Claude Cohen-Tannoudji

In 1958 Claude Cohen-Tannoudji married Jacqueline Veyrat, a high school teacher. The couple had three children. Unfortunately, one of their sons, Alain, died in 1993 after suffering from a long illness, at the age of 34.

Claude Cohen-Tannoudji was born on 1 April 1933 in Constantine, Algeria, to Algerian Jewish parents Abraham Cohen-Tannoudji and Sarah Sebbah. Algeria was then part of France.

Even though he grew up during a politically chaotic period in Europe and French colonies, his family was able to escape persecution at the hands of Nazis due the arrival of the Americans in Algeria. He completed his primary and secondary school education in Algiers during the relatively peaceful years before the Algerian War of Independence and left Algiers for Paris in 1953.

In Paris, he joined the École Normale Supérieure (ENS) where he spent four highly interesting years. He attended lectures in mathematics given by Henri Cartan and Laurent Schwartz, and in physics by Alfred Kastler. Initially he was more interested in mathematics but soon he shifted his focus to physics, partly because of his great admiration for Kastler.

He joined Kastler’s small group of researchers in 1955 for his diploma work. The same year he spent two months at Les Houches summer school in the Alps where he attended lectures by the likes of J. Schwinger, N. Ramsey, G. Uhlenbeck, W. Pauli, A. Abragam, A. Messiah, and C. Bloch.

In the midst of the Algerian War, he was conscripted into the army interrupting his studies. He served in the army for 28 months, a part of which he spent in a scientific department supervised by Jacques Emile Blamont where he studied the upper atmosphere with rockets releasing sodium clouds at the sunset.

After completing his doctorate, Cohen-Tannoudji accepted a teaching position at the University of Paris at the urging of his mentor Kastler. Thus he began teaching quantum mechanics while continuing to work as a research scientist in the department of physics at ENS. Over the ensuing period his research team developed the model of the dressed atom.

His teaching experiences during this time led to the publication of the popular textbook ‘Mécanique quantique’ (Quantum Mechanics), which he wrote with two of his colleagues.

In 1973, he moved to the Collège de France as a professor. The job was a very enriching one which also resulted in the publication of two books on quantum electrodynamics and quantum optics written with Jacques Dupont-Roc and Gilbert Grynberg.

He lectured on the emerging field of radiative forces in the early 1980s. In the mid-1980s he began the work which would ultimately fetch him to the Nobel Prize. He formed a new experimental group with Alain Aspect, Christophe Salomon, and Jean Dalibard in 1984 and worked on techniques of laser cooling and trapping.

By the late 1980s physicists Steven Chu and William Daniel Phillips had also performed some significant research in laser cooling. Cohen-Tannoudji and his colleagues furthered the work done by Chu and Phillips to come up with newer discoveries that paved the way for the development of several new practical applications.

Cohen-Tannoudji collaborated with his colleagues at ENS to expand on the work on laser cooling done by physicists Steven Chu and William Daniel Phillips to explain a seeming discrepancy in theory. He took a statistical approach to laser cooling with the use of stable distributions and devised new mechanisms for cooling and trapping atoms with laser light.