Identification and Optimization of Accurate Spin Models for Open-Shell Carbon Ladders with Matrix Product States
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arXiv
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| Autori principali: | , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866911329782071296 |
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| author | Agirre, Andoni Frederiksen, Thomas Giedke, Geza Grass, Tobias |
| author_facet | Agirre, Andoni Frederiksen, Thomas Giedke, Geza Grass, Tobias |
| contents | Open-shell nanographenes offer a controlled setting to study correlated magnetism emerging from $π$-electron systems. We analyze oligo(indenoindene) molecules, non-bipartite carbon ladders whose tight-binding spectra feature a gapped, weakly dispersing manifold of quasi-zero modes, and show that their low-energy properties can be effectively mapped onto an interacting set of spin-1/2 degrees of freedom. Using Density Matrix Renormalization Group simulations of the full Fermi-Hubbard model, we obtain their excitation spectra, entanglement profiles, and spin-spin correlations. We then construct optimized delocalized fermionic modes that act as emergent spins and show that their interactions are well described by a frustrated $J_1$-$J_2$ Heisenberg chain. This effective description clarifies how spin degrees of freedom arise and interact in non-bipartite nanographene ladders, providing a compact and accurate representation of their correlated behavior. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_18695 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Identification and Optimization of Accurate Spin Models for Open-Shell Carbon Ladders with Matrix Product States Agirre, Andoni Frederiksen, Thomas Giedke, Geza Grass, Tobias Mesoscale and Nanoscale Physics Strongly Correlated Electrons Quantum Physics Open-shell nanographenes offer a controlled setting to study correlated magnetism emerging from $π$-electron systems. We analyze oligo(indenoindene) molecules, non-bipartite carbon ladders whose tight-binding spectra feature a gapped, weakly dispersing manifold of quasi-zero modes, and show that their low-energy properties can be effectively mapped onto an interacting set of spin-1/2 degrees of freedom. Using Density Matrix Renormalization Group simulations of the full Fermi-Hubbard model, we obtain their excitation spectra, entanglement profiles, and spin-spin correlations. We then construct optimized delocalized fermionic modes that act as emergent spins and show that their interactions are well described by a frustrated $J_1$-$J_2$ Heisenberg chain. This effective description clarifies how spin degrees of freedom arise and interact in non-bipartite nanographene ladders, providing a compact and accurate representation of their correlated behavior. |
| title | Identification and Optimization of Accurate Spin Models for Open-Shell Carbon Ladders with Matrix Product States |
| topic | Mesoscale and Nanoscale Physics Strongly Correlated Electrons Quantum Physics |
| url | https://arxiv.org/abs/2512.18695 |