[2608.14460] Learning Spin Hamiltonians from Terahertz Two-Dimensional Coherent Spectroscopy Skip to main content Search Submit Donate Log in Search arXiv Press Enter to search · Advanced search Physics > Computational Physics arXiv:2608.14460 (physics) [Submitted on 14 Aug 2026] Title: Learning Spin Hamiltonians from Terahertz Two-Dimensional Coherent Spectroscopy Authors: Martin Mootz , Chuankun Huang , Liang Luo , Jigang Wang , Yong-Xin Yao View a PDF of the paper titled Learning Spin Hamiltonians from Terahertz Two-Dimensional Coherent Spectroscopy, by Martin Mootz and 4 other authors View PDF HTML (experimental) Abstract: Effective Hamiltonians connect microscopic interactions to measurable collective behavior in quantum materials, but determining their parameters directly from experiment remains a challenging inverse problem. We introduce a supervised machine-learning framework that infers Hamiltonian parameters from nonlinear terahertz two-dimensional coherent spectra. A calibrated forward model generates spectra from candidate Hamiltonians, a common preprocessing pipeline maps simulated and experimental spectra into the same representation, and a neural network learns the inverse map from spectral fingerprints to microscopic parameters. We demonstrate the approach for rare-earth orthoferrites using a two-sublattice Landau--Lifshitz--Gilbert spin model with exchange, Dzyaloshinskii--Moriya interaction, anisotropies, and damping. Synthetic benchmarks show that nonlinear spectra encode parameters beyond those fixed by the linear response, with inference accuracy tracking the physical spectral sensitivity and robustness against noise improved by using multiple inter-pulse delays. Applied to experimental THz-2DCS data from Sm$_{0.4}$Er$_{0.6}$FeO$_3$, the inferred parameters yield physically reasonable forward simulations, while remaining discrepancies identify limitations of the reduced model. These results establish THz-2DCS as a data-rich platform for effective-Hamiltonian inference and model refinement, enabling experimentally driven identification of microscopic interactions while providing a foundation for understanding, predicting, and ultimately controlling the emergent properties of quantum materials. Subjects: Computational Physics (physics.comp-ph) ; Strongly Correlated Electrons (cond-mat.str-el); Optics (physics.optics) Cite as: arXiv:2608.14460 [physics.comp-ph] (or arXiv:2608.14460v1 [physics.comp-ph] for this version) https://doi.org/10.48550/arXiv.2608.14460 Focus to learn more arXiv-issued DOI via DataCite Submission history From: Martin Mootz [ view email ] [v1] Fri, 14 Aug 2026 16:42:23 UTC (1,865 KB) Full-text links: Access Paper: View a PDF of the paper titled Learning Spin Hamiltonians from Terahertz Two-Dimensional Coherent Spectroscopy, by Martin Mootz and 4 other authors View PDF HTML (experimental) TeX Source view license Current browse context: physics.comp-ph < prev | next > new | recent | 2026-08 Change to browse by: cond-mat cond-mat.str-el physics physics.optics References & Citations NASA ADS Google Scholar Semantic Scholar export BibTeX citation Loading... BibTeX formatted citation × loading... 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