Comment on "Entanglement transformation between two-qubit mixed states by LOCC" [Phys. Lett. A 373 (2009) 3610]
arXiv:1008.2941 · doi:10.1016/j.physleta.2010.09.029
Abstract
The paper [Phys. Lett. A 373 (2009) 3610] by D.-C. Li analyzes the transformation between two-qubit mixed states by local operations and classical communication. We show that the proof of the main theorem, Theorem 2.6 in [Phys. Lett. A 373 (2009) 3610] is not complete. Therefore the generalization of Nielsen's theorem to mixed states still remains an open problem.
improved version due to the valuable suggestions of the two anonymous referees