Origin of Soft Limits from Nonlinear Supersymmetry in Volkov-Akulov Theory

TL;DR

This paper investigates the origin of soft limits in nonlinear supersymmetry within the Volkov-Akulov theory, demonstrating how background field techniques reveal the algebraic structure underlying these limits.

Contribution

It applies a novel background field method to the Volkov-Akulov model, connecting soft limits to the algebra of nonlinear supersymmetries at tree level.

Findings

Background field expansion reproduces nonlinear supersymmetry transformations.

Double soft limit aligns with algebraic identities of nonlinear symmetries.

Method confirms the connection between soft limits and symmetry algebra.

Abstract

We apply the background field technique, recently developed for a general class of nonlinear symmetries, at tree level, to the Volkov-Akulov theory with spontaneously broken N=1 supersymmetry. We find that the background field expansion in terms of the free fields to the lowest order reproduces the nonlinear supersymmetry transformation rules. The double soft limit of the background field is, in agreement with the new general identities, defined by the algebra of the nonlinear symmetries.