Classical light thermalization toward negative temperature equilibrium states in optical fibers and extension to the quantum regimeLucas Zanaglia, Kilian Baudin, Josselin Garnier, Adrien Fusaro, Claire Michel, Valérie Doya, Guy Millot and Antonio PicozziEPJ Web Conf., 335 (2025) 07006DOI: https://doi.org/10.1051/epjconf/202533507006