Hayden Lee is an assistant professor in the Department of Physics and Astronomy and a member of the Center for Particle Cosmology at the University of Pennsylvania, where he has served since 2024. He earned his PhD from the Department of Applied Mathematics and Theoretical Physics at the University of Cambridge in 2017, following a BSc (Hons) from the University of Canterbury and an MASt from Cambridge. He previously held postdoctoral positions at the Center for the Fundamental Laws of Nature at Harvard University (2017–2021) and the Kavli Institute for Cosmological Physics at the University of Chicago (2021–2024). As a theoretical physicist, his research focuses on the physics of the early universe and scattering of elementary particles, applying techniques from high-energy physics such as scattering amplitudes, the cosmological bootstrap, conformal field theory, holography, and effective field theory to probe fundamental laws, locality, unitarity, symmetries, and cosmological correlators.