Generic Finite Size Enhancement of Pairing in Mesoscopic Fermi Systems

TL;DR

This paper investigates how finite size effects enhance pairing interactions in mesoscopic Fermi systems like nuclei and metallic grains, explaining experimental data through surface effects within a BCS framework.

Contribution

It demonstrates a generic finite size enhancement mechanism for pairing in mesoscopic Fermi systems, emphasizing the role of surface effects across different physical systems.

Findings

Finite size enhances pairing correlations in mesoscopic systems.

Surface effects explain a significant part of the pairing enhancement.

The BCS approach remains valid for these finite systems.

Abstract

The finite size dependent enhancement of pairing in mesoscopic Fermi systems is studied under the assumption that the BCS approach is valid and that the two body force is size independent. Different systems are investigated such as superconducting metallic grains and films as well atomic nuclei. It is shown that the finite size enhancement of pairing in these systems is in part due to the presence of a surface which accounts quite well for the data of nuclei and explains a good fraction of the enhancement in Al grains.