Uhlmann's theorem for relative entropies

Giulia Mazzola, David Sutter, Renato Renner

Uhlmann's theorem states that, for any two quantum states $\ddot{I}{}_{AB}$ and $\ddot{I}{ƒ}_A$, there exists an extension $\ddot{I}{ƒ}_{AB}$ of $\ddot{I}{ƒ}_A$ such that the fidelity between $\ddot{I}{}_{AB}$ and $\ddot{I}{ƒ}_{AB}$…