D-brane solitons and boojums in field theory and Bose-Einstein condensates

TL;DR

This paper demonstrates that D-brane solitons, originally studied in field theory, can be realized in two-component Bose-Einstein condensates, highlighting their similarities and differences with topological solitons in gauge theories.

Contribution

It introduces the concept of D-brane solitons in Bose-Einstein condensates and defines the boojum charge to characterize these composite topological structures.

Findings

D-brane solitons can be realized in Bose-Einstein condensates

The boojum charge characterizes the D-brane soliton in condensates

Comparison between solitons in gauge theory and condensates

Abstract

In certain field theoretical models, composite solitons consisting of a domain wall and vortex lines attached to the wall have been referred to as D-brane solitons. We show that similar composite solitons can be realized in phase-separated two-component Bose-Einstein condensates. We discuss the similarities and differences between topological solitons in the Abelian-Higgs model and those in two-component Bose-Einstein condensates. Based on the formulation of gauge theory, we introduce the "boojum charge" to characterize the "D-brane soliton" in Bose-Einstein condensates.