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

Understand

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.