{"schema":"pubphys.bundle/1","record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"1c997727e86347c0327036b7479647c689e1f5e6e72fe6c02ed682ea56f99caa","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":["ai:gpt-5.5"],"kind":"seed"},"parents":["8484e65efeb2c9a35215af78d85384dea72c0a764a56f52bf811c979591f3ea0","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"9739a2673bc87f6d8284d8cc71bb4bf6fb9fb1b8b140757112de512ad0455901","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"identification","assisted_by":["ai:gpt-5.5"],"external_id":"cm.heavy-fermions.uru2si2-hidden-order","kind":"well-posed","literature_status":"contested","n":"2","parents":[],"plain":"Below 17.5 K, $\\mathrm{URu_2Si_2}$ enters an ordered phase that releases a large amount of entropy, yet nearly forty years of experiments have not identified what orders.","posed_since":"1985","precise":"Identify the order parameter of the phase below $T_{\\mathrm{HO}} = 17.5\\ \\mathrm{K}$ in $\\mathrm{URu_2Si_2}$, which has no ordered magnetic moment of matching size and doubles the unit cell along c (wavevector $(0,0,1)$). Candidates include higher-rank multipoles (hexadecapole, dotriacontapole), hastatic order and chirality density waves. An answer gives the symmetry (irreducible representation) and microscopic character, confirmed by a probe that couples directly to it (resonant x-ray scattering, Raman, NMR).","problem_ref":"8484e65efeb2c9a35215af78d85384dea72c0a764a56f52bf811c979591f3ea0","references":"","settled_by":"A direct detection of the proposed order parameter whose temperature dependence follows $T_{\\mathrm{HO}}$ and vanishes under pressure-induced antiferromagnetism.","status_note":"Raman data (2015) show an $A_2g$ mode suggesting chirality-density-wave order, while reports of in-plane fourfold symmetry breaking disagree between probes.","title":"What is the order parameter of hidden order in $\\mathrm{URu_2Si_2}$?","topic_ref":null},"content_withheld":"false","files":[],"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"ddf0bbf01604d40d03be88b6b0c629c7793296d8dd5de7497a1dce0796e560a8","schema":"pubphys.attested/1"},"id_token":null,"id_token_withheld":"false","envelope":{"attested_hash":"c6ea849ddd657355404bba623ace919ca793800d986533bd495a4c0389431a1b","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"OwyxbW5XZc1tBjEgqFZPyXVqWUXGQxPsCh8fo4t_l1EUt88or4NkF0EXgxsA3BJ7ntraZKbAXIlj-PTzIqPnBQ"},"schema":"pubphys.envelope/1"},"ots":{"attested":["AE9wZW5UaW1lc3RhbXBzAABQcm9vZgC_ieLohOiSlAEIxuqEnd1lc1VAS7piOs6RnKeTgA2YZTO9SVpMA4lDGhvxIMbh0MwB2LsR4YByjPtWPFgtKdqfLjk-Ktcf0Jddcru1CPAgQI31FQ65FwlbYh7cDbFEH0PegkJDIVdqcprp04rhxV8I8SAEcWSJauwUnbOIaebVrf76PTZbXo9U0VsX1pEtHXOyXwjwII7FYL4ACVlQPL-AQ34Wc4Pnfej5QViZXdCJIzRjXv5mCPEgC4UBUk2r3p6N5ePHELIcf74Fc-UaEHAyQbIol04HlkII8CDgwxexIxmrpOhu1lJVX868FkmRS21yEDi-6oEm4lCQ5gjwIFN5Bsm0GrOfAbeKEdWABW0DwjhI5zX9zku3NWou5CmtCPAg5eqR4CU5l8kO1rB2qJB7mTDxO5KdiNtAiUft-v_2wc8I8CCSqAf0sn_1-kk9EDPXEZvjRff_ciLViVfMVybjDX1OsQjxID89HsXrUag9eRv04qSQX18D2ak5pxDN4H8m3_0Qkp84CPAg3mczMYDKOd7Nhf3ojA9ZvuTsN66Y1NnyYTp9j8GKQNwI8SCvAiiN-Hrv7IEejd8wdUihoozu5KOvpoBFJ0vg3UnGAQj_8Ajn9YmozHwo9QjwEJ46aM9ZDv3TdtqV3ZbRsNgI8SBOF8pILGf1kodr5MKmQs6Cd93joraGn3g6UPt_-kewPwjwIOG-gmM7bd_eR4AiDMNfluS3xvr7vicLR-sCBr5qtG2cCPAgrVNFrCoeQcCxhlmnE0BzHgR8HQpZAlfqzDDFzfWb8GUI8QRq0WWT8AjZJ2cF_c7k8ACD3-MNLvkMjiwraHR0cHM6Ly9ib2IuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZ_AI9ZMS1zxd7IEI8BDd00WgJZ0RncsC1Fyai_4aCPEgvxMFrnu7F05IW5INiraQ3OVEYMjNx6JfBxw1Q4jPLi4I8QRq0WWS8Ag2zxPAtI5JsP8Ag9_jDS75DI4uLWh0dHBzOi8vYWxpY2UuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZwjxIHAnv4KFFf4uiYEFJvLxiMxSyz8VowJP4roTfDD9h7bICPAgj5tgvbNF7mxSP4jGGE66ezUFRLnI4g1VTkvuV4VtCPAI8CCxlc1HuKORuHgn7DYIYcDhc4oo99OkTWBEvddBypoa7AjwIFcjjaF8kDNDYCZGaNISlRjvX-I7in-QNwsr4JYQbFJvCPAgnl0k4gs7LuY5i1umiHO-J7My3uBThLJUWQoY9LdVSrQI8SA6-Ft11_K_GqMNWYhkVsVqCFvXSYbp4S8JoLsLBnUzvgjxIBC8_mAE7JBP35SNxDBcG7joLJwURpMxdV2vSO64_jEOCPEge04Coj1xSi7CE8UwqiBGNhPyZ5QdD_YZwn-heSdObU4I8SBgdDSgr3VUx1j8m_pK7-OzMwwFgXeLy43ujffCv-hf5AjwIMl-PnAt4xjoBEVU4-nkyN0NKRa9AvX4kEMfllFyIJS9CPFZAQAAAAHz4rV-uwQFg02bVnEMUFgpIdGKjM4tWuID1kTVnrjisAAAAAAA_v___wJURAIAAAAAABYAFBFys2oc0-U-bYrC3VulGLzND5fbAAAAAAAAAAAiaiDwBHLTDgAICPEgMJIBYi46xOIuFDwzJ9nOx14ngW5HbglUf65ORpkoIYcICPAgHgGWEGCDHWgscwT92NOoJ7s-ezbPkyiWr2RnYZDC_dwICPAgtffMyyLu-MscJsDc0dzwGspwSrrmvVAnMNgsgWhHClgICPAgMUl1OfBDUwhp5VZjHwVA0nuz1F5HZTUJCHAnM1L1F3MICPAgStK7UWpnrUueV5EaE7uE0y6BLMp6EANmrbhrTqEBZu8ICPAg5LVW7IHtUL5mNOvPx1hOTfLMmqlQ7t9EFW-KDtrISIQICPAgABgXZ6upFU8qiDQKFtQFpqkjKwl0PsxM4JUjVLlDKbkICPAgEwb96FiOhjlbwI8GFZQ4a5GXwxs4bUdqVOMKrtBWV30ICPEgqBg-wp0c8CAPV9k6J7wIa9_GtQfpWmhpE1zqFZyi2pQICPAg2pZLTVPGJbriiz0UhMytYDVYAXOgQnWDcrMOewK9O8cICPEgxm3QwzbvT4siJzubQGnST67bWv-exYwSPP1KDi7CaUwICPEgm6udUudfjUaM0gUFTylKGDMypj7ptMTG0zmxd_T5yTcICPAgMpOInkjFCVp1pOZhfZnyPAl8hdWGmHzQcrGLgLwSKLgICAAFiJYNc9cZAQPzpjs"],"envelope":["AE9wZW5UaW1lc3RhbXBzAABQcm9vZgC_ieLohOiSlAEIf7fkATngZPkASSRU7ScuYhBPHComL0X0RSTlbDT2MJ_xIH-k4iXACC0ehw4kBs8HMsJLHFoWquXzbXTGtheC_6ssCPAgurlsWdMZ8zFSRZ1LOsZzVro7b6Q_rhXJdyNZcB78NfAI8SAgQyGKkSiNwaFUy1ayN1Qc1sslnktlkkdaVLWWJouwYAjxINbPiTvYTslpR1e6OCrARyg27qGyvvlQS3D_kGK847YpCPEgPyo_pyqLt5GwuyCfZAL-iCj1UkZNia7Ly0D8PPU9PH4I8CAGNtz83AQ9v5-gxKZQwTuf04yoihPFlPqicB12zVGvsgjwINcabnKDjMkLxRvsoaPCbX0K9J56jcSSW0dTiX8obtbECPEgC07znjc0bVDgPzONkw3aBXeRFcSLeM3BhuNQIWI6mKkI8CCCFfNrg2ZeB51PNa84j-z6Sin0AxT6aP9r7HupgUKbMwjxICknnLxa8xs8qmAdhtb0NnANbtwYyrlRTgqcMVLLl8ogCPEgHd9u6OIGCvUV12A1B1xdiOprSJ-4w0cqwfe7CzVX5HsI8CDQo_sIWZiWXaTGRSQBLmU-lHJKskYKqsjO1r02DhB8LAj_8Ajn9YmozHwo9QjwEJ46aM9ZDv3TdtqV3ZbRsNgI8SBOF8pILGf1kodr5MKmQs6Cd93joraGn3g6UPt_-kewPwjwIOG-gmM7bd_eR4AiDMNfluS3xvr7vicLR-sCBr5qtG2cCPAgrVNFrCoeQcCxhlmnE0BzHgR8HQpZAlfqzDDFzfWb8GUI8QRq0WWT8AjZJ2cF_c7k8ACD3-MNLvkMjiwraHR0cHM6Ly9ib2IuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZ_AI9ZMS1zxd7IEI8BDd00WgJZ0RncsC1Fyai_4aCPEgvxMFrnu7F05IW5INiraQ3OVEYMjNx6JfBxw1Q4jPLi4I8QRq0WWS8Ag2zxPAtI5JsP8Ag9_jDS75DI4uLWh0dHBzOi8vYWxpY2UuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZwjxIHAnv4KFFf4uiYEFJvLxiMxSyz8VowJP4roTfDD9h7bICPAgj5tgvbNF7mxSP4jGGE66ezUFRLnI4g1VTkvuV4VtCPAI8CCxlc1HuKORuHgn7DYIYcDhc4oo99OkTWBEvddBypoa7AjwIFcjjaF8kDNDYCZGaNISlRjvX-I7in-QNwsr4JYQbFJvCPAgnl0k4gs7LuY5i1umiHO-J7My3uBThLJUWQoY9LdVSrQI8SA6-Ft11_K_GqMNWYhkVsVqCFvXSYbp4S8JoLsLBnUzvgjxIBC8_mAE7JBP35SNxDBcG7joLJwURpMxdV2vSO64_jEOCPEge04Coj1xSi7CE8UwqiBGNhPyZ5QdD_YZwn-heSdObU4I8SBgdDSgr3VUx1j8m_pK7-OzMwwFgXeLy43ujffCv-hf5AjwIMl-PnAt4xjoBEVU4-nkyN0NKRa9AvX4kEMfllFyIJS9CPFZAQAAAAHz4rV-uwQFg02bVnEMUFgpIdGKjM4tWuID1kTVnrjisAAAAAAA_v___wJURAIAAAAAABYAFBFys2oc0-U-bYrC3VulGLzND5fbAAAAAAAAAAAiaiDwBHLTDgAICPEgMJIBYi46xOIuFDwzJ9nOx14ngW5HbglUf65ORpkoIYcICPAgHgGWEGCDHWgscwT92NOoJ7s-ezbPkyiWr2RnYZDC_dwICPAgtffMyyLu-MscJsDc0dzwGspwSrrmvVAnMNgsgWhHClgICPAgMUl1OfBDUwhp5VZjHwVA0nuz1F5HZTUJCHAnM1L1F3MICPAgStK7UWpnrUueV5EaE7uE0y6BLMp6EANmrbhrTqEBZu8ICPAg5LVW7IHtUL5mNOvPx1hOTfLMmqlQ7t9EFW-KDtrISIQICPAgABgXZ6upFU8qiDQKFtQFpqkjKwl0PsxM4JUjVLlDKbkICPAgEwb96FiOhjlbwI8GFZQ4a5GXwxs4bUdqVOMKrtBWV30ICPEgqBg-wp0c8CAPV9k6J7wIa9_GtQfpWmhpE1zqFZyi2pQICPAg2pZLTVPGJbriiz0UhMytYDVYAXOgQnWDcrMOewK9O8cICPEgxm3QwzbvT4siJzubQGnST67bWv-exYwSPP1KDi7CaUwICPEgm6udUudfjUaM0gUFTylKGDMypj7ptMTG0zmxd_T5yTcICPAgMpOInkjFCVp1pOZhfZnyPAl8hdWGmHzQcrGLgLwSKLgICAAFiJYNc9cZAQPzpjs"]},"log":{"leaf_index":"2844","tree_size":"3804","proof":["bdbebbd03f830d53f16633c28a87b177138d059e31174a43a09036ed06295e46","3febd9b324b03a95a47bf0393665efabbd00860e088602e5e49e32aa32490b4c","c8e2f9d616f7a6e54b855081a90dadd62eccdba4a56ec8cff2234603561580ae","6b9e253c7ab7601cbd84df9b6fd47b10248693b83c1b858434116f76aa3759a3","4e0c7928034e53655786e08aba842a44de57521cce73f55056d031c3b0e3ec59","a0ba22bdcd440355eb9a4f1ffc02d44cd5cf2f67a441ac64222032caf4bf0cb5","323cea358a3a8c2de393b15b814e7c2ae36cccb40b8dacbe21aab4e15da8014b","35943d50e127dd46c0e87af4e164fc8e3c68cc080e1e586a454baa6a53014e7a","56960156727d0f461a1b3857ab83f18526eaef848c820c927094afc1f989d56c","b0b232078d071c92816af6274529aef23a2ea1f41246694fec32d768cfa09dc8","325287f5a43e4f3ad4072ec4bd53d43c50c1393021a056122e9cb0fad83b868f","3c578dccc15502c5f3efe228cadc99fee76ab536ed01f66b14d316fdcc157429"],"checkpoint":"pubphys.com/log/v1\n3804\nAK6t4qgu96+M9wScTrIlsJ10d/zhKVEtYguyM3aeJvo=\n\n— pubphys.com/log/v1 JFPwIPP8EtoxgcsQg7V7CwIdL4UKPqJtpv+eB8sFNJjyQHIdyA1VabmBsPyLqq2bLxJPn57rA6fQi8y0QDDjRXHvlQg=\n","promise":"pubphys.com/log/v1 promise\nae9b0957a4deb955904afa37f8a47564d2cf1d92e0d318f7c869420da3020fd3\n2844\n2026-10-15T23:43:57Z\n2026-10-16T01:43:57Z\n\n— pubphys.com/log/v1 JFPwII+tRErbKsMJUoERLNkWg/uf2GEnUG2s7oyNLE0Bf7byB9OljasIfY5Aswp7HQZVtK7uAo38O9cY+qf8D3Djogw=\n"},"orcid_key_evidence":[],"attesting":null}