Magnetic impurity in a one-dimensional few-fermion system

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

doi:10.21468/SciPostPhys.14.1.006

SciPost Physics

Magnetic impurity in a one-dimensional few-fermion system

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

SciPost Phys. 14, 006 (2023) · published 24 January 2023

doi: 10.21468/SciPostPhys.14.1.006
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Abstract

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

TY  - JOUR
PB  - SciPost Foundation
DO  - 10.21468/SciPostPhys.14.1.006
TI  - Magnetic impurity in a one-dimensional few-fermion system
PY  - 2023/01/24
UR  - https://scipost.org/SciPostPhys.14.1.006
JF  - SciPost Physics
JA  - SciPost Phys.
VL  - 14
IS  - 1
SP  - 006
A1  - Rammelmüller, Lukas
AU  - Huber, David
AU  - Čufar, Matija
AU  - Brand, Joachim
AU  - Hammer, Hans-Werner
AU  - Volosniev, Artem G.
AB  - We present a numerical analysis of spin-$\tfrac{1}{2}$ 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.
ER  -

@Article{10.21468/SciPostPhys.14.1.006,
	title={{Magnetic impurity in a one-dimensional few-fermion system}},
	author={Lukas Rammelmüller and David Huber and Matija Čufar and Joachim Brand and Hans-Werner Hammer and Artem G. Volosniev},
	journal={SciPost Phys.},
	volume={14},
	pages={006},
	year={2023},
	publisher={SciPost},
	doi={10.21468/SciPostPhys.14.1.006},
	url={https://scipost.org/10.21468/SciPostPhys.14.1.006},
}

Cited by 6

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¹ ² Lukas Rammelmüller,
³ David Huber,
⁴ Matija Čufar,
⁴ Joachim Brand,
³ ⁵ Hans-Werner Hammer,
⁶ Artem G. Volosniev

Funders for the research work leading to this publication

Bundesministerium für Bildung und Forschung / Federal Ministry of Education and Research [BMBF]
Deutsche Forschungsgemeinschaft / German Research FoundationDeutsche Forschungsgemeinschaft [DFG]
FP7 Seventh Framework Programme (FP7) (through Organization: European Commission [EC])
Horizon 2020 (through Organization: European Commission [EC])
Marsden Fund (through Organization: Royal Society Te Apārangi / Royal Society of New Zealand)