Andreev conductance of a one-dimensional interacting electron gas coupled with a superconductor

Andreev reflection in a one-dimensional interacting electron gas coupled with a bulk superconductor is studied theoretically. In the case of weak interaction we calculate the renormalized Andreev-reflection amplitude using a poor man's renormalization group approach, taking account of both the forward and backward scatterings due to the electron-electron interaction. The conductance as a function of temperature is obtained for arbitrary strength of the barrier potential at the normal-superconductor interface. We show that the resulting temperature dependence is stronger than that of single-barrier conductance in the one-dimensional interacting electron gas. It is also shown that any logarithmic temperature dependence does not appear in the Andreev conductance despite the presence of the backward scattering.