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John Clauser

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John Clauser
John Clauser in 2024
Born
John Francis Clauser

(1942-12-01) December 1, 1942 (age 81)
Pasadena, California, U.S.
Education
Known forBell test experiments, CHSH inequality
Awards
Scientific career
FieldsQuantum mechanics
Institutions
ThesisMeasurement of the Cosmic Microwave Background by Optical Observations of Interstellar Molecules (1970)
Doctoral advisorPatrick Thaddeus
Websitejohnclauser.com

John Francis Clauser (/ˈklaʊzər/; born December 1, 1942) is an American theoretical and experimental physicist known for contributions to the foundations of quantum mechanics, in particular the Clauser–Horne–Shimony–Holt inequality.[1] Clauser was awarded the 2022 Nobel Prize in Physics, jointly with Alain Aspect and Anton Zeilinger "for experiments with entangled photons, establishing the violation of Bell inequalities and pioneering quantum information science".[2]

Early life

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Clauser was born in Pasadena, California. His father, Francis H. Clauser, was a professor of aeronautical engineering who founded and chaired the aeronautics department at Johns Hopkins University. He later served as the Clark Blanchard Millikan Professor of Engineering at the California Institute of Technology (Caltech).[3] His mother, Catharine McMillan, was the humanities librarian at Caltech and sister of 1951 Nobel Prize in Chemistry laureate Edwin McMillan.[4]

He received a Bachelor of Science in physics from Caltech in 1964, where he was a member of Dabney House.[5] He received a Master of Arts in physics in 1966 and a Doctor of Philosophy in physics in 1969 from Columbia University[1] under the direction of Patrick Thaddeus.[6][7]

Career

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From 1969 to 1975, he worked as a postdoctoral researcher at the University of California, Berkeley and Lawrence Berkeley National Laboratory. In 1972, working with Berkeley graduate student Stuart Freedman, he carried out the first experimental test of the CHSH-Bell's theorem predictions. This was the first experimental observation of a violation of a Bell inequality.[1][8] In 1974, working with Michael Horne, he first showed that a generalization of Bell's Theorem provides severe constraints for all local realistic theories of nature (a.k.a. objective local theories). That work introduced the Clauser–Horne (CH) inequality as the first fully general experimental requirement set by local realism. It also introduced the "CH no-enhancement assumption", whereupon the CH inequality reduces to the CHSH inequality, and whereupon associated experimental tests also constrain local realism. Also in 1974 he made the first observation of sub-Poissonian statistics for light (via a violation of the Cauchy–Schwarz inequality for classical electromagnetic fields), and thereby, for the first time, demonstrated an unambiguous particle-like character for photons.[citation needed]

Starting in 1973, Clauser published the newsletter Epistemological Letters, which was created because mainstream academic journals were relunctant to publish articles about the philosophy of quantum mechanics.[citation needed] Clauser worked as a research physicist mainly at Lawrence Livermore and Berkeley from 1975 to 1997. In 1976 he carried out the world's second experimental test of the CHSH-Bell's Theorem predictions.[9]

Clauser was awarded the Wolf Prize in Physics in 2010 together with Alain Aspect and Anton Zeilinger. The three were also jointly awarded the 2022 Nobel Prize in Physics.[10]

Climate change denial

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In May 2023, Clauser joined the board of the CO2 Coalition, a climate change denial organization.[11] Later that year, Clauser called himself a "climate denier" and claimed "there is no climate crisis".[12] Clauser has never published a peer-reviewed article on the climate, and his views on climate change have been described as "pseudoscience".[12] His belief that cloud cover has more of an impact on Earth's temperature than carbon dioxide emissions is contradicted by the overwhelming scientific consensus on climate change.[12][13][14] Observational evidence shows the overall current cloud feedback amplifies global warming and does not have a cooling effect.[15]

Personal life

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Clauser is an atheist. He has emphysema due to smoking cigarettes in his youth.[12]

References

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  1. ^ a b c "John F. Clauser". American Institute of Physics.
  2. ^ "The Nobel Prize in Physics 2022". The Royal Swedish Academy of Sciences (Press release). October 4, 2022.
  3. ^ "Proving that Quantum Entanglement is Real". California Institute of Technology. September 20, 2022. Retrieved October 6, 2022.
  4. ^ "Caltech Alum Wins Nobel Prize in Physics". California Institute of Technology. October 4, 2022. Retrieved October 6, 2022.
  5. ^ The Big T. Associated Students of the California Institute of Technology. 1963.
  6. ^ Clauser, John F. (1970). Measurement of the Cosmic Microwave Background by Optical Observations of Interstellar Molecules (Ph.D. thesis). Columbia University. OCLC 145659. ProQuest 302516464.
  7. ^ "Patrick Thaddeus (1932–2017)" (PDF). Biographical Memoirs. National Academy of Sciences. p. 12.
  8. ^ Freedman, Stuart J.; Clauser, John F. (April 3, 1972). "Experimental Test of Local Hidden-Variable Theories". Physical Review Letters. 28 (14): 938-941. Bibcode:1972PhRvL..28..938F. doi:10.1103/PhysRevLett.28.938.
  9. ^ "Proving that Quantum Entanglement is Real". California Institute of Technology. September 20, 2022. Retrieved October 6, 2022.
  10. ^ "The Nobel Prize in Physics 2022". NobelPrize.org. Retrieved October 4, 2022.
  11. ^ Cho, Seunghan (June 26, 2023). "노벨물리학상 수상자 "정치인들, 잘못된 과학정보 만들어내"" [Nobel laureate in physics "Politicians create false scientific information"]. The Korea Economic Daily (in Korean). Yonhap News Agency. Retrieved July 28, 2023.
  12. ^ a b c d Joselow, Maxine (November 16, 2023). "He won a Nobel Prize. Then he started denying climate change". The Washington Post. ISSN 0190-8286. Archived from the original on November 18, 2023. Retrieved November 17, 2023.
  13. ^ Oreskes, Naomi (December 3, 2004). "The Scientific Consensus on Climate Change". Science. 306 (5702): 1686. doi:10.1126/science.1103618.
  14. ^ Graham, Steve (March 1, 1999). "Clouds & Radiation". NASA Earth Observatory. Archived from the original on November 19, 2023. Retrieved November 19, 2023.
  15. ^ Ceppi, Paulo; Nowack, Peer (July 19, 2021). Held, Isaac M. (ed.). "Observational evidence that cloud feedback amplifies global warming". PNAS. 118 (30). Bibcode:2021PNAS..11826290C. doi:10.1073/pnas.2026290118. PMC 8325336.
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