{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"ef9dc2ff8d83463b7d00b942a3b625d63d9cad8e0a11586cf701db1f2033d1a7","created":"2026-10-03T07:17:59Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"3c586a99f6401895d0607e1f3c7a8e02c894ff5338fd60ef164109b885f386dc","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"classification","assisted_by":[],"external_id":"cm.helium3-quantum-solids.2d-3he-spin-liquid","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"A layer of helium-3 atoms adsorbed on graphite forms a triangular solid in which nuclear spins interact through atoms exchanging places in rings. Down to the lowest temperatures reached, these spins show no order, suggesting a quantum spin liquid.","posed_since":"","precise":"At the $4/7$ commensurate density of the 2D solid 3He layer on preplated graphite, multiple-spin ring exchange on a triangular lattice produces no magnetic order: magnetization measured by direct nuclear demagnetization rises smoothly down to about $1e-5\\,\\mathrm{K}$, which bounds any spin gap below about $1e-5\\,\\mathrm{K}$ (Masutomi et al. 2004). Determine the ground state of the triangular ring-exchange model at the measured $J2, J4, J5, J6$ ratios and test experimentally whether the state is a gapless spin liquid, gapped, or ordered. An answer is a classification supported by both computation and data below $1e-5\\,\\mathrm{K}$.","problem_ref":null,"references":"","settled_by":"Heat capacity and susceptibility below 1e-5 K together with a controlled numerical solution of the ring-exchange model at the measured couplings.","status_note":"","title":"Is second-layer 3He on graphite a gapless spin liquid","topic_ref":"16fbf45f3606bcc2e9eb1edee75f8360d28657af82c155c213da344ce6ff8cd5"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"b1b88f2951011c1f6ea359f504e641fbd33fae0b261707a1d1a80014b91a74f5","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"2a6c2496716d818ef5e8d9e829f2eb9c3cae86f4b2383695e2a7f0c9cc61e814","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"Uxc1cyMICEJEhZPYmy3RJymJkwc5Mud5IAMShBq5OJeb_8GqC1bHlkVmCULl1lrWIzXZfu1fkk-Pu1PWqwfcAA"},"schema":"pubphys.envelope/1"},"record_hash":"b1b88f2951011c1f6ea359f504e641fbd33fae0b261707a1d1a80014b91a74f5","leaf_index":1018}