Stable subspaces of positive maps of matrix algebras

Abstract

We study stable subspaces of positive extremal maps of finite dimensional matrix algebras that preserve trace and matrix identity (so-called bistochastic maps). We have established the existence of the isometric-sweeping decomposition for such maps. As the main result of the paper, we have shown that all extremal bistochastic maps acting on the algebra of matrices of size 3x3 fall into one of the three possible categories, depending on the form of the stable subspace of the isometric-sweeping decomposition. Our example of an extremal atomic positive map seems to be the first one that handles the case of that subspace being non-trivial. Lastly, we compute the entanglement witness associated with the extremal map and specify a large family of entangled states detected by it.

11 pages. Added the computation of the entanglement witness associated with the provided example of an extremal map. Corrected typographical errors. Added acknowledgements

Cited by in corpus (6)

• Diagonal unitary and orthogonal symmetries in quantum theory
• Generating and detecting bound entanglement in two-qutrits using a family of indecomposable positive maps
• A class of bistochastic positive optimal maps in $M_d(\mathbb{C})$
• Merging of positive maps: a construction of various classes of positive maps on matrix algebras
• $k$-Positive Maps: New Characterizations and a Generation Method
• Non-Markovianity and entanglement detection