Unifying Relations for Scattering Amplitudes
Clifford Cheung, Chia-Hsien Shen, Congkao Wen
TL;DR
This work introduces a set of Lorentz-invariant differential operators that transmute tree-level scattering amplitudes into amplitudes of a broad web of theories, uncovering a unified structure linking YM, gravity, BI, DBI, SG, NLSM, and BS in arbitrary dimensions. By starting from extended gravity (gravity with a dilaton and two-form) and applying trace, insertion, and longitudinal operators, the authors generate the S-matrices of diverse theories and show that core structures like KLT, BCJ, and CHY naturally descend through transmutation. They provide a constructive, inductive proof that these relations hold at all multiplicities, analyze factorization and large-$z$ behavior, and establish a coherent infrared picture where soft theorems and Adler zeros are inherited across the web. The framework also accommodates UV completions and connects to string-theory amplitudes via open-string and Z-theory constructions, suggesting deep, practical ways to transport known results across theories. Overall, transmutation offers a powerful, dimension-agnostic lens on the unity of scattering amplitudes and their symmetries, with potential extensions to fermions and loops.
Abstract
We derive new amplitudes relations revealing a hidden unity among wide-ranging theories in arbitrary spacetime dimensions. Our results rely on a set of Lorentz invariant differential operators which transmute physical tree-level scattering amplitudes into new ones. By transmuting the amplitudes of gravity coupled to a dilaton and two-form, we generate all the amplitudes of Einstein-Yang-Mills theory, Dirac-Born-Infield theory, special Galileon, nonlinear sigma model, and biadjoint scalar theory. Transmutation also relates amplitudes in string theory and its variants. As a corollary, celebrated aspects of gluon and graviton scattering like color-kinematics duality, the KLT relations, and the CHY construction are inherited traits of the transmuted amplitudes. Transmutation recasts the Adler zero as a trivial consequence of the Weinberg soft theorem and implies new subleading soft theorems for certain scalar theories.
