Near-BPS baby Skyrmions with Gaussian tails

摘要

A bstract We consider the baby Skyrme model in a physically motivated limit of reaching the restricted or BPS baby Skyrme model, which is a model that enjoys area-preserving diffeomorphism invariance. The perturbation consists of the kinetic Dirichlet term with a small coefficient ? as well as the standard pion mass term, with coefficient ? m 1 2 documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$ upepsilon {m}_1^2 $$end{document} . The pions remain lighter than the soliton for any ? and therefore the model is physically acceptable, even in the ? → 0 limit. The version of the BPS baby Skyrme model we use has BPS solutions with Gaussian tails. We perform full numerical computations in the ? → 0 limit and even reach the strict ? = 0 case, finding new nontrivial BPS solutions, for which we do not yet know the analytic form.