Causality Constraints on Modifications of Einstein Gravity

Abstract

Causality and unitarity as old principles, together with modern techniques, can put strong constraints on EFT. We think of modifications of Einstein gravity as low-energy gravity EFT, we will demonstrate how causality and unitarity can constrain the modifications by using dispersive sum rules of 2->2 amplitudes. Our bounds imply that gravitational interactions must shut off uniformly in the G->0 limit, and prove the scaling with higher-spin mass. Possible experimental implications in D=4 is discussed. In D=5, we also first provide numerical bound on central charges in holographic CFTs.

About the Speaker

Mr. LI Yue-Zhou is a final-year PhD student at McGill University. He has a broad range of interests and is actively working on aspects of S-matrix and effective field theories, conformal field theory, AdS/CFT correspondence etc. He is particularly interested in applying the bootstrap methods to different physics problems.

About the Program

For more information, please refer to the program website at http://iasprogram.ust.hk/particle_theory.