What hath Weinberg wrought? Reflections on what Weinberg's papers on 'Nuclear Forces from Chiral Lagrangians' did and did not accomplish

TL;DR

This paper reflects on Weinberg's influential work applying chiral Lagrangians to nuclear physics, highlighting its impacts, debates, and the shift in expectations for nuclear calculations.

Contribution

It critically examines Weinberg's methods and their legacy, including the development of pionless EFT and epistemological changes in nuclear physics.

Findings

Chiral expansion organizes pion and photon interactions with nuclei.

Debates on inserting chiral-derived potentials into Schrödinger equations.

Pionless EFT reveals universal correlations in few-body systems.

Abstract

I discuss selected legacies of Weinberg's application of chiral Lagrangians to nuclear physics: (1) the use of the chiral expansion to organize the interaction of pions and photons with a nucleus; (2) the much-debated question of why and how the potential derived from a chiral Lagrangian should be inserted in the Schrodinger equation; (3) the emergence of "pionless EFT" as a tool for diagnosing universal correlations that are present in quantum few-body systems of very different sizes, and, perhaps most important of all, (4) an epistemological shift in what is expected of a nuclear-physics calculation.