Non-perturbative Double Copy in Flatland

TL;DR

This paper develops a non-perturbative, Lagrangian framework for the double copy in two-dimensional scalar theories, revealing its field-theoretic structure and extending it to classical solutions and integrable models.

Contribution

It introduces a non-perturbative Lagrangian formulation of the double copy in 2D, including higher-dimension operators and classical solutions, broadening the theoretical understanding.

Findings

Derived a non-perturbative double copy at the Lagrangian level.

Established an all-order amplitudes double copy in perturbation theory.

Applied the double copy to integrable models, linking Lax connections and conserved currents.

Abstract

We derive a non-perturbative, Lagrangian-level formulation of the double copy in two spacetime dimensions. Our results elucidate the field theoretic underpinnings of the double copy in a broad class of scalar theories which can include masses and higher-dimension operators. An immediate corollary is the amplitudes-level double copy at all orders in perturbation theory. Applied to certain integrable models, the double copy defines an isomorphism between Lax connections, Wilson lines, and infinite towers of conserved currents. We also implement the double copy at the level of non-perturbative classical solutions, both analytically and numerically, and present a generalization of the double copy map that includes a fixed tower of higher-dimension corrections given by the Moyal algebra.