Spin-resolved Mott crossover and entanglement in the half-filled Hubbard model
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arXiv
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| Format: | Preprint |
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2025
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| author | Equbal, Md Fahad Ahsan, M. A. H. |
| author_facet | Equbal, Md Fahad Ahsan, M. A. H. |
| contents | We investigate the interaction-driven reorganization of spin and charge correlations in finite Hubbard clusters using exact diagonalization. Focusing on half-filled and lightly doped square lattices, we analyze spin-resolved charge-gaps, local observables, two-point correlation functions, entanglement measures, principal component analysis (PCA) of correlation matrices and quantum-geometry-based distance metrics. At half-filling, we observe the emergence of a robust Mott gap whose spin-dependent component is controlled by the effective exchange energy scale J~4t^2/U at strong coupling, confirming that residual spin dynamics govern the separation between the lowest-spin and the next higher-spin charge excitation channels. Distinct cluster geometries and boundary conditions reveal how spin-singlet versus finite-spin ground-state influence charge and spin responses. Upon one-hole doping, the spin-resolved charge-gaps collapses, indicating restored compressibility and metallic behavior. PCA and quantum-geometry-based analysis provide complementary data-driven and wavefunction-based perspectives on correlation-driven Mott crossover phenomena. Our results demonstrate that finite-size Hubbard clusters exhibit clear signatures of the Mott physics, spin-charge interplay and emergent exchange energy scales, offering a unified microscopic picture of interaction-induced electronic reorganization. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_00613 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Spin-resolved Mott crossover and entanglement in the half-filled Hubbard model Equbal, Md Fahad Ahsan, M. A. H. Strongly Correlated Electrons We investigate the interaction-driven reorganization of spin and charge correlations in finite Hubbard clusters using exact diagonalization. Focusing on half-filled and lightly doped square lattices, we analyze spin-resolved charge-gaps, local observables, two-point correlation functions, entanglement measures, principal component analysis (PCA) of correlation matrices and quantum-geometry-based distance metrics. At half-filling, we observe the emergence of a robust Mott gap whose spin-dependent component is controlled by the effective exchange energy scale J~4t^2/U at strong coupling, confirming that residual spin dynamics govern the separation between the lowest-spin and the next higher-spin charge excitation channels. Distinct cluster geometries and boundary conditions reveal how spin-singlet versus finite-spin ground-state influence charge and spin responses. Upon one-hole doping, the spin-resolved charge-gaps collapses, indicating restored compressibility and metallic behavior. PCA and quantum-geometry-based analysis provide complementary data-driven and wavefunction-based perspectives on correlation-driven Mott crossover phenomena. Our results demonstrate that finite-size Hubbard clusters exhibit clear signatures of the Mott physics, spin-charge interplay and emergent exchange energy scales, offering a unified microscopic picture of interaction-induced electronic reorganization. |
| title | Spin-resolved Mott crossover and entanglement in the half-filled Hubbard model |
| topic | Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2512.00613 |