Spontaneous spin textures in dipolar spinor condensates: A Dirac string gas approach

We study the spontaneous spin textures induced by magnetic dipole-dipole interaction in ferromagnetic spinor condensates under various trap geometries. At the mean-field level, we show the system is dual to a Dirac string gas with a negative string tension in which the ground state spin texture can be easily determined. We find that three-dimensional condensates prefer a meronlike vortex texture, quasi-one-dimensional condensates prefer the axially polarized flare texture, while condensates in quasi-two-dimensions exhibit either a meron texture or an in-plane polarized texture.