Paper detail

NMR dynamics of quantum discord for spin-carrying gas molecules in a closed nanopore

A local orthogonal transformation that transforms any centrosymmetric (CS) matrix of fourth order to the X form is found. A picewise-analytic-numerical formula Q=min{Q_π/2,Q_θ,Q_0}, where Q_π/2 and Q_0 are analytical expressions and the branch Q_θ is found by numerical searching the optimal measurement angle θ\in(0,π/2), is proposed to calculate the quantum discord Q of general X state. The developed approaches are applied to a quantitative description of recently predicted flickerings (periodic birth and death) of the quantum-information pair correlation between nuclear 1/2 spin of atoms or molecules of a gas (for examples Xe^129) in a finite asymmetric volume in the presence of a strong magnetic field.