{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"575f1ed54d028aa329fb13ce9af601b4dfd276bc210f1ad665ee24cacc8ece84","created":"2026-10-03T07:17:58Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"93aa1f9b85ed2b310b59d60a082920b4ba71f8295af1ef44a9e6205a17791285","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":"1","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 SiO2 (and a-Si, a-Al2O3), identify the atomic configurations that form tunneling two-level systems with energies below $\\sim 1e-4\\,\\mathrm{eV}$ ($\\sim 1\\,\\mathrm{K}$), 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":null,"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":"d5ba98a0b7fd03c8a459d017fd4e5e33d6f390cd71005b8a63b71f0973f4abf6"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"a66cd1c635e55e1c596798193e37a822aa65f54c099d89d28d965bebc120f930","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"08bdd822b37d6f9e9ceee790152b2eac1164306325ca93a0925cf95ecad8cb28","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"irs9Jqjbo3tk71UoPX3ng0_OG-QsalkkXMuBZrnke25Adz6UJnQyookPH7jnfOYFv-ioegwkoZHyVqKCatdkAg"},"schema":"pubphys.envelope/1"},"record_hash":"a66cd1c635e55e1c596798193e37a822aa65f54c099d89d28d965bebc120f930","leaf_index":906}