Large-Scale Structure of the Universe: SGCU Theory Version 2.6 — From Topological Defects of the Ψ Field to Dark Matter Halos, Galaxy Rotation Curves, and the Cosmic Web

In standard cosmology, dark matter is treated as an unknown particle, and its distribution is described by numerical simulations (e.g., the ΛCDM model). Based on the SGCU framework, this paper proposes that dark matter is not a particle, but topological defects (kinks, vortices) of the Ψ field. The large-scale structure of the universe — dark matter halos, galaxy rotation curves, and the cosmic web — is the direct manifestation of the gravitational clustering and topological arrangement of these defects. Core claims: · Dark matter halos: static defect solutions of Ψ naturally produce a cored density profile (rather than a cusp), requiring no additional tuning. This explains the persistent core-cusp problem. · Galaxy rotation curves: the defect density distribution determines the gravitational potential, predicting that rotation curves become flat at large radii, and may exhibit weak oscillations in the outer regions — a feature not predicted by continuous dark matter models. · Cosmic web: vortex lines of Ψ tend to arrange into a three-dimensional network, directly mapping to the filamentary dark matter skeleton of the cosmic web. Ordinary matter settles onto these skeletons via gravity, forming visible galaxies. This paper completes the full scale loop of SGCU from the microscopic to the extreme to the macroscopic: dark matter is no longer an invisible particle, but a defect configuration of space itself.