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| Main Authors: | , , , , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2508.08410 |
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| _version_ | 1866911631423832064 |
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| author | Sharma, Prakash Peng, Yang Sheng, Donna N. Changlani, Hitesh J. Wang, Yao |
| author_facet | Sharma, Prakash Peng, Yang Sheng, Donna N. Changlani, Hitesh J. Wang, Yao |
| contents | We investigate the Nagaoka-Thouless (NT) ferromagnetic instability in the strongly interacting $t$-$t'$ Hubbard model by continuously breaking particle-hole symmetry on a tunable square-triangular lattice geometry. We use an analytic approach to show that the fully spin-polarized state becomes unstable to a metastable spin-polaron when the kinetic frustration $t'/t$ exceeds a critical, dimension-dependent value. Large-scale density matrix renormalization group simulations reveal a quantum phase transition from the NT ferromagnet to a spiral spin-density wave, which evolves continuously into the Haerter-Shastry antiferromagnet in the large-frustration limit. Remarkably, this transition remains robust at low but finite hole density, making it accessible in cold-atom and moiré Hubbard platforms under strong interactions. A variational analysis further captures the instability mechanism at finite density via frustration-induced magnon band deformation. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2508_08410 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Instability of Nagaoka State and Quantum Phase Transition via Kinetic Frustration Control Sharma, Prakash Peng, Yang Sheng, Donna N. Changlani, Hitesh J. Wang, Yao Strongly Correlated Electrons We investigate the Nagaoka-Thouless (NT) ferromagnetic instability in the strongly interacting $t$-$t'$ Hubbard model by continuously breaking particle-hole symmetry on a tunable square-triangular lattice geometry. We use an analytic approach to show that the fully spin-polarized state becomes unstable to a metastable spin-polaron when the kinetic frustration $t'/t$ exceeds a critical, dimension-dependent value. Large-scale density matrix renormalization group simulations reveal a quantum phase transition from the NT ferromagnet to a spiral spin-density wave, which evolves continuously into the Haerter-Shastry antiferromagnet in the large-frustration limit. Remarkably, this transition remains robust at low but finite hole density, making it accessible in cold-atom and moiré Hubbard platforms under strong interactions. A variational analysis further captures the instability mechanism at finite density via frustration-induced magnon band deformation. |
| title | Instability of Nagaoka State and Quantum Phase Transition via Kinetic Frustration Control |
| topic | Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2508.08410 |