We discuss the general transport properties of superconducting quantum pointcontacts. We show how these properties can be obtained from a microscopic modelusing nonequilibrium Green function techniques. For the case of a one-channelcontact we analyze the response under different biasing conditions: constantapplied voltage, current bias and microwave-induced transport. Currentfluctuations are also analyzed with particular emphasis on thermal andshot-noise. Finally, the case of superconducting transport through a resonantlevel is discussed. The calculated properties show a remarkable agreement withthe available experimental data from atomic-size contacts measurements. Wesuggest the possibility of extending this comparison to several otherpredictions of the theory.
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