by Abhay Ashtekar
It is a pleasure and great honor to participate in this celebration of Mme Choquet’s 100th birthday. She has been an inspiring figure for me since I studied her early work on Einstein’s equations as a Ph.D. student of Bob Geroch’s almost 50 years ago. Already then she was a legend as an early pioneer exploring these equations using rigorous methods from geometric analysis. Indeed, papers she wrote already in the 1950s are such towering landmarks that they continue to be important, and cited even today! My admiration for her work grew over the subsequent years as I came to know more about her deep contributions, not only to general relativity but also to the global existence and uniqueness of solutions to gauge theories. I then had the privilege of being her colleague at the Jussieu campus in the eighties, as a Professeur at Paris VI.1 Our paths did not cross regularly. But her warm welcome in Paris, and scientific discussions at seminars and “Journées Relativistes”,2 were among the highlights of my academic life in France. The Paris academic scene was not easy for me to navigate and I am grateful to have had a guide in Mme Choquet during those years.
In the subsequent 20 years or so years my own research was focused more on quantum gravity and even my contributions to classical general relativity have been more at the interface of geometry and physics rather than geometry and analysis. Nonetheless, I always found Mme Choquet’s work inspiring. Her book, Analysis, Manifolds and Physics, has been on the most used book-shelf in my office since the late 70s! When she was awarded the Dannie Heineman Prize by the American Physical Society in 2003, I wrote to her expressing my sentiments on hearing the news: Most prizes honor the recipients, but on rare occasions it is the recipients who make the prize more prestigious. I feel that the Heineman prize became much more significant after 2003! In more recent years, I had the privilege of interacting with Mme Choquet in person at a KITP workshop in Santa Barbara, a Marcel Grossmann Meeting in Rome and at the celebration of the 100th anniversary of General Relativity in Berlin. On the Santa Barbara campus, we all watched with great admiration as she rode her bicycle in a cheerful, carefree manner. She had not changed over all those years — there was the same kindness radiating from her, the same mathematical rigor, and the same simplicity in her demeanor, providing us with a role model on how to live a productive and fulfilling life with inner serenity.
And then, over the last couple of years, I came to read of her life as a student in occupied France.3 In 1944, when Yvonne’s father, Georges Bruhat — a physicist and the Deputy Director of the Paris École Normale Supérieure — refused to cooperate with the Gestapo, they arrested Berthe Hubert Bruhat — Yvonne’s mother — and threatened to kill her the following day. And Yvonne pleaded with the Gestapo to allow her to take her mother’s place. When I read this, my heart melted and there were tears in my eyes. This was a whole new dimension of Mme Choquet that I knew nothing about. To have made such deep contributions to mathematics and to have attained the inner serenity in spite of enduring such traumatic events early on, made my already enormous admiration and respect grow a thousand fold. What a remarkable life you have led, Mme Choquet! I feel fortunate to have known you in person.
Abhay Ashtekar is the Evan Pugh Professor of Physics and holds the Eberly Chair at The Pennsylvania State University. He founded the Institute for Gravitation and the Cosmos in 1993 and served as its Director until 2021.
