{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"1efe2d2d79457c76bb622f44bc3e3f633a27cb77746b162df08af684a7725a51","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":["ai:gpt-5.5"],"kind":"seed"},"parents":["1c457cb8b21a0742cec6160cde606246e46090526e290aef0775d712aa10a27c","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"a02a42dbc95a98ab0daa0d4816f7562145cad07d0e4da1fc9fd04327b9121460","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"identification","assisted_by":["ai:gpt-5.5"],"external_id":"cm.frustrated-heisenberg.spin-nematic-observation","kind":"well-posed","literature_status":"open","n":"2","parents":[],"plain":"In a spin-nematic phase the spins pair up so that no single spin points anywhere on average, yet the pairs share a common axis. Theory predicts it near magnetic saturation in several frustrated magnets, but no experiment has measured this hidden pair order directly.","posed_since":"","precise":"In a frustrated J1-J2 magnet with J1 < 0 (candidate $\\mathrm{LiCuVO_4}$ near saturation) or a spin-1 magnet with bound two-magnon states (candidate Na2BaNi(PO4)2), demonstrate quadrupolar order $\\langle S^{+}_{i}S^{+}_{j}\\rangle \\ne 0$ with $\\langle S_{i}\\rangle=0$ using a direct probe (resonant x-ray scattering, NMR lineshape and relaxation, or two-magnon bound-state spectroscopy). An answer is a material and field range with a measured quadrupolar order parameter.","problem_ref":"1c457cb8b21a0742cec6160cde606246e46090526e290aef0775d712aa10a27c","references":"","settled_by":"A measurement of long-range quadrupolar order or a two-magnon condensate together with absence of dipolar order in the same field window.","status_note":"Evidence in $\\mathrm{LiCuVO_4}$ near saturation remains indirect (NMR, magnetization, magnetostriction); condensation of a two-magnon bound state was reported in spin-1 Na2BaNi(PO4)2 (Sheng et al., Research Square preprint 2024) without a direct measurement of the quadrupolar order parameter.","title":"Direct observation of a spin-nematic phase in a magnet","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"d57a7c32bb5cd63d09602dacac6ff902153e6fc06eea976bf7e9d15f58954b02","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"7c50fd6131959131ec35193938a8ee0da6de585de30e48190bd9207421b2e405","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"7aHVHOA6FxAk9SeG1fqkYpxro7cAM4JA8SnwbyIA16qCSKgwN6W3VcImykPQDRVM9rm-0FmZm3MvPVWO1T-QDQ"},"schema":"pubphys.envelope/1"},"record_hash":"d57a7c32bb5cd63d09602dacac6ff902153e6fc06eea976bf7e9d15f58954b02","leaf_index":2818}