Exposed positive maps in M_4(C)

TL;DR

This paper demonstrates that Breuer-Hall maps in 4x4 complex matrices have the strong spanning property, proving they are exposed in the convex cone of positive maps, which enhances understanding of their structural role.

Contribution

The paper proves that Breuer-Hall maps in M_4(C) are exposed positive maps by establishing their strong spanning property, a novel result in the study of positive maps.

Findings

Breuer-Hall maps in M_4(C) are exposed in the convex cone of positive maps.

They possess the strong spanning property.

This advances the structural understanding of positive maps in quantum information theory.

Abstract

It is shown that the family of so called Breuer-Hall maps in M_4(C) possesses strong spanning property and hence they are exposed in the convex cone of positive maps in M_4(C)