{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"9d5cd71b1516176142547fc41ea871a031b2b5fccf1ce1350d8b573c685c9006","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["31a3a46024546948749390b73fc545a6b30dc5d0bfdeb81438cb4ac0924ce169","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"1b588b992d7c7f72bad4955aa7e01dc4858159c52d64cf7f2bfa021a5a573ac2","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"cm.spin-ice.dy2ti2o7-ground-state","kind":"well-posed","literature_status":"contested","n":"2","parents":[],"plain":"Ice-rule states are so numerous that spin ice keeps a leftover entropy at low temperature, as water ice does. Long-range dipolar forces predict an ordered state below about 0.2 K, but experiments struggle to reach equilibrium there.","posed_since":"2001","precise":"In $\\mathrm{Dy_2Ti_2O_7}$, determine whether thermal equilibrium below 0.5 K approaches the ordered state predicted by the dipolar spin-ice model (transition near 0.18 K) with loss of the Pauling entropy $(R/2)\\ln(3/2)$ per mole Dy, or retains a disordered ice manifold. An answer is the equilibrium entropy and any ordering wavevector as $T \\to 0$.","problem_ref":"31a3a46024546948749390b73fc545a6b30dc5d0bfdeb81438cb4ac0924ce169","references":"","settled_by":"Equilibrium heat capacity and neutron scattering below 0.3 K after controlled long annealing, compared with Monte Carlo of the fitted dipolar model.","status_note":"Pomaranski et al. (Nature Physics 2013) found the residual entropy is lost after long equilibration without detecting the predicted order.","title":"Does classical spin ice $\\mathrm{Dy_2Ti_2O_7}$ order or keep its Pauling entropy?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"6bae9a7429994b49cedcf21548bf1470acd35b7a2a0e07d81c07754b4f4307f9","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"6d8db4dba47ab030a752ad042d6dfe90b151917faddd908eeb20b2255f643fdf","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"mTFOwNSOB2-sigHw2xBZGQEWtvgwmBhfFDtEZ48vMKLiQBCVJVij6XgxXMniijTXafjCc_Q7HhnZ-6KMvDgCDg"},"schema":"pubphys.envelope/1"},"record_hash":"6bae9a7429994b49cedcf21548bf1470acd35b7a2a0e07d81c07754b4f4307f9","leaf_index":3042}