Interaction effects on the itinerant ferromagnetism phase transition

Fuente: arXiv
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Main Authors: Pera, Jordi, Casulleras, Joaquim, Boronat, Jordi
Format: Preprint
Published: 2024
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author Pera, Jordi
Casulleras, Joaquim
Boronat, Jordi
author_facet Pera, Jordi
Casulleras, Joaquim
Boronat, Jordi
contents Itinerant ferromagnetism is one of the most studied quantum phase transitions, the transition point and the nature of this phase transition being widely discussed. In dilute Fermi liquids, this analysis has been carried out up to second-order in the gas parameter, where the results for any spin degeneracy are universal in terms of only the s-wave scattering length $a_0$. We extend this analysis to third-order where energies depend, not only on $a_0$, but also on the s-wave effective range $r_0$ and the p-wave scattering length $a_1$. The introduction in the theory of these new parameters changes the transition point, with respect to the second-order estimation, and also can modify the nature of the phase transition itself. We analyze these interaction effects on the phase transition for different spin values. The emerging phase diagram shows that the type of ferromagnetic transition changes dramatically as a function of $r_0$ and $a_1$ and, importantly, that this classification is not solely determined by the spin value, as happens at second order.
format Preprint
id arxiv_https___arxiv_org_abs_2407_14137
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Interaction effects on the itinerant ferromagnetism phase transition
Pera, Jordi
Casulleras, Joaquim
Boronat, Jordi
Quantum Gases
Strongly Correlated Electrons
Itinerant ferromagnetism is one of the most studied quantum phase transitions, the transition point and the nature of this phase transition being widely discussed. In dilute Fermi liquids, this analysis has been carried out up to second-order in the gas parameter, where the results for any spin degeneracy are universal in terms of only the s-wave scattering length $a_0$. We extend this analysis to third-order where energies depend, not only on $a_0$, but also on the s-wave effective range $r_0$ and the p-wave scattering length $a_1$. The introduction in the theory of these new parameters changes the transition point, with respect to the second-order estimation, and also can modify the nature of the phase transition itself. We analyze these interaction effects on the phase transition for different spin values. The emerging phase diagram shows that the type of ferromagnetic transition changes dramatically as a function of $r_0$ and $a_1$ and, importantly, that this classification is not solely determined by the spin value, as happens at second order.
title Interaction effects on the itinerant ferromagnetism phase transition
topic Quantum Gases
Strongly Correlated Electrons
url https://arxiv.org/abs/2407.14137