{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"658a0aa15ef9e9ec3c2fc9e534e65d0a61c308e43c60f2d4832d8a9c45669c31","created":"2026-10-03T07:18:00Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"dc72ef0dc474e8f12cdb004571f854c7837185c810a4e27f3ca03fa83c41cc0f","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"classification","assisted_by":[],"external_id":"cm.nonthermal-fixed-points.universality-classification","kind":"well-posed","literature_status":"partially-resolved","n":"1","parents":[],"plain":"Experiments in one-, two- and three-dimensional atomic gases find self-similar stretching of correlations, with exponents that differ between systems. Which distinct universal classes exist, and what selects the class, is not known.","posed_since":"","precise":"In an isolated Bose gas after a quench, the momentum occupation obeys $f(k,t)=t^{\\alpha} f_s(t^{\\beta} k)$ in a scaling window. Determine the set of fixed points ($\\alpha, \\beta$ and the scaling function $f_s$) and the properties that select them: dimension d, number of field components and symmetry (scalar or spinor), conservation laws, and topological defects. Experimental inputs: 1D (Erne et al., Nature 563, 225, 2018), spinor (Prufer et al., Nature 563, 217, 2018), 3D homogeneous (Glidden et al., Nature Physics 17, 457, 2021). Answer: a classification with computed exponents matching the measured ones.","problem_ref":null,"references":"","settled_by":"A renormalization-group or kinetic theory predicting $\\alpha$ and $\\beta$ for each experimental system, confirmed by measurements in which $d$ or the symmetry is varied.","status_note":"Wave-kinetic and defect-dominated fixed points are identified in theory; not every measured exponent set is matched to a predicted class (moderate confidence).","title":"Classification of nonthermal fixed points and their scaling exponents","topic_ref":"35186f9e2deef9f8d2782c17ad7162983dedfc7f904b938244b253e7e8dca1d3"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"53307f8d4e492fd5c57cb409f68e6e93ca917a75d66291e45a240f921213cd6c","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"fe28dbdef22a21f48c3d8398d51eab69a373f4bfa43896e0ec259648f450bbc4","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"mJmjJVQS121LT2bkJbqto83pVvMiZj12I-QO0jxmdpR4nQ4KsFqJJaqG01eQaogG9qWgosYv2mWdVxurUexmDw"},"schema":"pubphys.envelope/1"},"record_hash":"53307f8d4e492fd5c57cb409f68e6e93ca917a75d66291e45a240f921213cd6c","leaf_index":1117}