{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"c60451a85d8cdd36cddee9a8db04e2f7066f75ab91cf1532d668eabba9049871","created":"2026-10-03T07:17:59Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"55aafcc44d1d69a093628886a24e6229b40e33d63113ee1447a4a3a21cea90e8","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"identification","assisted_by":[],"external_id":"cm.frustrated-heisenberg.spin-nematic-observation","kind":"well-posed","literature_status":"open","n":"1","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 LiCuVO4 near saturation) or a spin-1 magnet with bound two-magnon states (candidate Na2BaNi(PO4)2), demonstrate quadrupolar order $\\langle S^{+}_{i}S^{+}_{j}\\rangle != 0$ 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":null,"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 LiCuVO4 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":"6b18b6294fc58cb8af2a2e06f7fa3f96d6f9c597e8ea928061976871624c524e"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"1c457cb8b21a0742cec6160cde606246e46090526e290aef0775d712aa10a27c","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"aaf07a88583b73d12e61deac84d3c3d7ec66cedd99576be52bddb646dfc14ccd","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"U4-M74gHPFnVDmN4jlYKEFHmQXiDI-z2IBTefo5RF8TzYKdr3CIpv6I8OUyfWEmFaNrjBZ678fp47G3fWYS2BA"},"schema":"pubphys.envelope/1"},"record_hash":"1c457cb8b21a0742cec6160cde606246e46090526e290aef0775d712aa10a27c","leaf_index":1001}