Backert TGBrauneis FČufar MBrand JHammer H-WVolosniev AG2025-11-302025-07-03Backert TG, Brauneis F, Čufar M, Brand J, Hammer HW, Volosniev AG. (2025). Effective Theory for Strongly Attractive One-Dimensional Fermions. Physical Review Letters. 135. 4. (pp. 040401-).1079-7114https://mro.massey.ac.nz/handle/10179/73865We study a one-dimensional system of two-component fermions in the limit of strong attractive particle-particle interactions. First, we analyze scattering in the corresponding few-body problem, which is analytically solvable via Bethe ansatz. This allows us to engineer effective interactions between the system's effective degrees of freedom: fermions and bosonic dimers (tightly bound pairs of fermions). We argue that, although these interactions are strong, the resulting effective problem can be mapped onto a weakly interacting one, paving the way for the use of perturbation theory. This finding simplifies studies of many-fermion systems under confinement that are beyond reach of state-of-the-art numerical methods. We illustrate this statement by considering an impurity atom in a Fermi gas.CC BY 4.0(c) 2024 The Author/shttps://creativecommons.org/licenses/by/4.0/Journal article10.1103/8mnc-x42q1079-7114journal-article040401-040401