On characterizations of bistochastic Kadison-Schwarz operators on $M_2(\mathbb{C})$

Abstract

In this paper we describe bistochastic Kadison-Schawrz operators acting on $M_2(\mathbb{C})$. Such a description allows us to find positive, but not Kadison-Schwarz operators. Moreover, by means of that characterization we construct Kadison-Schawrz operators, which are not completely positive.

16 pages, 2 figures. arXiv admin note: text overlap with arXiv:1005.5532

References in corpus (2)

• A class of symmetric Bell diagonal entanglement witnesses - a geometric perspective
• Quantum-correlation breaking channels, quantum conditional probability and Perron-Frobenius theory