The Saturation of Several Universal Inequalities in Information-Processing
Lin Zhang, Junde Wu, and Shao-Ming Fei
Contact the author: Please use for correspondence this email.
Submission date: 12. Aug. 2015
published in: Communications in theoretical physics, 63 (2015) 4, p. 427-430
DOI number (of the published article): 10.1088/0253-6102/63/4/427
Download full preprint: PDF (93 kB)
Strong subadditivity inequality of quantum entropy, proved by Lieb and Ruskai, is a powerful tool in quantum information theory. The fact that the strong subadditivity inequality saturated only by so-called Markov states is obtained in the recent literature [P. Hayden et al., Commun. Math. Phys. 246, 359 (2004).]. In this paper, we give a characterization of another equivalent version for strong subadditivity inequality. We discuss the coherent information saturating its upper bound as well. A necessary and sufficient condition for this saturation is derived. The possible applications are discussed.