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arXiv · 2204.01606

Magnetic impurity in a one-dimensional few-fermion system

Lukas Rammelmüller·David Huber·Matija Čufar·Joachim Brand·Hans-Werner Hammer·Artem G. Volosniev
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Abstract

We present a numerical analysis of spin-$\frac{1}{2}$ 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.

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Lukas Rammelmüller, David Huber, Matija Čufar, Joachim Brand, Hans-Werner Hammer, Artem G. Volosniev. 2022-04-04. Magnetic impurity in a one-dimensional few-fermion system. https://doi.org/10.21468/scipostphys.14.1.006

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