Quartets and the current-phase structure of a double quantum dot superconducting bijunction at equilibrium Denis Feinberg, Thibaut Jonckheere, Jérôme Rech, Thierry Martin, Benoît Douçot and Régis Mélin Eur. Phys. J. B, 88 4 (2015) 99 Published online: 13 April 2015 DOI: 10.1140/epjb/e2015-50849-3