{
  "abstract": "Quantum materials host a rich spectrum of low-energy collective excitations- phonons, magnons, plasmons, polaritons, and Higgs modes- that fundamentally govern their emergent properties, but remain inaccessible to conventional linear THz spectroscopy when nonlinear pathways overlap or non-perturbative dynamics emerge. Terahertz two-dimensional coherent spectroscopy (THz-2DCS), realized through phase-stable high-field THz pulse sequences, directly resolves this challenge by delivering phase-resolved multidimensional spectra that uniquely disentangle coherent intraband nonlinear quantum dynamics from incoherent backgrounds. Here, we establish a unified theoretical framework by using density-matrix formalism combined with the optical Bloch equations, from which nonlinear pathways are systematically derived and visualized on the Bloch sphere. This framework provides insight into low-energy nonlinear dynamics exhibiting homogeneous or inhomogeneous broadening depending on the scattering mechanism, enabling the interpretation of nonlinear signals in both the perturbative regime, described by a susceptibility expansion, and the non-perturbative regime. Building on this foundation, we comprehensively survey THz-2DCS investigations of nonlinear plasmon, phonon, magnon, and polariton. Finally, we outline future opportunities, including integration with optical-pump THz-probe platforms for nonequilibrium quantum control.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.16623",
  "author_total": 3,
  "authors": [
    {
      "name": "Se Jin Park"
    },
    {
      "name": "In Hyeok Choi"
    },
    {
      "name": "Jeong Woo Han"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/4caahak62qjzk.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.16623",
  "fulltext_url": null,
  "id": "4caahak62qjzk",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.16623",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "physics.optics"
    ],
    [
      "openalex",
      "2208|Terahertz technology and applications"
    ]
  ],
  "openalex": "W7213416704",
  "pdf_url": "https://arxiv.org/pdf/2609.16623",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-15",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/4caahak62qjzk.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:41Z",
      "native_id": "2609.16623",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.16623"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:physics.optics",
      "subfield": "optics-photonics"
    }
  ],
  "title": "Terahertz two-dimensional coherent spectroscopy: unlocking coherent quantum intraband nonlinear dynamics",
  "title_text": "Terahertz two-dimensional coherent spectroscopy: unlocking coherent quantum intraband nonlinear dynamics",
  "type": "preprint",
  "updated_at": "2026-10-30T12:21:41Z",
  "url": "https://research.draconitic.com/paper/4caahak62qjzk",
  "venue": "arXiv",
  "versions": []
}