On the learnability of quantum state fidelityNorhan Elsayed Amer, Walid Gomaa, Keiji Kimura, Kazunori Ueda and Ahmed El-MahdyEPJ Quantum Technol., 9 1 (2022) 31DOI: https://doi.org/10.1140/epjqt/s40507-022-00149-8