Non-BPS Dirac-Born-Infeld Solitons

TL;DR

This paper demonstrates that CPn sigma model solitons, including non-BPS solutions, also solve Dirac-Born-Infeld equations, and compares their moduli space dynamics, revealing similarities and differences across models.

Contribution

It proves that CPn sigma model solitons satisfy DBI equations and analyzes the moduli space metrics for BPS and non-BPS solutions, highlighting differences for n>1.

Findings

CP1 sigma model solitons have identical moduli space metrics in both models

Non-BPS solitons of the sigma model also solve DBI equations

For n>1, the moduli space metrics differ between sigma model and DBI

Abstract

We show that CPn sigma model solitons solve the field equations of a Dirac-Born-Infeld (DBI) action and, furthermore, we prove that the non-BPS soliton/anti-soliton solutions of the sigma model also solve the DBI equations. Using the moduli space approximation we compare the dynamics of the BPS sigma model solitons with that of the associated DBI solitons. We find that for the CP1 case the metric on the moduli space of sigma model solitons is identical to that of the moduli space of DBI solitons, but for CPn with n>1 we show that the two metrics are not equal. We also consider the possibility of similar non-BPS solitons in other DBI theories.