Yu Deng

Yu Deng (, born June 1989) is a Chinese mathematician and a professor of mathematics at the University of Chicago. He is known for his contributions to partial differential equations, fluid dynamics, and probabilistic analysis. He was awarded the Fields Medal in 2026 for his derivation of the Boltzmann equation, his derivation of wave kinetic equations from nonlinear dispersive systems, and his development of probabilistic approaches to non-linear dynamics.

Early life and education Deng was born in June 1989 in Kaifeng, Henan, China. His father was a software engineer, and his mother was a gastroenterologist.

As a child, Deng excelled in tournaments of the Chinese strategy board game Go. He then represented China in the 2006 International Mathematical Olympiad, where he won a gold medal at age 16.

Granted exemption from the Gaokao, Deng was admitted to Peking University in 2007, the same year as Hong Wang. He was an undergraduate there for two years until June 2009, when he transferred to the Massachusetts Institute of Technology (MIT), where he graduated with a Bachelor of Science in mathematics in 2011. His doctoral dissertation, completed under Alexandru D. Ionescu, was titled, "Long time behavior of some nonlinear dispersive equations". Ionescu recalled Deng as "brilliant from the beginning...even as a graduate student, without experience...he was very good at getting at the essence of the thing, picking up what matters in a problem."

Deng and his collaborators adapted these methods to systems of hard spheres. They derived the Boltzmann equation from Newtonian particle dynamics over long time scales, overcoming the repeated-collision problem that had restricted earlier results to very short times. For a periodic-box model, their work combined with earlier Boltzmann-to-Navier–Stokes limits to establish a rigorous passage from microscopic particle motion to macroscopic fluid behaviour in a major case of Hilbert's sixth problem.

Awards In 2021, Deng received a Sloan Research Fellowship in recognition of outstanding early-career research. In 2026, he was awarded the Clay Research Award for "remarkable derivation of the Boltzmann equation for long times, starting from a system of hard spheres".

On 23 July 2026, Deng was awarded the Fields Medal alongside Hong Wang, John Pardon, and Jacob Tsimerman at the International Congress of Mathematicians in Philadelphia, Pennsylvania. He and Hong Wang are the first Chinese citizens to be awarded the Fields Medal.