Probable observation of the nuclear Cooper pair mean square radius in superfluid nuclei

TL;DR

This paper discusses the potential observation of the nuclear Cooper pair mean square radius in superfluid nuclei, linking experimental studies of Cooper pairs in nuclei to phenomena like the Josephson effect.

Contribution

It presents the first experimental estimate of the nuclear coherence length based on recent studies of Cooper pair transfer in heavy ion collisions.

Findings

Experimental input suggests a measurable nuclear coherence length.

Evidence supports the nuclear analogue of the Josephson effect.

Results extend understanding of superfluidity in atomic nuclei.

Abstract

The phenomenon of low-temperature superconductivity is intimately associated with the condensation of weakly bound, very extended, strongly overlapping Cooper pairs, and systematic experimental studies of the associated mean square radius (coherence length) have been made. While the extension of BCS theory to the atomic nucleus has been successful beyond expectation, to our knowledge, no measurement of the nuclear coherence length (expected to be much larger than nuclear dimensions) has been reported in the literature. Recent studies of Cooper pair transfer across a Josephson-like junction, transiently established in a heavy ion collision between superfluid nuclei, have likely changed the situation, providing the experimental input for a quantitative estimate of the nuclear coherence length, as well as the basis for a nuclear analogue of the (ac) Josephson effect.