{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"bb39268817b1928b35fdd5fbefb702b43d2e08ae906cc9771ca09f5810aab770","created":"2026-10-03T07:17:53Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"150b45d690e732ba9b2781ca5d512e3d68f94fae4ae559dd3653708812d82695","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"amo.casimir-dispersion-forces.vacuum-repulsion","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"Casimir forces are almost always attractive, and they have been made repulsive only with a liquid between the objects. Predicted repulsion across empty space, using magnetic, chiral or topological materials, has never been seen.","posed_since":"1974","precise":"Repulsive Casimir-Lifshitz force between two solid bodies across vacuum. Mirror-symmetric arrangements of identical bodies always attract (Kenneth-Klich theorem, 2006); repulsion is predicted for dielectric-magnetic pairs (Boyer, 1974), topological insulators with axion electrodynamics, and chiral metamaterials, but material dispersion usually restores attraction. An answer is a measured repulsive force with sign and magnitude matching Lifshitz theory for the measured permittivities and permeabilities, or a theorem that excludes repulsion for all passive materials at accessible gaps.","problem_ref":null,"references":"","settled_by":"A sphere-plate or plate-plate force measurement across vacuum showing a repulsive force at a given gap, reproduced by Lifshitz theory with independently measured material response.","status_note":"Repulsion has been measured only across fluids (Munday, Capasso and Parsegian, Nature 2009).","title":"Casimir repulsion between solid bodies separated by vacuum","topic_ref":"55304ca08284e7e9dcef4619089d0254a5b2c4ea521d0ef72f8036eb785a7e96"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"30fa20dffec836a2567f2aa27c595f8b7279bc6cc299b2060977e64b885e854a","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"180625c449d53a414f61d144cf8cb2437cc8247d36c3cd3e921633e0617cc431","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"IScOPAwxG4E2hQ0o9CMxWs79P7sD51fVbFWuNh8LF3ZvStOCse6xecuUMTFcCX9F57F0dBy0Ck8QgNzQcOW2Cg"},"schema":"pubphys.envelope/1"},"record_hash":"30fa20dffec836a2567f2aa27c595f8b7279bc6cc299b2060977e64b885e854a","leaf_index":382}