Robust stationary distributed discord in Jordan-Wigner fermion system   under perturbations of initial state
  We investigate the Jordan-Wigner fermion clusters with the stationary distributed pairwise quantum discord. Such clusters appear after the Jordan-Wigner transformation of a spin chain governed by the nearest-neighbor XY-Hamiltonian with the particular initial state having one polarized node. We show that the quantum discord stationarity in such systems is not destroyed by the "parasitic" polarization of at least two types. First type appears because the initial state with a single polarized node is hardly realizable experimentally, so that the low polarization of neighboring nodes must be taken into account. Second, the additional noise-polarization of all nodes is unavoidable. Although the stationarity may not be destroyed by perturbations of the above two types, the parasitic polarizations deform the distribution of the pairwise discord and may destroy the clusters of correlated fermions with equal pairwise discords. Such deformations are studied in this paper. 
E.B. Fel'dman and A.I. Zenchuk
quant-ph