Skyrmion in two-component holographic superfluids

In the two-component Ginzburg-Landau theory of superfluidity or superconductivity, a pair of fractional vortices form a composite type of topological defect, usually referred to as a baby skyrmion, or a skyrmion for convenience. In this paper, we initiate the construction of such a skyrmion in the holographic model of two-component superfluids. As a result, two types of skyrmion configurations are found, where the monopole-type of one is constructed directly by solving the static equations of motion while the dipole-type of one is obtained by resorting to the time evolution method. In addition, we find that the existence of these two types of skyrmion depends on the inter-component coupling, reminiscent of the situation in the baby skyrmion model.
17 pages, 5 figures , minor improvements made, typos corrected, reference added