Incoherent tunnelling through two quantum dots with Coulomb interaction
  The Ohmic conductance and current through two quantum dots in series is investigated for the case of incoherent tunnelling. A generalised master equation is employed to include the discrete nature of the energy levels. Regions of negative differential conductance can occur in the I-V characteristics. Transport is dominated by matching energy levels, even when they do not occur at the charge degeneracy points. 
P. Pals and A.MacKinnon (The Blackett Laboratory, Imperial College,   London, United Kingdom)