In this paper, we consider the minimal entropy of two-qubit states transmitted through two uses of a noisy quantum channel, which is modeled by the action of a completely positive trace-preserving (or stochastic) map. We provide strong support for the conjecture that this minimal entropy is additive, namely that the minimum entropy can be achieved when product states are transmitted. Explicitly...

A statistic based algorithm for watermarking 2D vector maps is proposed. Instead of 2D coordinates, a one-dimensional distance sequence extracted from the original map is used as the cover data to achieve the shape-preserving ability. The statistical feature of the cover data is utilized for data embedding. Experiment results indicate the scheme’s better performance in invisibility, as well as ...

For area-preserving Hénon-like maps and their compositions, we consider smooth perturbations that keep the reversibility of initial but destroy conservativity. For constructing such perturbations, use two methods, a new method based on reversible properties written in so-called cross-form, classical Quispel-Roberts variation involutions map. We study symmetry breaki...