some of you might be interested in this new paper by Frank Verstraete. Computational complexity of interacting electrons and fundamental limitations of density functional theory http://www.nature.com/nphys/journal/vaop/ncurrent/abs/nphys1370.html <http://www.nature.com/nphys/journal/vaop/ncurrent/abs/nphys1370.html> -- Alejandro Perdomo Ph.D. Candidate in Chemical Physics. Harvard University 12 Oxford St #482, Cambridge, MA, 02138. perdomo(a)fas.harvard.edu -- Alejandro Perdomo Ph.D. Candidate in Chemical Physics. Harvard University 12 Oxford St #482, Cambridge, MA, 02138. perdomo(a)fas.harvard.edu