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]
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][15] Observational evidence shows the overall current cloud feedback amplifies global warming and does not have a cooling effect.[16]
Personal life
Clauser is an atheist. He has emphysema due to smoking cigarettes in his youth.[12]
^The Big T. Associated Students of the California Institute of Technology. 1963.
^Clauser, John F. (1970). Measurement of the Cosmic Microwave Background by Optical Observations of Interstellar Molecules (Ph.D. thesis). Columbia University. OCLC145659. ProQuest302516464.
