Mixed-state sensitivity of several quantum-information benchmarks

摘要

We investigate an imbalance between the sensitivity of the common state measures-fidelity, trace distance, concurrence, tangle, von Neumann entropy, and linear entropy-when acted on by a depolarizing channel. Further, in this context we explore two classes of two-qubit entangled mixed states. Specifically, we illustrate a sensitivity imbalance between three of these measures for depolarized (i.e., Werner-state-like) nonmaximally entangled and maximally entangled mixed states, noting that the size of the imbalance depends on the state's tangle and linear entropy.