Thermal quench dynamics of visons in gapless Kitaev spin liquid

We study the relaxation dynamics of visons ($\mathbb{Z}_2$ flux excitations) in the isotropic Kitaev honeycomb model following a thermal quench from an infinitely high temperature to the low-temperature regime. The post-quench dynamics is simulated by a diffusion-reaction process, governed by the thermal hopping of visons under their effective interactions. We identify three distinct dynamical regimes emerging from the interplay between the quantum nature of visons and thermal fluctuations, controlled by the post-quench temperature. At ultra-low temperatures, we observe the emergence of metastable $\sqrt{3}\times\sqrt{3}$ vison crystal domains. In the intermediate temperature regime, the melting of these vison crystals exhibits novel annihilation dynamics.