Vortex-antivortex pair creation in black hole thermodynamics

An isolated critical point is a peculiar thermodynamic critical point that occurs in the phase diagram of hyperbolic black holes in Kth-order Lovelock gravity in higher dimensions (with K odd) for special tuned Lovelock coupling constants. It corresponds to a ``merger'' of two swallowtails and is characterized by nonstandard critical exponents. Upon employing a recent proposal for assigning a topological charge to thermodynamic critical points, we argue that the isolated critical point offers an interpretation corresponding to the onset of a topological phase transition of a vortex-antivortex pair.