Clifford Cheung

Clifford W. Cheung is a Professor of Theoretical Physics in the Division of Physics, Mathematics and Astronomy at the California Institute of Technology (Caltech). A specialist in Physics, particularly at the interface of particle theory and quantum gravity, Cheung earned his B.S. from Yale University in 2004, M.A. from Harvard University in 2006, and Ph.D. from Harvard University in 2009. Following his graduate studies, he was a postdoctoral researcher at the University of California, Berkeley from 2009 to 2012. He joined Caltech in 2012 as an Assistant Professor of Theoretical Physics, was promoted to Professor in 2019, and since 2025 has served as the Founding Director of the Leinweber Forum for Theoretical Physics. In this role, he leads initiatives to support faculty, students, and postdocs in theoretical physics and foster collaborations with institutions such as UC Berkeley, the University of Chicago, Stanford, MIT, the Institute for Advanced Study, and the University of Michigan.

Cheung is a member of the Caltech Particle Theory Group and the Walter Burke Institute for Theoretical Physics. His research encompasses areas from supercolliders to the big bang and gravitational-wave physics, with contributions to scattering amplitudes and effective field theories. In 2014, he received the Alfred P. Sloan Research Fellowship for his work in theoretical particle physics. Key publications include "The Effective Field Theory of Inflation" (2008, Journal of High Energy Physics), which provides a framework for studying inflationary cosmology; "TASI Lectures on Scattering Amplitudes" (2017); "Proof of the Weak Gravity Conjecture from Black Hole Entropy" (2018); "Effective Field Theory for Extreme Mass Ratio Binaries" (2024, Physical Review Letters); and "Multipositivity Bounds for Scattering Amplitudes" (2025, Physical Review D). Cheung has presented lectures including TASI lectures on amplitudes and colloquia on topics such as unification from scattering amplitudes and from gluon scattering to black hole orbits, influencing advancements in fundamental physics.

Professional Email: clifford.cheung@caltech.edu