Exploring weight-dependent density-functional approximations for ensembles in the Hubbard dimer Killian Deur, Laurent Mazouin, Bruno Senjean and Emmanuel Fromager Eur. Phys. J. B, 91 7 (2018) 162 Published online: 16 July 2018 DOI: 10.1140/epjb/e2018-90124-7