Double Copy of Radiation-State Geometry

Determine whether the relation between gauge-theory and gravitational radiation extends to the geometry of their radiation states, including the coherent-state structures and associated phase-space data.

Background

The phase-space formalism associates inclusive radiation with coherent representatives whose dependence on hard scattering data defines a Berry connection and related quantum geometry. The paper suggests that this structure may offer a new setting in which to study classical gauge–gravity double-copy relations.

Whether the double copy extends from radiation fields and equations of motion to the geometry of radiation states is left as an explicit future question.

References

The phase-space formulation may also provide a useful way to study the double copy beyond perturbation theory. Since several recent approaches formulate aspects of the classical double copy directly at the level of fields and equations of motion [168–176], it is natural to ask whether the relation between gauge and gravitational radiation also extends to the geometry of their radiation states. In principle, the work of Ilderton and Lindved on the double copy of coherent-state gauge backgrounds into curved gravitational backgrounds could be useful here [42]. We look forward to exploring these questions in future work.

— Inclusive Radiation and Backreaction from the Phase-Space S-Matrix  (2608.21318 - Moynihan, 21 Aug 2026) in Section 11, Discussion, p. 68