Thermal signatures of pairing correlations in nuclei and nano-scale metallic grains

TL;DR

This paper explores thermal signatures of pairing correlations in nuclei and nano-scale metallic grains, especially in regimes where traditional BCS theory fails due to large fluctuations.

Contribution

It analyzes how pairing correlations manifest thermally in regimes where BCS theory breaks down, bridging the understanding between bulk and fluctuation-dominated systems.

Findings

Pairing signatures persist despite large fluctuations.

Thermal behavior differs from bulk BCS predictions.

Insights into crossover regimes of pairing correlations.

Abstract

Atomic nuclei and nano-scale metallic grains are in the crossover regime of pairing correlations between the bulk limit, where the Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity is valid, and the fluctuation-dominated regime, where BCS theory breaks down. In this fluctuation-dominated regime, the pairing gap is comparable to or smaller than the single-particle mean level spacing. We discuss thermal signatures of pairing correlations in nuclei and ultra-small metallic grains that survive despite the large fluctuations of the pairing field.