Ferrimagnetism of ultracold fermions in a multiband Hubbard system.
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| Title: | Ferrimagnetism of ultracold fermions in a multiband Hubbard system. |
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| Authors: | Lebrat, Martin (AUTHOR), Kale, Anant (AUTHOR), Kendrick, Lev Haldar (AUTHOR), Xu, Muqing (AUTHOR), Gang, Youqi (AUTHOR), Nikolaenko, Alexander (AUTHOR), Bonetti, Pietro M. (AUTHOR), Sachdev, Subir (AUTHOR), Greiner, Markus (AUTHOR) |
| Source: | Science. 5/7/2026, Vol. 392 Issue 6798, p612-616. 5p. |
| Subjects: | Ferrimagnetism, Hubbard model, Quantum gases, Spin polarization, Optical lattices |
| Abstract: | Strongly correlated materials feature multiple electronic orbitals, which are crucial to accurately understanding their many-body properties. In such multiband models, quantum interference can lead to flat energy bands with large degeneracy that gives rise to itinerant magnetic phases. We report on signatures of a ferrimagnetic state realized in a Lieb lattice with ultracold fermions, characterized by antialigned magnetic moments with antiferromagnetic correlations, and concomitant with a finite spin polarization. The signatures remain robust when increasing repulsive interactions from the weakly interacting to the Heisenberg regime and emerge when continuously tuning the lattice unit cell from a square to a Lieb geometry. Our flexible approach paves the way toward exploring exotic phases, such as quantum spin liquids in kagome lattices and heavy fermion behavior in Kondo models. Editor's summary: Copper oxide superconductors and other strongly interacting systems are thought to be described by the Hubbard model. This model, which accounts for particle hopping and interactions, can be simulated using cold atoms in optical lattices. However, incorporating multiple energy bands, which is thought to be important for an accurate description of the physics, is tricky. Lebrat et al. performed the quantum simulation of a multiband Hubbard model using fermionic lithium-6 atoms in an optical Lieb lattice, which can be viewed as a simplified description of the copper oxide lattice. Because two the sublattices constituting the Lieb lattice have an unequal number of sites, this system is expected to exhibit ferrimagnetism, which the researchers observed through site-resolved measurements of spin. —Jelena Stajic [ABSTRACT FROM AUTHOR] |
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| Database: | Psychology and Behavioral Sciences Collection |
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| Abstract: | Strongly correlated materials feature multiple electronic orbitals, which are crucial to accurately understanding their many-body properties. In such multiband models, quantum interference can lead to flat energy bands with large degeneracy that gives rise to itinerant magnetic phases. We report on signatures of a ferrimagnetic state realized in a Lieb lattice with ultracold fermions, characterized by antialigned magnetic moments with antiferromagnetic correlations, and concomitant with a finite spin polarization. The signatures remain robust when increasing repulsive interactions from the weakly interacting to the Heisenberg regime and emerge when continuously tuning the lattice unit cell from a square to a Lieb geometry. Our flexible approach paves the way toward exploring exotic phases, such as quantum spin liquids in kagome lattices and heavy fermion behavior in Kondo models. Editor's summary: Copper oxide superconductors and other strongly interacting systems are thought to be described by the Hubbard model. This model, which accounts for particle hopping and interactions, can be simulated using cold atoms in optical lattices. However, incorporating multiple energy bands, which is thought to be important for an accurate description of the physics, is tricky. Lebrat et al. performed the quantum simulation of a multiband Hubbard model using fermionic lithium-6 atoms in an optical Lieb lattice, which can be viewed as a simplified description of the copper oxide lattice. Because two the sublattices constituting the Lieb lattice have an unequal number of sites, this system is expected to exhibit ferrimagnetism, which the researchers observed through site-resolved measurements of spin. —Jelena Stajic [ABSTRACT FROM AUTHOR] |
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| ISSN: | 00368075 |
| DOI: | 10.1126/science.adq2411 |
