Two-qubit mixed states and teleportation fidelity: purity, concurrence, and beyond Sumit Nandi, Chandan Datta, Arpan Das and Pankaj Agrawal Eur. Phys. J. D, 72 10 (2018) 182 Published online: 16 October 2018 DOI: 10.1140/epjd/e2018-90252-2