{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"155cf63533bddac6788a4d5b4f1130bb54001167a3137c8d351c435da0200790","created":"2026-10-03T07:17:58Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"98e2ce3430b7fa952f5d9e9580b3f4f9cb42c575456cf6c420eae361439150f5","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"cm.amorphous-low-temperature.boson-peak-origin","kind":"phenomenon","literature_status":"contested","n":"1","parents":[],"plain":"Glasses have more low-frequency vibrations than a crystal would, which shows up as a bump in the vibration spectrum near one terahertz called the boson peak. Which structural feature creates this excess is disputed.","posed_since":"","precise":"In amorphous solids the ratio $g(\\omega)/\\omega^{2}$ (vibrational density of states over the Debye law) peaks at $\\omega_{\\mathrm{BP}}/2\\pi \\sim 0.5-2\\,\\mathrm{THz}$ (about $2-8\\,\\mathrm{meV}$), near the transverse Ioffe-Regel frequency, and correlates with the plateau of thermal conductivity near $10\\,\\mathrm{K}$. Decide between heterogeneous elasticity (random elastic constants), quasi-localized soft modes with $g \\sim \\omega^{4}$, a smeared van Hove singularity of transverse acoustic branches, and marginal-stability explanations, by a quantitative prediction of $\\omega_{\\mathrm{BP}}$ and the peak height across glasses.","problem_ref":null,"references":"","settled_by":"A theory predicting $\\omega_{BP}$ and peak height from measured elastic constants and structure for several glasses, verified by inelastic neutron or x-ray scattering under pressure or densification.","status_note":"","title":"Origin of the boson peak in glasses","topic_ref":"d5ba98a0b7fd03c8a459d017fd4e5e33d6f390cd71005b8a63b71f0973f4abf6"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"0a6165fc9222b782969734fde05606af1ff514fd73b69d8e345a1e99b208eaab","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"3f645c57a4ed4b23217bda6c1c7f3c324f3751d432f91d8baa784334268a46b1","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"sbpmsnw0VY5ynpC6sPwuJLrJNSBpbazx7ye9NXLNAH23C8RJ-tBngM5TrLOYaSYon0e1OMheq3JLYCMEqIiEDA"},"schema":"pubphys.envelope/1"},"record_hash":"0a6165fc9222b782969734fde05606af1ff514fd73b69d8e345a1e99b208eaab","leaf_index":904}