Alain Jean Aspect (; born 15 June 1947) is a French physicist noted for his experimental work on quantum entanglement. Aspect's experiment (19801982) bears his name.
Aspect was awarded the 2022 Nobel Prize in Physics, jointly with John Clauser and Anton Zeilinger, "for experiments with entangled photons, establishing the violation of Bell inequalities and pioneering quantum information science".
In 2025 he was elected to the Académie Française.
Education Aspect is a graduate of the École Normale Supérieure de Cachan (ENS Cachan, today part of Paris-Saclay University). He passed the agrégation in physics in 1969 and received his PhD degree in 1971 from the École supérieure d'optique (later known as Institut d'Optique Graduate School) of Université d'Orsay (later known as Université Paris-Sud). He then taught for three years in Cameroon as a replacement for then compulsory military service.
In the early 1980s, while working on his doctorat d'État (habilitation thesis), he performed the Bell test experiments that showed that Albert Einstein, Boris Podolsky and Nathan Rosen's putative reductio ad absurdum of quantum mechanics, namely that it implied 'ghostly action at a distance', did in fact appear to be realized when two particles were separated by an arbitrarily large distance (see EPR paradox and Aspect's experiment). A correlation between the particles' wave functions remains, as long as they were once part of the same undisturbed wave function before one of the child particles was measured. He defended his doctorat d'État in 1983 at Université Paris-Sud (today part of Paris-Saclay University).
Aspect received an honorary doctorate from Heriot-Watt University in 2008.
Research
Aspect's experiments, following the first experiment of Stuart Freedman and John Clauser in 1972, were considered to provide further support to the thesis that Bell's inequalities are violated in its CHSH version, in particular by closing a form of the locality loophole. However, his results were not completely conclusive since there were loopholes that allowed for alternative explanations that comply with local realism.
After his work on Bell's inequalities, Aspect turned toward studies of laser cooling of neutral atoms, and Bose–Einstein condensates at the Kastler-Brossel Laboratory.
Aspect was deputy director of the French "grande école" École supérieure d'optique until 1994. He is a member of the French Academy of Sciences and French Academy of Technologies, and a professor at the École polytechnique.
Distinctions Aspect was elected a Foreign Member of the Royal Society (ForMemRS) in 2015. His certificate of election reads:
In 2005 he was awarded the gold medal of the Centre national de la recherche scientifique, where he is Research Director. The 2010 Wolf Prize in physics was awarded to Aspect, Anton Zeilinger and John Clauser. In 2013 Aspect was awarded both the Niels Bohr International Gold Medal and the UNESCO Niels Bohr Medal. In 2011, he was assigned the Medal of the City of Paris. In 2013, he was also awarded the Balzan Prize for Quantum Information Processing and Communication. In 2014, he was named Officer of the Legion of Honour.
Asteroid 33163 Alainaspect, discovered by astronomers at Caussols in 1998, was named after him. The official was published by the Minor Planet Center on 8 November 2019 ().
Aspect was awarded the 2022 Nobel Prize in Physics alongside John F. Clauser and Anton Zeilinger "for experiments with entangled photons, establishing the violation of Bell's inequalities and pioneering quantum information science".
On 26 June 2025, he was elected to the Académie Française.
Honours and awards Accolades received by Aspect include the following:
Honours 2025: Elected to the Académie Française. 2022: Commander of the Legion of Honour. 2014: Officier of the Legion of Honour. 2011: Commander of the Palmes académiques. 2011: Medal of the City of Paris. 2010: Officier of the National Order of Merit. 2005: Knight of the Legion of Honour.
Awards
2022: Nobel Prize in Physics (with John Clauser and Anton Zeilinger) 2022: Honorary Optica Member 2013: Balzan Prize 2013: Niels Bohr International Gold Medal 2013: UNESCO Niels Bohr Medal 2013: Frederic Ives Medal/Jarus W. Quinn Prize 2012: Albert Einstein Medal 2012: Herbert Walther Award 2010: Wolf Prize 2005: CNRS Gold Medal 1999: Gay-Lussac–Humboldt Prize 1999: Max Born Award 1991: Fernand Holweck Medal and Prize 1987: International Commission for Optics Award 1985: Commonwealth Award for Science and Invention 1983: Prix Servant
Acknowledgement Member of the Academia Europaea Member of the French Academy of Sciences Member of the French Academy of Technologies Foreign Member of the Royal Society Foreign Associate of the National Academy of Sciences Associate Member of the Royal Academy of Science, Letters and Fine Arts of Belgium Corresponding member abroad of the Austrian Academy of Sciences Fellow and Honorary Member of Optica Member of scientific advisory committee for EssilorLuxottica
Honorary degrees 2006: Université de Montréal 2008: Australian National University 2008: Heriot-Watt University 2010: University of Glasgow 2011: University of Haifa 2014: University of Waterloo 2018: City University of Hong Kong 2023: Université de Sherbrooke 2024: University of Minho 2025: National Taiwan University
Publications
Introduction aux lasers et à l'optique quantique (with G. Grynberg & C. Fabre), Paris, ed. Ellipses, 1997 Bose-Einstein Condensates and Atom Lasers (collectif book), London, ed. Plenum, 2000 Lévy Statistics and Laser Cooling: How Rare Events Bring Atoms to Rest (with F. Bardou, J.-Ph. Bouchaud & C. Cohen-Tannoudji), Cambridge, ed. Cambridge University Press, 2002 Einstein aujourd'hui (with M. Le Bellac, M. Leduc, F. Bouchet & É. Brunet), Paris, ed. CNRS, 2005 Introduction to Quantum Optics: From the Semi-classical Approach to Quantized Light (with G. Grynberg & C. Fabre), Cambridge, ed. Cambridge University Press, 2010 Single-Photon Generation and Detection: Physics and Application (collectif book), London, ed. Academic Press, 2013 Einstein et les révolutions quantiques, Paris, ed. CNRS, 2019 Einstein and the Quantum Revolutions, University of Chicago Press, 2024. Si Einstein avait su, Paris, ed. Odile Jacob, 2025
References
Publications
External links
Aspect's homepage Biography at CNRS Alain Aspect International Balzan Prize Foundation Why quantum theory is just like magic (and Einstein deserves more credit in this field than he gets), interview at Nature, 28 October 2024 Videos of Alain Aspect in the AV-Portal of the German National Library of Science and Technology