It even turns out that in a mathema

It even turns out that in a mathematically strict analysis, von Neumann entanglement does not allow a general prediction of resource usage: this is because one can construct artificial eigenvalue spectra that allow or forbid efficient simulation, while their von Neumann entanglement would suggestthe opposite, following the above argument [95]. Typical many-body states of interest, however, donot have such ‘‘pathological’’ spectra. In fact, Renyi entanglement entropies, a generalization of vonNeumann entanglement entropies, do allow mathematically rigourous connections [95], but usuallyare hard to calculate, with criticality in one dimension as an exception due to conformal field theory.