Rammelmüller LHuber DČufar MBrand JHammer H-WVolosniev AG2024-08-052024-08-052023-01-24Rammelmüller L, Huber D, Čufar M, Brand J, Hammer HW, Volosniev AG. (2023). Magnetic impurity in a one-dimensional few-fermion system. SciPost Physics. 14. 1.https://mro.massey.ac.nz/handle/10179/71189We present a numerical analysis of spin- ½ fermions in a one-dimensional harmonic potential in the presence of a magnetic point-like impurity at the center of the trap. The model represents a few-body analogue of a magnetic impurity in the vicinity of an swave superconductor. Already for a few particles we find a ground-state level crossing between sectors with different fermion parities. We interpret this crossing as a few-body precursor of a quantum phase transition, which occurs when the impurity “breaks” a Cooper pair. This picture is further corroborated by analyzing density-density correlations in momentum space. Finally, we discuss how the system may be realized with existing cold-atoms platforms.(c) 2023 The Author/sCC BY 4.0https://creativecommons.org/licenses/by/4.0/Journal article10.21468/SciPostPhys.14.1.0062542-4653journal-article006