Phase structure and optical properties of the de Sitter Spacetime with KR field based on the Lyapunov exponentYun-Zhi Du, Huai-Fan Li, Yu-Bo Ma and Qiang GuEur. Phys. J. C, 85 1 (2025) 78DOI: https://doi.org/10.1140/epjc/s10052-025-13809-7