Laser-cooling pioneer and Nobel laureate Claude Cohen-Tannoudji dies at 93

Claude Cohen-Tannoudji, the French physicist and Nobel laureate who died in Paris on October 22 at the age of 93, shared the 1997 Nobel Prize in Physics with Steven Chu and William Phillips. The trio were honored for their development of methods to cool and trap atoms using laser light. Chu and Phillips were recognized for their experimental work in the 1980s, which demonstrated that photon collisions could be employed to cool atomic gases to temperatures well below 1 mK.

Cohen-Tannoudji, however, delved deeper into the mystery of cooling atoms to temperatures far below the expectations of Doppler cooling. Theoretical work by Cohen-Tannoudji led to a breakthrough in cooling atoms to much colder temperatures. Collaborating with future Nobel laureate Alain Aspect and others, he successfully cooled a helium gas to 180 nK in 1995.

Born in Constantine, Algeria on April 1, 1933, Cohen-Tannoudji moved to France in 1953 before the start of the Algerian War of Independence. He pursued his education at the Ecole Normale Supérieure (ENS) in Paris, graduating in 1957 and subsequently completing his PhD under the guidance of Nobel laureates Alfred Kastler and Jean Brossel.

Cohen-Tannoudji's research focused on the theoretical and experimental aspects of optical pumping. He later taught physics at the University of Paris and mentored numerous PhD students, including Serge Haroche, who was awarded the 2012 Nobel Prize in Physics for his work on the measurement and manipulation of quantum systems. In addition to his pioneering research, Cohen-Tannoudji is renowned for his three-volume textbook Mécanique quantique, co-authored with Bernard Diu and Franck Laloë.

Translated into English as Quantum Mechanics, the book is celebrated for its innovative approach to teaching quantum physics.