Magnetic impurity in a one-dimensional few-fermion system Rammelmüller, Lukas Huber, David Čufar, Matija Brand, Joachim Hammer, Hans-Werner Volosniev, Artem ; https://orcid.org/0000-0003-0393-5525 General Physics and Astronomy ddc:530 We present a numerical analysis of spin-1/2 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 s-wave 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. SciPost Foundation 2023 info:eu-repo/semantics/article doc-type:Article Article http://purl.org/coar/resource_type/c_2df8fbb1 https://research-explorer.ista.ac.at/record/13278 https://research-explorer.ista.ac.at/download/13278/13328 Rammelmüller L, Huber D, Čufar M, Brand J, Hammer H-W, Volosniev A. Magnetic impurity in a one-dimensional few-fermion system. <i>SciPost Physics</i>. 2023;14(1). doi:<a href="https://doi.org/10.21468/scipostphys.14.1.006">10.21468/scipostphys.14.1.006</a> eng info:eu-repo/semantics/altIdentifier/doi/10.21468/scipostphys.14.1.006 info:eu-repo/semantics/altIdentifier/issn/2542-4653 info:eu-repo/semantics/altIdentifier/wos/001000325800008 info:eu-repo/semantics/altIdentifier/arxiv/2204.01606 info:eu-repo/semantics/openAccess