Relating the curvature of De Sitter universe to open quantum Lamb shift spectroscopy Hardik Bohra, Sayantan Choudhury, Prashali Chauhan, Purnima Narayan, Sudhakar Panda and Abinash Swain Eur. Phys. J. C, 81 2 (2021) 196 Published online: 27 February 2021 DOI: 10.1140/epjc/s10052-021-08977-1