Influence of pair coherence on charge tunneling through a quantum dot connected to a superconducting lead

We analyze the charge transport through a single level quantum dot coupled to a normal and superconducting lead where the electron pairs exist either as the coherent (for temperatures below T-c) or incoherent objects (in a region T-c < T < T-*). Practically, this situation can be encountered using the high T-c superconducting materials where precursor effects have been observed upon approaching T-c from above. Without restricting to any particular microscopic mechanism, we investigate the qualitative properties of nonequilibrium charge current caused by the electron pair coherence.