Cécile DeWitt-Morette

Cécile DeWitt-Morette passed away on 8 May 2017 in Austin, Texas. She is perhaps best known for establishing the Les Houches School of Physics, located in the French Alps, and for having thus contributed greatly to the development of physics during the second half of the 20th century. Over the years the school attracted prominent teachers, and many students later became prominent scientists in their own right. Recent Nobel laureate Kip Thorne attended Les Houches first as a student and then as a lecturer; he is one of 50 participants who have earned a Nobel Prize or Fields Medal.

Born in Paris on 21 December 1922, Cécile grew up in Caen, and she obtained her bachelor’s degree in science from the university there. On 6 June 1944, the day of the Normandy landing, while Cécile was taking her master’s exam at the University of Paris, bombs destroyed her home in Caen and killed most of her family.

Soon after, Cécile was hired by Frédéric Joliot-Curie to assist with tasks requiring theoretical knowledge. However, France lagged significantly in theoretical physics: No structured course on quantum mechanics had yet been offered. A conversation she had with Paul Dirac while visiting the UK led Cécile to realize her ignorance. Like other graduate students, she was expected to be trained abroad, and thus she prepared her doctoral thesis in Dublin under the direction of Walter Heitler. After she defended her thesis on the production of mesons, she left Paris for Copenhagen; in 1948 she went to the Institute for Advanced Study in Princeton, New Jersey. There she met a young physicist, Bryce DeWitt, who was as tall as she was short.

In the spring of 1951, Cécile married Bryce, which meant she would live outside of France, and she imposed on herself a condition to contribute to the redevelopment of physics in her motherland. Having experienced firsthand the deficiency of modern-physics instruction in France, she set out to remedy that. Through her energy, courage, and vision, she invented the concept of an autonomous international summer school with specific features: gathering a small group of carefully selected, promising students and eminent professors engaged in cutting-edge research; letting them work, live, and eat together for two-month sessions in a secluded and beautiful location; delivering extensive courses that progress from basic physics to recent advances; and publishing the lecture notes.

By the summer of 1951, Cécile was already able to launch the first session. Using her unique power of persuasion—Pierre-Gilles de Gennes said that no one could resist her “blue-eyed stare”—she garnered support for the project from influential physicists such as Louis Néel and Yves Rocard, obtained funds from the French government, found assistants, recruited outstanding lecturers, and advertised the school. Through a Girl Guide friend whose father had bought them in the 1920s, she borrowed several ancient alpine chalets overlooking the village of Les Houches and facing the Mont Blanc chain. She installed rudimentary housing and a classroom in a hayloft.

For two summer months that year, about 30 students—half French, half foreign—who paid only for their meals, were introduced to modern physics by an impressive list of teachers, including Léon van Hove, Walter Kohn, Wolfgang Pauli, Emilio Segrè, and Victor Weisskopf (shown in the photo with Cécile at Les Houches). Some students slept on straw, but the lack of comfort and the intensive work were balanced by a congenial atmosphere and mountain hiking or climbing during free time. Lasting relationships were created.

From 1951 to 1972, Cécile directed and developed her school with tireless energy; she spent every summer at Les Houches with her four daughters and often with Bryce. She transformed the school into an official institution, installed a scientific and administrative board, and obtained funding from various sources, including the NATO Science Committee after 1958. Over time, she organized the purchase of the school property, the remodel of old farms, and the construction of modern chalets for housing and a building with a classroom, a library, and working spaces.

As graduate-level instruction in Europe improved, the yearly sessions increasingly focused on specific themes and were organized by a scientific director, but Cécile resisted overspecialization. In 1958 she entrusted Philippe Nozières with an eight-week session on the many-body problem, at which I had the marvelous experience of discovering living physics. Other institutes created throughout the world since 1953 have used Les Houches as a model.

In parallel with the development of the Les Houches School, Cécile pursued her physics career in the US and eventually became the Jane and Roland Blumberg Centennial Professor at the University of Texas at Austin. She produced foundational work on path integrals, their classical limit, and their interplay with topology. She published articles on wave propagation and on general relativity, measured the deviation of the light of stars by the Sun during the 1972 eclipse, and directed the work of many students. She edited numerous volumes of the Les Houches proceedings, and with Yvonne Choquet-Bruhat she wrote an excellent two-volume book, Analysis, Manifolds and Physics.

Cécile offered me the great honor and pleasure of succeeding her in 1973 as director of the Les Houches School, which she had always regarded as her “child.” After retiring, she remained an active member of its board. Her successors, while following the advances of science, have preserved the spirit she instilled. Her school will remain her living legacy.