Finite energy Dirac-Born-Infeld monopoles and string junctions

TL;DR

This work shows that a single D3-brane in a supergravity D3-brane background supports finite-energy, non-singular abelian BIon monopoles and dyons that preserve ${\tfrac{1}{2}}$ or ${\tfrac{1}{4}}$ of ${\cal N}=4$ supersymmetry and saturate a Bogomol'nyi-type bound. The authors derive the D3-brane Hamiltonian in the warped background, establish a finite-energy bound, and construct explicit BIon solutions; in a two-centre background they obtain 1/4 SUSY string-junction dyons interpreted as three-string junctions. They extend these results to M-theory by showing the dual M5-brane picture yields finite-tension self-dual strings and intersecting self-dual strings, aligning with the D3-brane junctions under dualities. Overall, the paper provides a coherent abelian DBI realization of string junctions and their M-theory counterparts, connecting worldvolume solitons to brane backgrounds and SYM dualities. The findings illuminate how finite-energy, BPS-like solitons arise from brane in brane backgrounds and highlight the role of harmonic functions and background warping in regulating energies of otherwise singular configurations.

Abstract

It is shown that the worldvolume field theory of a single D3-brane in a supergravity D3-brane background admits finite energy, and non-singular, abelian monopoles and dyons preserving 1/2 or 1/4 of the ${\cal N}=4$ supersymmetry and saturating a Bogomol'nyi-type bound. The 1/4 supersymmetric solitons provide a worldvolume realisation of string-junction dyons. We also discuss the dual M-theory realisation of the 1/2 supersymmetric dyons as finite tension self-dual strings on the M5-brane, and of the 1/4 supersymmetric dyons as their intersections.

Figures (2)

• Figure 1: The string junction described in the text.
• Figure 2: The procedure described in the text to assign directions to the strings.