Elementary Andreev processes in a driven superconductor–normal metal contact

• Full counting statistics of a voltage-driven normal metal-superconductor contact.
• For a bias voltage below the superconducting gap the contact NS can be mapped onto an NN-contact with doubled voltage and counting fields.
• In the Andreev regime the transport characteristics can be obtained from the normal metal results.
• The elementary processes are single and electron- and hole-like Andreev transfers.
• Optimal quantization is obtained for half-integer Levitons.

We investigate the full counting statistics of a voltage-driven normal metal(N)–superconductor(S) contact. In the low-bias regime below the superconducting gap, the NS contact can be mapped onto a purely normal contact, albeit with doubled voltage and counting fields. Hence in this regime the transport characteristics can be obtained by the corresponding substitution of the normal metal results. The elementary processes are single Andreev transfers and electron- and hole-like Andreev transfers. Considering Lorentzian voltage pulses we find an optimal quantization for half-integer Levitons.