Andreev scattering in the asymmetric ladder with preformed bosonic pairs

We discuss the phase coherence that emanates from the ladderlike proximity effect between a “weak superconductor” with preformed bosonic pairs (here, a single-chain Luther-Emery liquid with superconducting correlations that decay approximately as (formula presented) and a Fermi gas with unpaired fermions. Carefully studying tunneling mechanism(s), we show that the boson-mediated Cooper pairing between remaining unpaired electrons results in a quasi-long-range superconductivity: Superconducting correlations decay very slowly as (formula presented) with (formula presented) This process is reminiscent of the coupling of fermions to preformed bosonic pairs introduced in the context of high-(formula presented) cuprates.