Fidelity and concurrence of conjugated states
Abstract
We prove some properties of fidelity (transition probability) and concurrence, the latter defined by a straightforward extension of Wootters' notation. Choose a conjugation and consider the dependence of fidelity or of concurrence on conjugated pairs of density operator. These functions turn out to be concave or convex roofs. Optimal decompositions are constructed. Some applications to two and tripartite systems illustrate the general theorems.
 Publication:

Physical Review A
 Pub Date:
 September 2000
 DOI:
 10.1103/PhysRevA.62.032307
 arXiv:
 arXiv:quantph/9909060
 Bibcode:
 2000PhRvA..62c2307U
 Keywords:

 03.67.a;
 03.65.Bz;
 89.70.+c;
 Quantum information;
 Information theory and communication theory;
 Quantum Physics;
 Mathematical Physics
 EPrint:
 10 pages, RevTex, Correction: Enlarged, reorganized version. More explanations