

Preprint 38/2015
The Saturation of Several Universal Inequalities in Information-Processing
Lin Zhang, Junde Wu, and Shao-Ming Fei
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Submission date: 12. Aug. 2015
Pages: 12
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
Bibtex
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Abstract:
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.