{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"b831e0caed7a7d0d1818d0dbdc61c45d234dd4f7177863b12affb1675a663e92","created":"2026-10-03T07:17:53Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"ebfe81eda14952d5532f02b6c0d44275bff1c65316734561ccbfd34c6d093919","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":"1","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 $2e-5\\text{ to }1e-4\\,\\mathrm{cm}$: 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 $3e-4\\,\\mathrm{cm}$ where the thermal term is large.","problem_ref":null,"references":"","settled_by":"A measurement of the thermal Casimir force at gaps above 3e-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":"55304ca08284e7e9dcef4619089d0254a5b2c4ea521d0ef72f8036eb785a7e96"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"2066d8e015698977713132f34e3f38c7c92849f25d29876cb71211c39b469930","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"983de1b1f38034e6228582d6169e2c036e98bff57afada807a38af6801d500fd","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"-n6c1l8b_U56tixviaKjy31ojFey3Jgkks3lHbeiSuO24K1JtamC3eZIiRTPOm2sD1HzUpogB0XFm9o3mdE0BA"},"schema":"pubphys.envelope/1"},"record_hash":"2066d8e015698977713132f34e3f38c7c92849f25d29876cb71211c39b469930","leaf_index":379}