Scattering length for composite bosons in the BCS-BEC crossover

TL;DR

This paper calculates the scattering length between composite bosons formed from fermion pairs in the BCS-BEC crossover, relevant for ultracold atomic gases and recent experimental developments.

Contribution

It provides a specific calculation of the boson-boson scattering length in the strong-coupling limit of the BCS-BEC crossover, aiding understanding of ultracold molecular gases.

Findings

Calculated boson-boson scattering length in the BCS-BEC crossover

Relevance to ultracold molecule formation experiments

Provides theoretical support for experimental observations

Abstract

The present manuscript concerns the calculation of the boson-boson scattering length for the composite bosons that form as bound-fermion pairs in the strong-coupling limit of the BCS-BEC crossover. The material presented in this manuscript was already published as a part of a longer paper on the BCS-BEC crossover problem (P. Pieri and G.C. Strinati, Phys. Rev. B 61, 15370 (2000)). Given the recent experimental advances on the formation of ultracold bosonic molecules from a Fermi gas of atoms by a Feshbach resonance, the calculation of the boson-boson scattering length has now become of particular interest. The present short version of the above paper could thus be helpful to the scientific community working on ultracold atomic gases. Accordingly, the present manuscript is intended for circulation as a preprint only.