Full counting statistics of interacting quantum dots contacted by a   normal metal and a superconductor
  We investigate the effects of Coulomb interaction on charge transfer through a quantum dot attached to a normal and a superconducting lead. While for voltages much larger than the gap we recover the usual result for normal conductors, for voltages much smaller than the gap superconducting correlations lead to a drastically different behavior. Especially, the usual charge doubling in the normal case is reflected in the occurence of quartets due to the onsite interaction. 
H. Soller and A. Komnik
cond-mat.mes-hall