting of many identical spin 1/2 particles (i.e. that obey the Pauli exclusion principle), e.g. electrons in solids and liquids, and importantly to the field of conduction in semi-conductors.Dirac was famously not bothered by issues of interpretation in quantum theory. In fact, in a paper published in a book in his honour, he wrote: “The interpretation of quantum mechanics has been dealt with by many authors, and I do not want to discuss it here. I want to deal with more fundamental things.“Dirac, “The inadequacies of quantum field theory”, in B. N. Kursunoglu & E. P. Wigner, eds., Paul Adrien Maurice Dirac (Cambridge: Cambridge University Press, 1987), p. 194. However, in 1964 he wrote a short article about the interpretation of quantum field theory when based on the Heisenberg picture of quantum theory; his primary point in the article was that the Schrodinger model does not work for this purpose.JOURNAL, Dirac, P. A. M., July 1964, Foundations of Quantum Mechanics,www.nature.com/articles/203115a0, Nature, en, 203, 4941, 115–116, 10.1038/203115a0, 1964Natur.203..115D, 34171325, 0028-0836,

The Dirac equation

{{further|Dirac equation}}In 1928, building on 2×2 spin matrices which he purported to have discovered independently of Wolfgang Pauli’s work on non-relativistic spin systems (Dirac told Abraham Pais, “I believe I got these [matrices] independently of Pauli and possibly Pauli got these independently of me.“),BOOK, Reminiscences about a Great Physicist, Cambridge University Press, 98, Behram N. KurÅŸunoÄŸlu, Eugene Paul Wigner, he proposed the Dirac equation as a relativistic equation of motion for the wave function of the electron.JOURNAL, Dirac, P. A. M., The Quantum Theory of the Electron, Proceedings of the Royal Society of London A, 1 February 1928, 117, 778, 610–24, 10.1098/rspa.1928.0023, 1928RSPSA.117..610D, free, This work led Dirac to predict the existence of the positron, the electron’s antiparticle, which he interpreted in terms of what came to be called the Dirac sea.{{Nobelprize}} with his Nobel Lecture, 12 December 1933 Theory of Electrons and Positrons The positron was observed by Carl Anderson in 1932. Dirac’s equation also contributed to explaining the origin of quantum spin as a relativistic phenomenon.The necessity of fermions (matter) being created and destroyed in Enrico Fermi’s 1934 theory of beta decay led to a reinterpretation of Dirac’s equation as a “classical” field equation for any point particle of spin ħ/2, itself subject to quantisation conditions involving anti-commutators. Thus reinterpreted, in 1934 by Werner Heisenberg, as a (quantum) field equation accurately describing all elementary matter particles – today quarks and leptons – this Dirac field equation is as central to theoretical physics as the Maxwell, Yang–Mills and Einstein field equations. Dirac is regarded as the founder of quantum electrodynamics, being the first to use that term. He also introduced the idea of vacuum polarisation in the early 1930s. This work was key to the development of quantum mechanics by the next generation of theorists, in particular Schwinger, Feynman, Sin-Itiro Tomonaga and Dyson in their formulation of quantum electrodynamics.Dirac’s The Principles of Quantum Mechanics, published in 1930, is a landmark in the history of science. It quickly became one of the standard textbooks on the subject and is still used today. In that book, Dirac incorporated the previous work of Werner Heisenberg on matrix mechanics and of Erwin Schrödinger on wave mechanics into a single mathematical formalism that associates measurable quantities to operators acting on the Hilbert space of vectors that describe the state of a physical system. The book also introduced the Dirac delta function. Following his 1939 article,JOURNAL, P. A. M. Dirac, 1939, A New Notation for Quantum Mechanics, Proceedings of the Cambridge Philosophical Society, 35, 3, 416, 10.1017/S0305004100021162, 1939PCPS...35..416D, 121466183, he also included the bra–ket notation in the third edition of his book,JOURNAL, Gieres, 10.1088/0034-4885/63/12/201, Mathematical surprises and Dirac’s formalism in quantum mechanics, 2000, 63, 12, 1893, Reports on Progress in Physics, quant-ph/9907069, 2000RPPh...63.1893G, 10854218, thereby contributing to its universal use nowadays.

Magnetic monopoles

In 1931, Dirac proposed that the existence of a single magnetic monopole in the universe would suffice to explain the quantisation of electrical charge.JOURNAL , free TITLE=MAGNETIC MONOPOLES DETECTED IN A REAL MAGNET FOR THE FIRST TIMEDATE=4 SEPTEMBER 2009 AUTHOR2=D.A. TENNANT AUTHOR4=B. KLEMKE AUTHOR6=R. MOESSNER AUTHOR8=M. MEISSNER AUTHOR10=J.-U. HOFFMANN AUTHOR12=S. GERISCHER AUTHOR14=R.S. PERRY DOI= 10.1126/SCIENCE.1178868 DATE=3 SEPTEMBER 2009 VOLUME=326 BIBCODE = 2009SCI...326..411M PAGES=411–4 AUTHOR2=S. R. GIBLIN AUTHOR4=R. ALDUS AUTHOR6=T. FENNELL, Naturepmid=19829376 volume=461 bibcode=2009Natur.461..956B pages=956–9Magnetic monopole#Searches for magnetic monopoles>Searches for magnetic monopoles).

Gravity

Dirac quantised the gravitational field. His work laid the foundations for canonical quantum gravity.THESIS, Schick, Michael, Canonical Quantum Gravity, 2021, Imperial College London,www.imperial.ac.uk/media/imperial-college/research-centres-and-groups/theoretical-physics/msc/dissertations/2021/Michael-Schick-Dissertation.pdf, In his 1959 lecture at the Lindau Meetings, Dirac discussed why gravitational waves have “physical significance”.WEB, Skuse, Ben, 1 September 2022, Black Holes - Topic {{!, Lindau Mediatheque |url=https://mediatheque.lindau-nobel.org/topics/black-holes |access-date=2 November 2023 |website=Lindau Nobel Mediatheque |language=en}} Dirac predicted gravitational waves would have well defined energy density in 1964.JOURNAL, Debnath, Lokenath, Lokenath Debnath, 2013, A short biography of Paul A. M. Dirac and historical development of Dirac delta function,www.tandfonline.com/doi/abs/10.1080/0020739X.2013.770091, International Journal of Mathematical Education in Science and Technology, en, 44, 8, 1201–1223, 10.1080/0020739X.2013.770091, 2013IJMES..44.1201D, 121423215, 0020-739X, Dirac reintroduced the term “graviton” in a number of lectures in 1959, noting that the energy of the gravitational field should come in quanta.{{harvnb|Farmelo|2009|pp=367–368}}JOURNAL, Debnath, Lokenath, 2013, A short biography of Paul A. M. Dirac and historical development of Dirac delta function,www.tandfonline.com/doi/abs/10.1080/0020739X.2013.770091, International Journal of Mathematical Education in Science and Technology, en, 44, 8, 1201–1223, 10.1080/0020739X.2013.770091, 2013IJMES..44.1201D, 121423215, 0020-739X,

String theory

Dirac is seen as having anticipated string theory, with his work on the Dirac membrane and Dirac–Born–Infeld action, amongst other contributions.{{harvnb|Kragh|1990|p=198, 348}}JOURNAL, Sanyuk, Valerii I., Sukhanov, Alexander D., 1 September 2003, Dirac in 20th century physics: a centenary assessment,ufn.ru/en/articles/2003/9/c/, Physics-Uspekhi, en, 46, 9, 937–956, 10.1070/PU2003v046n09ABEH001165, 250754932, 1063-7869, He also developed a general theory of the quantum field with dynamical constraints,JOURNAL, Dirac, P. A. M., 1950, Generalized Hamiltonian Dynamics, Canadian Journal of Mathematics, en, 2, 129–148, 10.4153/CJM-1950-012-1, 0008-414X, free, JOURNAL, Dirac, P. A. M., 1951, The Hamiltonian Form of Field Dynamics, Canadian Journal of Mathematics, en, 3, 1–23, 10.4153/CJM-1951-001-2, 0008-414X, free, which forms the basis of the gauge theories and superstring theories of today.Misha, S., Quantum Field Theory II (Singapore: World Scientific, 2019), p. 287.

University of Cambridge

Dirac was the Lucasian Professor of Mathematics at the University of Cambridge from 1932 to 1969. He conceived the Helikon vortex isotope separation process in 1934.{{Citation |last=Kaufmann |first=André |title=Useful Applications of the RHVT |date=2022 |url=https://doi.org/10.1007/978-3-030-89766-6_6 |work=The Ranque Hilsch Vortex Tube Demystified: Understanding the Working Principles of the Vortex Tube |pages=69 |editor-last=Kaufmann |editor-first=André |access-date=11 January 2024 |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-030-89766-6_6 |isbn=978-3-030-89766-6}}{{harvnb|Farmelo|2009|pp=248–249}} quote=During a visit to Cambridge in May 1934, Wigner saw the apparatus and asked Dirac questions about it, In 1937, he proposed a speculative cosmological model based on the large numbers hypothesis. During World War II, he conducted important theoretical work on uranium enrichment by gas centrifuge.Kemp, R. S., “Gas Centrifuge Theory and Development: A Review of US Programs”, Science and Global Security, June 2009. He introduced the separative work unit (SWU) in 1941.ARXIV, 0906.2505, physics.hist-ph, Jeremy, Bernstein, SWU for You and Me, 13 June 2009, He contributed to the Tube Alloys project, the British programme to research and construct atomic bombs during World War II.ODNB, Cathcart, Brian, 25 May 2006, Tube Alloys directorate (act. 1941–1945),www.oxforddnb.com/display/10.1093/ref:odnb/9780198614128.001.0001/odnb-9780198614128-e-93791, 25 October 2023, en, 10.1093/ref:odnb/93791, Dirac’s quantum electrodynamics (QED) made predictions that were – more often than not – infinite and therefore unacceptable. A workaround known as renormalisation was developed, but Dirac never accepted this. “I must say that I am very dissatisfied with the situation”, he said in 1975, “because this so-called ‘good theory’ does involve neglecting infinities which appear in its equations, neglecting them in an arbitrary way. This is just not sensible mathematics. Sensible mathematics involves neglecting a quantity when it is small – not neglecting it just because it is infinitely great and you do not want it!“{{harvnb|Kragh|1990|p=184}} His refusal to accept renormalisation resulted in his work on the subject moving increasingly out of the mainstream.However, from his once rejected notes he managed to work on putting quantum electrodynamics on “logical foundations” based on Hamiltonian formalism that he formulated. He found a rather novel way of deriving the anomalous magnetic moment “Schwinger term” and also the Lamb shift, afresh in 1963, using the Heisenberg picture and without using the joining method used by Weisskopf and French, and by the two pioneers of modern QED, Schwinger and Feynman. That was two years before the Tomonaga–Schwinger–Feynman QED was given formal recognition by an award of the Nobel Prize for physics.Weisskopf and French (FW) were the first to obtain the correct result for the Lamb shift and the anomalous magnetic moment of the electron. At first FW results did not agree with the incorrect but independent results of Feynman and Schwinger.{{harvnb|Schweber|1994}} The 1963–1964 lectures Dirac gave on quantum field theory at Yeshiva University were published in 1966 as the Belfer Graduate School of Science, Monograph Series Number, 3.

Florida State University and University of Miami

(File:Paul Dirac Bust at FSU.jpg|thumb|upright|A bust of Paul Dirac at Florida State University)After having relocated to Florida to be near his elder daughter, Mary, Dirac spent his last fourteen years of both life and physics research at the University of Miami in Coral Gables, Florida, and Florida State University in Tallahassee, Florida.In the 1950s in his search for a better QED, Paul Dirac developed the Hamiltonian theory of constraintsCanadian Journal of Mathematics, 1950, vol 2, 129; 1951, vol 3, 1. based on lectures that he delivered at the 1949 International Mathematical Congress in Canada. Dirac1951 “The Hamiltonian Form of Field Dynamics” Canad Jour Math, vol 3, 1 had also solved the problem of putting the Schwinger–Tomonaga equation into the Schrödinger representationPhillips R. J. N. 1987 Tributes to Dirac p31 London: Adam Hilger and given explicit expressions for the scalar meson field (spin zero pion or pseudoscalar meson), the vector meson field (spin one rho meson), and the electromagnetic field (spin one massless boson, photon).The Hamiltonian of constrained systems is one of Dirac’s many masterpieces. It is a powerful generalisation of Hamiltonian theory that remains valid for curved spacetime. The equations for the Hamiltonian involve only six degrees of freedom described by g_{rs},p^{rs} for each point of the surface on which the state is considered. The g_{m0} (m = 0, 1, 2, 3) appear in the theory only through the variables g^{r0}, ( -{g^{00}} ) ^{-1/2} which occur as arbitrary coefficients in the equations of motion.There are four constraints or weak equations for each point of the surface x^0 = constant. Three of them H_r form the four vector density in the surface. The fourth H_L is a 3-dimensional scalar density in the surface HL ≈ 0; Hr ≈ 0 (r = 1, 2, 3)In the late 1950s, he applied the Hamiltonian methods he had developed to cast Einstein’s general relativity in Hamiltonian formProc Roy Soc 1958, A vol 246, 333JOURNAL, Dirac, P. A. M., Fixation of Coordinates in the Hamiltonian Theory of Gravitation, Physical Review, 1 May 1959, 114, 3, 924, 10.1103/PhysRev.114.924, 1959PhRv..114..924D,journals.aps.org/pr/abstract/10.1103/PhysRev.114.924, 16 October 2020, and to bring to a technical completion the quantisation problem of gravitation and bring it also closer to the rest of physics according to Salam and DeWitt. In 1959 he also gave an invited talk on “Energy of the Gravitational Field” at the New York Meeting of the American Physical Society.Dirac, P. A. M., “Energy of the Gravitational Field”, Physical Review Letters, Vol. 2, Nr. 8, 20 March 1959, pp. 368–371. In 1964 he published his Lectures on Quantum Mechanics (London: Academic) which deals with constrained dynamics of nonlinear dynamical systems including quantisation of curved spacetime. He also published a paper entitled “Quantization of the Gravitational Field” in the 1967 ICTP/IAEA Trieste Symposium on Contemporary Physics.From September 1970 to January 1971, Dirac was a visiting professor at Florida State University in Tallahassee. During that time he was offered a permanent position there, which he accepted, becoming a full professor in 1972. Contemporary accounts of his time there describe it as happy except that he apparently found the summer heat oppressive and liked to escape from it to Cambridge.WEB,www.famousscientists.org/paul-dirac/, Paul Dirac, Famous Scientists, 13 October 2021, He would walk about a mile to work each day and was fond of swimming in one of the two nearby lakes (Silver Lake and Lost Lake), and was also more sociable than he had been at the University of Cambridge, where he mostly worked at home apart from giving classes and seminars. At Florida State, he would usually eat lunch with his colleagues before taking a nap.BOOK, Pais, Abraham,books.google.com/books?id=Hm22wB0wGFcC, Paul Dirac: The Man and His Work, 27, 2009, Cambridge University Press, 978-0-511-56431-4, 958553083, Google Books, Dirac published over 60 papers in those last twelve years of his life, including a short book on general relativity.Baer, H. A., & Belyaev, A., eds., Proceedings of the Dirac Centennial Symposium (Singapore: World Scientific, 2003), p. 3. His last paper (1984), entitled “The inadequacies of quantum field theory,” contains his final judgment on quantum field theory: “These rules of renormalisation give surprisingly, excessively good agreement with experiments. Most physicists say that these working rules are, therefore, correct. I feel that is not an adequate reason. Just because the results happen to be in agreement with observation does not prove that one’s theory is correct.” The paper ends with the words: “I have spent many years searching for a Hamiltonian to bring into the theory and have not yet found it. I shall continue to work on it as long as I can and other people, I hope, will follow along such lines.“BOOK, Pais, Abraham,books.google.com/books?id=Hm22wB0wGFcC, Paul Dirac: The Man and His Work, 28, 2009, Cambridge University Press, 978-0-511-56431-4, 958553083, Google Books,

Students

Amongst his many students{{MathGenealogy|id=18524}}{{MacTutor Biography|id=Dirac}} were Homi J. Bhabha, Fred Hoyle, John Polkinghorne and Freeman Dyson.Sandberg, L., “Freeman J. Dyson (1923–2020), Scientist and Writer, Who Dreamt Among the Stars, Dies at 96”, IAS, 28 February 2020. Polkinghorne recalls that Dirac “was once asked what was his fundamental belief. He strode to a blackboard and wrote that the laws of nature should be expressed in beautiful equations.“John Polkinghorne. ‘Belief in God in an Age of Science’ p 2

Honours

Dirac shared the 1933 Nobel Prize for physics with Erwin Schrödinger “for the discovery of new productive forms of atomic theory”. Dirac was also awarded the Royal Medal in 1939 and both the Copley Medal and the Max Planck Medal in 1952. He was elected a Fellow of the Royal Society in 1930,WEB,www.nobelprize.org/nobel_prizes/physics/laureates/1933/dirac-bio.html, Nobel Bio, Nobel Foundation, 27 January 2014, a member of the American Philosophical Society in 1938,WEB, APS Member History,search.amphilsoc.org/memhist/search?creator=Paul+Dirac&title=&subject=&subdiv=&mem=&year=&year-max=&dead=&keyword=&smode=advanced, 16 May 2023, search.amphilsoc.org, an Honorary Fellow of the American Physical Society in 1948, a member of the United States National Academy of Sciences in 1949,WEB, Paul A. Dirac,www.nasonline.org/member-directory/deceased-members/46802.html, 16 May 2023, www.nasonline.org, a member of the American Academy of Arts and Sciences in 1950,WEB, 9 February 2023, Paul Adrien Maurice Dirac,www.amacad.org/person/paul-adrien-maurice-dirac, 16 May 2023, American Academy of Arts & Sciences, en, and an Honorary Fellow of the Institute of Physics, London in 1971. He received the inaugural J. Robert Oppenheimer Memorial Prize in 1969.BOOK, Winners, the blue ribbon encyclopedia of awards,archive.org/details/winnersblueribbo0000walt, registration, Walter, Claire, 1982, 438, Facts on File Inc., 9780871963864, JOURNAL, Dirac Receives Miami Center Oppenheimer Memorial Prize, Physics Today, 22, 4, April 1969, 127, 10.1063/1.3035512, Dirac became a member of the Order of Merit in 1973, having previously turned down a knighthood as he did not want to be addressed by his first name.{{harvnb|Farmelo|2009|pp=403–404}}

Death

File:Nima visits dirac.jpg|thumb|The tombstone of Dirac and his wife in Roselawn Cemetery, Tallahassee, FloridaTallahassee, FloridaFile:Dirac’s commemorative marker.jpg|thumb|The commemorative marker in Westminster AbbeyWestminster AbbeyIn 1984, Dirac died in Tallahassee, Florida, and was buried at Tallahassee’s Roselawn Cemetery.WEB,www.fsu.edu/~fstime/FS-Times/Volume1/Issue1/Dirac.html, Dirac takes his place next to Isaac Newton, Florida State University, 4 April 2013, dead,www.fsu.edu/~fstime/FS-Times/Volume1/Issue1/Dirac.html," title="web.archive.org/web/19970427191316www.fsu.edu/~fstime/FS-Times/Volume1/Issue1/Dirac.html,">web.archive.org/web/19970427191316www.fsu.edu/~fstime/FS-Times/Volume1/Issue1/Dirac.html, 27 April 1997, Dirac’s childhood home in Bishopston, Bristol is commemorated with a blue plaque,Fells, M., Bristol Plaques (Cheltenham: The History Press, 2016), p. 40. and the nearby Dirac Road is named in recognition of his links with the city of Bristol. A commemorative stone was erected in a garden in Saint-Maurice, Switzerland, the town of origin of his father’s family, on 1 August 1991. On 13 November 1995 a commemorative marker, made from Burlington green slate and inscribed with the Dirac equation, was unveiled in Westminster Abbey.WEB,www.dirac.ch/PaulDirac.html, Paul Dirac, Gisela Dirac, 4 April 2013, The Dean of Westminster, Edward Carpenter, had initially refused permission for the memorial, thinking Dirac to be anti-Christian, but was eventually (over a five-year period) persuaded to relent.{{harvnb|Farmelo|2009|pp=414–415}}.

Legacy

The influence and importance of Dirac’s work have increased with the decades, and physicists use daily the concepts and equations that he developed.In 1975, Dirac gave a series of five lectures at the University of New South Wales which were subsequently published as a book, Directions in Physics (1978). He donated the royalties from this book to the university for the establishment of Dirac Lecture Series. The Silver Dirac Medal for the Advancement of Theoretical Physics is awarded by the University of New South Wales to commemorate the lecture.WEB,www.phys.unsw.edu.au/ANNUAL_REPORTS/2004/school7.html, Dirac Medal awards, University of New South Wales, 4 April 2013, dead,www.phys.unsw.edu.au/ANNUAL_REPORTS/2004/school7.html," title="web.archive.org/web/20130412032421www.phys.unsw.edu.au/ANNUAL_REPORTS/2004/school7.html,">web.archive.org/web/20130412032421www.phys.unsw.edu.au/ANNUAL_REPORTS/2004/school7.html, 12 April 2013, Immediately after his death, two organisations of professional physicists established annual awards in Dirac’s memory. The Institute of Physics, the United Kingdom’s professional body for physicists, awards the Paul Dirac Medal for “outstanding contributions to theoretical (including mathematical and computational) physics”.WEB,www.iop.org/about/awards/gold/dirac/page_38427.html, The Dirac Medal, Institute of Physics, 24 November 2007, The first three recipients were Stephen Hawking (1987), John Stewart Bell (1988), and Roger Penrose (1989). Since 1985, the International Centre for Theoretical Physics awards the Dirac Medal of the ICTP each year on Dirac’s birthday (8 August).WEB,www.ictp.it/about-ictp/prizes-awards/the-dirac-medal.aspx, The Dirac Medal, International Centre for Theoretical Physics, 4 April 2013, The Dirac-Hellman Award at Florida State University was endowed by Bruce P. Hellman in 1997 to reward outstanding work in theoretical physics by FSU researchers.WEB,www.physics.fsu.edu/undergrads/UndergraduateAwards.htm, Undergraduate Awards, Florida State University, 4 April 2013, dead,www.physics.fsu.edu/undergrads/UndergraduateAwards.htm," title="web.archive.org/web/20130412191942www.physics.fsu.edu/undergrads/UndergraduateAwards.htm,">web.archive.org/web/20130412191942www.physics.fsu.edu/undergrads/UndergraduateAwards.htm, 12 April 2013, The Paul A.M. Dirac Science Library at Florida State University, which Manci opened in December 1989,WEB, Remodelled Dirac Science Library Opened at FSU,grahamfarmelo.com/remodelled-dirac-science-library-formally-opened-at-fsu/, Graham Farmelo, 12 October 2015, 22 February 2015, is named in his honour, and his papers are held there.WEB,purl.fcla.edu/fsu/MSS_1989-009, Paul A.M. Dirac Papers, Florida State University, 18 March 2021, Outside is a statue of him by Gabriella Bollobás.{{harvnb|Farmelo|2009|p=417}} The street on which the National High Magnetic Field Laboratory in Innovation Park of Tallahassee, Florida, is located is named Paul Dirac Drive. As well as in his hometown of Bristol, there is also a road named after him, Dirac Place, in Didcot, Oxfordshire.WEB,goo.gl/maps/72dU5yFjwBz, Dirac Place, Didcot OX11 8TL, Google Maps, The Dirac-Higgs Science Centre in Bristol is also named in his honour.weblinkThe BBC named a video codec, Dirac, in his honour. An asteroid discovered in 1983 was named after Dirac.WEB,ssd.jpl.nasa.gov/sbdb.cgi?sstr=5997+Dirac, 5997 Dirac (1983 TH), Jet Propulsion Laboratory, 9 January 2015, The Distributed Research utilising Advanced Computing (DiRAC) and Dirac software are named in his honour.

Publications

• The Principles of Quantum Mechanics (1930): This book summarises the ideas of quantum mechanics using the modern formalism that was largely developed by Dirac himself. Towards the end of the book, he also discusses the relativistic theory of the electron (the Dirac equation), which was also pioneered by him. This work does not refer to any other writings then available on quantum mechanics.
• Lectures on Quantum Mechanics (1966): Much of this book deals with quantum mechanics in curved space-time.
• Lectures on Quantum Field Theory (1966): This book lays down the foundations of quantum field theory using the Hamiltonian formalism.
• Spinors in Hilbert Space (1974): This book based on lectures given in 1969 at the University of Miami deals with the basic aspects of spinors starting with a real Hilbert space formalism. Dirac concludes with the prophetic words “We have boson variables appearing automatically in a theory that starts with only fermion variables, provided the number of fermion variables is infinite. There must be such boson variables connected with electrons...”
• General Theory of Relativity (1975): This 69-page work summarises Einstein’s general theory of relativity.

References

Citations

{{Reflist}}

General sources

• BOOK, Capri, Anton Z., 2007, Quips, Quotes, and Quanta: An Anecdotal History of Physics, World Scientific, Hackensack, New Jersey, 978-981-270-919-6,books.google.com/books?id=GfmR0mHxeZkC&pg=PA148, 214286147,
• BOOK, Crease, Robert P., Robert P. Crease, Mann, Charles C., Charles C. Mann, 1986, The Second Creation: Makers of the Revolution in Twentieth Century Physics, Macmillan Publishing, New York City, 978-0-02-521440-8, 13008048,archive.org/details/secondcreationma00crea,
• BOOK, Farmelo, Graham, Graham Farmelo, 2009, (The Strangest Man, The Strangest Man: The Hidden Life of Paul Dirac, Quantum Genius), London, Faber and Faber, 978-0-571-22278-0, [Published in the United States as The Strangest Man: The Hidden Life of Paul Dirac, Mystic of the Atom. {{isbn|978-0-465-01827-7}}.]
• BOOK, Gamow, George, George Gamow, 1966, Thirty Years That Shook Physics: The Story of Quantum Theory, Doubleday, Garden City, New York, 978-0-486-24895-0,books.google.com/books?id=L90_wY1VCW0C&pg=PA121, 11970045,
• BOOK, Heisenberg, Werner, Werner Heisenberg, Physics and Beyond: Encounters and Conversations, Harper & Row, New York City, 978-0-06-131622-7, 1971, 115992,archive.org/details/physicsbeyondenc00heis,
• BOOK, Kragh, Helge, Helge Kragh, Dirac: A Scientific Biography, 1990, Cambridge University Press, Cambridge, 978-0-521-38089-8, 20013981,archive.org/details/diracscientificb0000krag, registration,
• BOOK, Mehra, Jagdish, Jagdish Mehra, The Golden Age of Theoretical Physics: P. A. M. Dirac’s Scientific Works from 1924–1933, Wigner, Eugene Paul, Eugene Wigner, Salam, Abdus, Abdus Salam, 1972, Aspects of Quantum Theory, 17–59, University Press, Cambridge, 978-0-521-08600-4, 532357,
• BOOK, Schweber, Silvan S., Silvan S. Schweber, QED and the men who made it: Dyson, Feynman, Schwinger, and Tomonaga,archive.org/details/qedmenwhomadeitd0000schw, registration, Princeton University Press, Princeton, New Jersey, 1994, 978-0-691-03685-4, 28966591,
• BOOK, Zee, Anthony, Anthony Zee, Quantum Field Theory in a Nutshell,archive.org/details/isbn_9780691140346, registration, Princeton University Press, Princeton, New Jersey, 2010, 318585662, 978-1-4008-3532-4,

Further reading

• NEWS, Brown, Helen, The Strangest Man: The Hidden Life of Paul Dirac by Graham Farmelo – review &91;print version: The man behind the maths&93;,www.telegraph.co.uk/culture/books/bookreviews/4316309/The-Strangest-Man-the-Hidden-Life-of-Paul-Dirac-by-Graham-Farmelo---review.html,www.telegraph.co.uk/culture/books/bookreviews/4316309/The-Strangest-Man-the-Hidden-Life-of-Paul-Dirac-by-Graham-Farmelo---review.html," title="web.archive.org/web/20090202082203www.telegraph.co.uk/culture/books/bookreviews/4316309/The-Strangest-Man-the-Hidden-Life-of-Paul-Dirac-by-Graham-Farmelo---review.html,">web.archive.org/web/20090202082203www.telegraph.co.uk/culture/books/bookreviews/4316309/The-Strangest-Man-the-Hidden-Life-of-Paul-Dirac-by-Graham-Farmelo---review.html, dead, 2 February 2009, The Daily Telegraph (Review), 24 January 2009, 20, 11 April 2011, .
• NEWS, Gilder, Louisa, Quantum Leap – Review of ‘The Strangest Man: The Hidden Life of Paul Dirac by Graham Farmelo’,www.nytimes.com/2009/09/13/books/review/Gilder-t.html, The New York Times, 13 September 2009, 11 April 2011, Review.
• Mukunda, N. (1987) “The life and work of P.A.M. Dirac”, pages 260 to 282 in Recent Developments in Theoretical Physics, World Scientific {{mr|id=935624}}

External links

{{Commons and category|Paul Dirac}}

• Oral history interview transcript with P. A. M. Dirac on 1 April 1962, American Institute of Physics, Niels Bohr Library & Archives - Session I
• Oral history interview transcript with P. A. M. Dirac on 6 May 1963, American Institute of Physics, Niels Bohr Library & Archives - Session II
• Oral history interview transcript with P. A. M. Dirac on 7 Mary 1963, American Institute of Physics, Niels Bohr Library & Archives - Session III
• Oral history interview transcript with P. A. M. Dirac on 10 May 1963, American Institute of Physics, Niels Bohr Library & Archives - Session IV
• Oral history interview transcript with P. A. M. Dirac on 14 May 1963, American Institute of Physics, Niels Bohr Library & Archives - V
• Free online access to Dirac’s classic 1920s papers from Royal Society’s Proceedings A
• alsos.wlu.edu/qsearch.aspx?browse=people%2FDirac%2C+Paul" title="web.archive.org/web/20190502044245alsos.wlu.edu/qsearch.aspx?browse=people%2FDirac%2C+Paul">Annotated bibliography for Paul Dirac from the Alsos Digital Library for Nuclear Issues
• The Paul Dirac Collection at Florida State University
• The Papers of Professor Paul Dirac at Churchill Archives Centre

{{Copley Medallists 1951-2000}}{{Nobel Prize in Physics Laureates 1926-1950}}{{1933 Nobel Prize winners}}{{Lucasian Professors of Mathematics}}{{Authority control}}