Conformal Geometry and Regularization of Disclinations by a Cosmological Constant in $(2+1)$ Dimensions

Abstract

We investigate the effect of a cosmological constant $\Lambda$ on the geometry generated by a two-dimensional disclination in a conformal metric framework. For $\Lambda>0$, we obtain an exact analytic solution of the Liouville-type equation, which regularizes the defect core, preserves the topological charge, and yields a compact space with finite volume and positive curvature. For $\Lambda<0$, the solution must be obtained numerically and asymptotically approaches $R \to 3\Lambda < 0$, producing an open hyperbolic geometry with divergent volume. In both regimes, the curvature profile is governed solely by the disclination strength $\alpha$, while the sign of $\Lambda$ dictates the global phase: compact and confined for $\Lambda>0$, hyperbolic and delocalized for $\Lambda<0$. This establishes a clear geometric dichotomy and shows that the cosmological constant provides a natural analytic regularization beyond cutoff-based treatments, with implications for analog gravity and two-dimensional condensed matter systems.