Electron pair current through the correlated quantum dot

We study the charge current transmitted through the correlated quantum dot characterized by a finite magnitude of the Coulomb interaction |U|. At low temperatures the correlations can lead to appearance of the spin (for U>0) or charge (for U<0) Kondo states qualitatively affecting the transport properties. We explore an influence of the charge Kondo effect on the electron pair tunneling introducing the auxiliary two-component model which describes the fluctuations between empty and doubly occupied states of the quantum dot.