Claude Cohen-Tannoudji

Origins and early life

Claude Cohen-Tannoudji was born on 1 April 1933 in Constantine, then in French Algeria, into a Jewish family that had come from Tangier and settled in Tunisia and then in Algeria in the sixteenth century, after fleeing Spain during the Inquisition. His parents lived modestly and cared above all for their children's education, and his father, a self-taught reader of biblical and Talmudic texts, passed on to him what he regards as the fundamental features of the Jewish tradition: studying, learning and sharing knowledge.

The American landing in Algeria in November 1942 spared the family the Nazi persecution then spreading across Europe, and in 1953 he left Algiers for the École Normale Supérieure in Paris, where he attended Alfred Kastler's lectures.

Work and career

After twenty-eight months of military service in the Algerian war, he returned to the laboratory of Kastler and Jean Brossel, saw on Christmas Eve 1960 the light shifts his calculations had predicted, and completed his doctorate in December 1962. His teaching at the University of Paris gave rise to the textbook Quantum Mechanics, written with Bernard Diu and Franck Laloë. From 1973 to 2004 he held the chair of atomic and molecular physics at the Collège de France, where his group, with Alain Aspect, Jean Dalibard and Christophe Salomon, found new ways to cool and trap atoms with laser light, among them what they named Sisyphus cooling in 1986. This work opened the range of millionths and even billionths of a degree above absolute zero to laser cooling.

Recognition

In 1997 he shared the Nobel Prize in Physics with Steven Chu and William Phillips for development of methods to cool and trap atoms with laser light. He married Jacqueline, a high-school physics and chemistry teacher, in 1958, and they raised three children; they lost their eldest son, Alain, to a long illness in 1993, and he dedicated his Nobel lecture to Alain's memory.