On the Weakness of Short-Range Interactions in Fermi Gases

TL;DR

This paper rigorously justifies when ultracold Fermi gases with short-range interactions can be approximated as free particles, despite strong pairing effects, clarifying the conditions under which this simplification holds.

Contribution

It provides a rigorous framework for understanding when short-range interactions in Fermi gases can be neglected, advancing theoretical insights into ultracold quantum gases.

Findings

Identification of conditions where short-range interactions can be ignored

Rigorous mathematical description of many-particle Schrödinger operators

Clarification of the approximation validity in strongly paired regimes

Abstract

Ultracold quantum gases of equal spin fermions with short range interactions are often considered free even in the presence of strongly binding spin-up-spin-down pairs. We describe a large class of many-particle Schr\"odinger operators with short-range pair interactions, where this approximation can be justified rigorously.