Neutral weak currents in nucleon superfluid Fermi liquids: Larkin-Migdal and Leggett approaches

TL;DR

This paper compares two theoretical approaches, Larkin-Migdal and Leggett, to calculate neutrino emission in superfluid nucleon Fermi liquids, showing they produce equivalent results for pair breaking and formation processes.

Contribution

It clarifies the relationship between the Larkin-Migdal and Leggett methods and demonstrates their equivalence in calculating neutrino emissivity in superfluid Fermi liquids.

Findings

Both approaches yield the same expression for neutrino emissivity.

The paper explains key differences and similarities of the two methods.

Results support the validity of using either approach for superfluid Fermi liquids.

Abstract

Neutrino emission in processes of breaking and formation of nucleon Cooper pairs is calculated in the framework of the Larkin-Migdal and the Leggett approaches to the description of superfluid Fermi liquids at finite temperatures. We explain peculiarities of both approaches and explicitly demonstrate that they lead to the same expression for the emissivity in pair breaking and formation processes.