{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"b67983f1bd4412e2621cef0a49db7a9620e71de9d1f3d8c3cdf512999cc635d0","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["a66cd1c635e55e1c596798193e37a822aa65f54c099d89d28d965bebc120f930","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"7a85dbb8fbea01df23884b294dcd0b85c70cf4625aace9cb277fb21af1d7e413","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"identification","assisted_by":[],"external_id":"cm.amorphous-low-temperature.tls-identity","kind":"well-posed","literature_status":"open","n":"2","parents":[],"plain":"The tunneling model assumes small groups of atoms that flip between two nearly equal positions. Which atoms move, and how many, has never been identified in any glass.","posed_since":"","precise":"For amorphous $\\mathrm{SiO_2}$ (and a-Si, a-Al2O3), identify the atomic configurations that form tunneling two-level systems with energies below $\\sim 10^{-4}\\,\\mathrm{eV}$ ($\\sim 1\\,\\mathrm{K}$), and reproduce their measured density of states $P$, deformation potential $\\gamma \\sim 0.5-1\\,\\mathrm{eV}$, electric dipole moments and isotope dependence.","problem_ref":"a66cd1c635e55e1c596798193e37a822aa65f54c099d89d28d965bebc120f930","references":"","settled_by":"Atomistic simulation of a realistically quenched glass that finds tunneling double wells with the measured $P$, $\\gamma$ and dipole moments, confirmed by an isotope-substitution or strain-spectroscopy experiment.","status_note":"","title":"What atoms tunnel in the two-level systems of amorphous silica?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"be90e5795e37fc99a27d1cc7c9603cb111281080e64e7b7edf4af089e57de9f5","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"5882d5a0146a315687aa7fcb0b19c46aac00737054e78e1b5be8516dda3bca54","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"KbNbJNbzu1B24frhSnH_ALfpkWvHApWeJvYSuVgfX4IYV6bL2C4jEB3yaD3O82uCGFZDaueC3X3_4rz-5Ms3Aw"},"schema":"pubphys.envelope/1"},"record_hash":"be90e5795e37fc99a27d1cc7c9603cb111281080e64e7b7edf4af089e57de9f5","leaf_index":2696}