{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"874d6bf5039936ef27be9d1c8eb34c9d39071c990c52e2af27545d9aa6c105c1","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["18a481167193f5a6b3195ce0b7a7bf7224e59db1d998673fe38ffafdb1afb07d","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"69fa7a36cf8d24e5a269b326256d36ea0b3273c3ecc9d1d726ef8d96bef9806f","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"qi.gravity-quantum.superposed-source-gravity","kind":"well-posed","literature_status":"open","n":"2","parents":[],"plain":"Gravity has been measured from masses of about 90 milligrams, but never from an object that is itself in a superposition of two places. Doing so would show whether a quantum source pulls on a probe through its average position or through each branch separately.","posed_since":"","precise":"Prepare a source mass $M$ in a spatial superposition of separation $\\Delta x$ and measure a probe's response that distinguishes a field sourced by the expectation value $\\langle T_{00}\\rangle$ (Moller-Rosenfeld semiclassical gravity) from a branch-correlated field, at force scale $\\sim G M m_{\\mathrm{probe}} \\Delta x / d^3$. Required: source masses small enough to superpose ($M <\\sim 10^{-11}\\,\\mathrm{g}$) and probe force sensitivity at that scale.","problem_ref":"18a481167193f5a6b3195ce0b7a7bf7224e59db1d998673fe38ffafdb1afb07d","references":"","settled_by":"A probe measurement whose outcome statistics are correlated with the source branch (quantum) or follow the mean field (semiclassical).","status_note":"Page and Geilker (1981) excluded the simplest mean-field model using a classically randomized source; no experiment has used a source in a coherent spatial superposition.","title":"Measure the gravity of a mass that is in superposition","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"7e3804fe368853170fb46f49d0855dbc516a6f4a3e71d992555a43d42f2b4363","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"8cbab4b36472ae5f005739453ab9f11494abccd0932e528492de810b18292659","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"U3cBaAx5zRVgUo3-1niu5fWG5bmoFVADffGYHRd5_prhWWB-nDAag5wxDh2SEHYT8mCwoicaFc1ygTcrznDUDw"},"schema":"pubphys.envelope/1"},"record_hash":"7e3804fe368853170fb46f49d0855dbc516a6f4a3e71d992555a43d42f2b4363","leaf_index":3718}