The Yale Physics 44th Hanan Rosenthal Memorial Lecture, titled “Scale invariance, a hidden symmetry explored with quantum gases,” was given on April 28, 2025, by Jean Dalibard, Laboratoire Kastler Brossel, Collège de France.
Prof. Dalibard’s lecture was hosted by Nir Navon, associate professor of physics, who stated, “Prof. Dalibard is a towering figure in the AMO community. His career has been marked by numerous experimental and theoretical milestones of stunning breadth. In his youth, he participated in the Aspect experiment demonstrating the violation of Bell’s inequalities in 1982; as a graduate student, he provided, together with his advisor C. Cohen-Tannoudji, the theoretical explanation for the mechanism of laser cooling below the Doppler limit, coining the term ‘Sisyphus cooling’. He went on to lead groundbreaking experiments with quantum gases, such as the observation of quantized vortices in rotating Bose-Einstein condensates or the observation of the Berezinskii-Kosterlitz-Thouless topological phase transition, among many others. In addition to being a physicist of exceptional caliber, he gives talks of legendary clarity.”
In his Rosenthal Memorial Lecture, Prof. Dalibard showcased the remarkable degree of control that atomic physicists now have over ultracold atomic matter. With that control, he presented experimental explorations of fascinating hidden symmetries, such as scale invariance, which have provided new insights into the behavior of complex interacting quantum systems. He also presented a puzzling mystery: when ultracold atoms confined in sculpted laser traps are released from traps of certain shapes, they sometimes exhibit unexplained periodic recurrences despite their complex dynamics. These observations could point to novel mathematical properties of the nonlinear equations that describe these bosonic gases.
During his two-day stay at Yale, Prof. Dalibard met with several faculty members, graduate students, and postdocs from the Department. He also gave a YQI colloquium on the intriguing behavior of magnetic solitons.
Chiara Mingarelli, assistant professor of physics, commented, “Over dinner, our Rosenthal Lecturer, Jean Dalibard, mentioned his passion for rare books and his own personal collection. Following our conversation, I immediately reached out to our Beinecke librarians, Anna Franz and Kayleigh Bohemier, who generously arranged an impromptu viewing for us this afternoon.
Thanks to their extraordinary efforts, we were able to view two copies of Newton’s Principia—a first edition and a second edition personally sent to Yale by Newton himself. Anna and Kayleigh also made available rare volumes by Maxwell and Rutherford, which was particularly meaningful as Rutherford is Jean’s academic great-grandfather.
We are very grateful to Anna and Kayleigh for making this memorable visit possible on such short notice!!”
The Hanan Rosenthal Memorial Lecture was established in honor of physicist Hanan Rosenthal, a brilliant graduate student at Columbia University and instructor at Yale. This annual lecture in atomic physics, Rosenthal’s field, is given by a distinguished leader in the field. Initially, the lecture series alternated between Columbia and Yale, which were both significant in Hanan Rosenthal’s career; in recent years, the lecture has been held only at Yale University.