Absolute fully entangled fraction from spectrum Tapaswini Patro, Kaushiki Mukherjee, Mohd Asad Siddiqui, Indranil Chakrabarty and Nirman Ganguly Eur. Phys. J. D, 76 7 (2022) 127 Published online: 20 July 2022 DOI: 10.1140/epjd/s10053-022-00458-8