Decomposability of extremal positive unital maps on M₂(ℂ)

• Autorzy: Władysław A. Majewski , Marcin Marciniak
• Języki publikacji: EN

Abstrakty

EN

A map φ: Mₘ(ℂ) → Mₙ(ℂ) is decomposable if it is of the form φ = φ₁ + φ₂ where φ₁ is a CP map while φ₂ is a co-CP map. It is known that if m = n = 2 then every positive map is decomposable. Given an extremal unital positive map φ: M₂(ℂ) → M₂(ℂ) we construct concrete maps (not necessarily unital) φ₁ and φ₂ which give a decomposition of φ. We also show that in most cases this decomposition is unique.

Kategorie tematyczne

• 47B65: Positive operators and order-bounded operators
• 47L07: Convex sets and cones of operators

• Wydawca: Institute of Mathematics Polish Academy of Sciences
• Czasopismo: Banach Center Publications
• Rocznik: 2006
• Tom: 73
• Numer: 1
• Strony: 347-356

Daty

wydano

2006

Twórcy

autor

Władysław A. Majewski

• Institute of Theoretical Physics and Astrophysics, Gdańsk University, Wita Stwosza 57, 80-952 Gdańsk, Poland

autor

Marcin Marciniak

• Institute of Theoretical Physics and Astrophysics, Gdańsk University, Wita Stwosza 57, 80-952 Gdańsk, Poland

Identyfikatory

DOI

10.4064/bc73-0-27