{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"059e475622f7651f1c36d6eefc9420b4f1ef2c18e236d5a70b6b7c1339aa9116","created":"2026-10-03T07:17:53Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"3f852b52d6fcf809f731fc5c3bb577385c04c4a0b81b900cc623c257ceef665c","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"amo.efimov-universality.unitary-bose-gas","kind":"phenomenon","literature_status":"partially-resolved","n":"1","parents":[],"plain":"A Bose gas tuned to infinitely strong pair interaction should behave in a universal way, but three-atom collisions destroy it quickly. The question is what state the gas reaches before it decays and what its energy is.","posed_since":"","precise":"Homogeneous single-species Bose gas quenched to $1/a = 0$ at density n. Determine the quasi-steady energy per particle in units of $E_{n} = \\hbar^{2} n^{2/3}/m$, the two-body contact $C_{2}$ and three-body contact $C_{3}$, and their log-periodic dependence on n through the three-body parameter. Answer: values with errors, or proof that no quasi-equilibrium exists on time scales shorter than three-body loss.","problem_ref":null,"references":"","settled_by":"Box-trap quench experiments measuring momentum distributions and contacts over several decades of density, compared with many-body theory including three-body physics.","status_note":"Quench experiments (JILA 2014; Cambridge, Eigen et al., Nature 2018) observed universal prethermal dynamics, and Ramsey interferometry measured $C_2$ and a first $C_3$ (Fletcher et al., Science 2017); the quasi-steady energy per particle and the log-periodic dependence of $C_3 \\text{ on } n$ remain undetermined.","title":"Equation of state and contacts of the unitary Bose gas","topic_ref":"339b6d63b4f6e3414be07628eacf49cfd6937fceb21d43c10a8b4202c093ede0"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"dad73b745cc27e596c163713fcb25d74fdf359caa2fba57cea6d592d606c1ffe","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"6957a311c8070f6a9377efe167461f758538a04d7e6b52c30123435546a2f4ee","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"Dmlbv1E8n-3bstsc3nqr_fkc7rdXnnhJ9mVqOrRiNLsXjricIAorh5ywP4-V64_El9sMlz87A3xiJMVZljS-Dg"},"schema":"pubphys.envelope/1"},"record_hash":"dad73b745cc27e596c163713fcb25d74fdf359caa2fba57cea6d592d606c1ffe","leaf_index":405}