On kinetic theories with color and spin from amplitudes

TL;DR

This paper develops a framework connecting thermal currents and classical amplitude limits in theories with color and spin, extending to bi-adjoint scalars and higher-spin scalar QED, and derives related kinetic equations.

Contribution

It introduces a novel approach linking amplitude methods to kinetic equations for theories with color and spin, including bi-adjoint scalars and higher-spin fields.

Findings

Derived Vlasov-type kinetic equations for bi-adjoint scalars.

Established consistency between kinetic solutions and amplitude-based approaches.

Extended classical kinetic descriptions to theories with spin and color.

Abstract

We extend a previously developed approach to relate thermal currents in the high temperature regime and classical limits of amplitudes. We consider the bi-adjoint scalar theory, which has the basic structure of a cubic theory and which is related to QCD and gravity through the double copy. In addition, we consider a generalization of scalar QED to model classical spin, where massive scalars are complex higher-spin fields. We derive Vlasov-type kinetic equations for bi-adjoint scalars and study their iterative solutions, while for QED we use well-known kinetic equations. In both cases we find consistency between these solutions and the amplitude-like approach.