We investigate the extended Hubbard model as an approximation to the localand spatial entanglement of a one-dimensional chain of nanostructures where theparticles interact via a long range interaction represented by a `soft' Coulombpotential. In the process we design a protocol to calculate theparticle-particle spatial entanglement for the Hubbard model and show that, instriking contrast with the loss of spatial degrees of freedom, the predictionsare reasonably accurate. We also compare results for the local entanglementwith previous results found using a contact interaction (PRA, 81 (2010) 052321)and show that while the extended Hubbard model recovers a better agreement withthe entanglement of a long-range interacting system, there remain realisticparameter regions where it fails to predict the quantitative and qualitativebehaviour of the entanglement in the nanostructure system.
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