{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"e41d8c0063dc65e31e3754a062a9ed034ef138b4b245f0c47d7d69f79c4da5e0","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["2066d8e015698977713132f34e3f38c7c92849f25d29876cb71211c39b469930","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"30fd14125b6ff63843cbfc9e6ff263e9641b572354fe6fbf3ae72e57de431990","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"amo.casimir-dispersion-forces.drude-plasma-puzzle","kind":"phenomenon","literature_status":"contested","n":"2","parents":[],"plain":"The Casimir force between metals at room temperature depends on how electrons in the metal lose energy. Calculations using the standard description of a real, resistive metal disagree with most precision measurements, which instead match a description that ignores resistance.","posed_since":"2000","precise":"Lifshitz theory for Au or Ni sphere-plate geometries at $T = 300\\,\\mathrm{K}$ and separations $2 \\times 10^{-5}\\text{ to }10^{-4}\\,\\mathrm{cm}$: the Drude permittivity $\\epsilon(\\omega) = 1 - \\omega_p^2/(\\omega(\\omega + i \\gamma))$ removes the zero-frequency transverse-electric Matsubara term, while the plasma model ($\\gamma = 0$) keeps it. Micromechanical, dynamic AFM and isoelectronic differential measurements agree with the plasma model and exclude Drude, whereas a torsion-pendulum measurement at larger gaps (Sushkov et al., 2011) favored Drude after subtracting electrostatic patch forces. An answer is a physical mechanism (spatial dispersion, surface states, low-frequency response) that reproduces the data while staying consistent with measured optical and dc conductivity, confirmed at separations above $3 \\times 10^{-4}\\,\\mathrm{cm}$ where the thermal term is large.","problem_ref":"2066d8e015698977713132f34e3f38c7c92849f25d29876cb71211c39b469930","references":"","settled_by":"A measurement of the thermal Casimir force at gaps above $3 \\times 10^{-4}$ cm with patch potentials characterized independently, plus a dielectric model that fits it and the metal's measured transport and optics.","status_note":"Nonlocal and surface-response resolutions were proposed in 2025 (J.-S. Wang, Physical Review B 111, 245404) and magnetic-metal data were reanalyzed in 2026 (Klimchitskaya, Korikov and Mostepanenko, Physics 8, 33, https://doi.org/10.3390/physics8020033); none is accepted.","title":"Why thermal Casimir data favor the dissipationless plasma model","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"000f7550c92c4b08ac2cc3d1581ae1282df662ae76ac47e410c8373dcb9c7b8a","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"8250003e68c7dd0531dc5dc038f12b5866e82ef6a6370ad052cfcf5a5708f9da","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"YknYEdQEX7-bSiTFrnIZY-TwoBnZ0MlHJAu5hIP0nPosQOdH-Whwskf7HI603DG40q58VqLDb3-FenjC7uggCQ"},"schema":"pubphys.envelope/1"},"record_hash":"000f7550c92c4b08ac2cc3d1581ae1282df662ae76ac47e410c8373dcb9c7b8a","leaf_index":2200}