{
  "abstract": "We derive the effective action of temporal metamaterials up to first order in spatial derivatives through a multiscale analysis of the electromagnetic Lagrangian density. We show that the first-order spatial correction gives rise to an effective bianisotropic coupling tensor that is odd in the wavevector $\\mathbf{k}$. Remarkably, chiral, pseudochiral, and omega-type bianisotropic responses emerge as distinct directional manifestations of a single nonlocal coupling tensor, even when the underlying electric and magnetic response tensors remain symmetric. Furthermore, we establish a framework for analyzing Lorentz reciprocity based on the Hessian of the effective action. We demonstrate that Lorentz reciprocity is preserved in the presence of omega-type coupling but is broken when chiral or pseudochiral coupling emerges. This nonreciprocity manifests as the unidirectional rotations of normalized Stokes vectors incurred by Floquet-engineered chirality and pseudochirality.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.31022",
  "author_total": 2,
  "authors": [
    {
      "name": "Neng Wang"
    },
    {
      "name": "Guo Ping Wang"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/2ktgkbrdypg1p.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.31022",
  "fulltext_url": null,
  "id": "2ktgkbrdypg1p",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.31022",
  "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",
      "2504|Metamaterials and Metasurfaces Applications"
    ]
  ],
  "openalex": "W7223349463",
  "pdf_url": "https://arxiv.org/pdf/2610.31022",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-22",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/2ktgkbrdypg1p.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:34:34Z",
      "native_id": "2610.31022",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.31022"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:physics.optics",
      "subfield": "optics-photonics"
    }
  ],
  "title": "Effective-action formulation of $\\mathbf{k}$-odd bianisotropy and unidirectional polarization rotation in nonlocal temporal metamaterials",
  "title_text": "Effective-action formulation of k-odd bianisotropy and unidirectional polarization rotation in nonlocal temporal metamaterials",
  "type": "preprint",
  "updated_at": "2026-10-30T12:34:34Z",
  "url": "https://research.draconitic.com/paper/2ktgkbrdypg1p",
  "venue": "arXiv",
  "versions": []
}