Spectrum-generating Symmetries for BPS Solitons

TL;DR

The paper identifies a new class of duality symmetries that actively generate the spectrum of BPS solitons, involving a unique scaling transformation that connects solitons of different masses, with implications for quantum anomalies.

Contribution

It introduces a novel spectrum-generating symmetry involving a scaling transformation, independent of standard supergravity symmetries, for BPS solitons in any dimension.

Findings

Existence of nonlinearly realised duality symmetries for BPS solitons.

A single scaling transformation maps BPS solitons with different masses.

Fundamental BPS solitons may be resistant to quantum anomalies.

Abstract

We show that there exist nonlinearly realised duality symmetries that are independent of the standard supergravity global symmetries, and which provide active spectrum-generating symmetries for the fundamental BPS solitons. The additional ingredient, in any spacetime dimension, is a single scaling transformation that allows one to map between BPS solitons with different masses. Without the inclusion of this additional transformation, which is a symmetry of the classical equations of motion, but not the action, it is not possible to find a spectrum-generating symmetry. The necessity of including this scaling transformation highlights the vulnerability of duality multiplets to quantum anomalies. We argue that fundamental BPS solitons may be immune to this threat.