{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"51d1d0735683296ecca4233af856f7e233a8ff6b688c772f60319a39e8b255db","created":"2026-10-03T07:18:05Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["05e4da055d00ca967f564973bc20b85087c81e5ba850b0661431ff996a221066","5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"b3941f9f6b7e2543703114a2643e7e99f1789080938425ac0f73567a91e1e927","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"grav.uv-completion.planck-lorentz-violation","kind":"well-posed","literature_status":"open","n":"1","parents":[{"note":"","parent_revision":"05e4da055d00ca967f564973bc20b85087c81e5ba850b0661431ff996a221066","relation":"special_case"}],"plain":"Some quantum gravity ideas make high-energy photons travel at slightly different speeds from low-energy ones. Gamma-ray bursts billions of light years away test this and already require any such linear effect to be weaker than Planck-scale estimates.","posed_since":"1998","precise":"Parametrize photon propagation as v(E) = c [1 - s ((n+1)/2) (E/E_QG,n)^n] with $s = +1$ (subluminal) or $-1$ (superluminal). Measure or bound E_QG,1 and E_QG,2 for both signs, and determine whether any candidate UV completion predicts a nonzero linear term consistent with these bounds. An answer is a detection of an energy-dependent arrival delay, or a demonstration that a given completion forbids linear Lorentz violation.","problem_ref":null,"references":"","settled_by":"Time-of-flight measurements of variable high-energy sources at cosmological distances with sensitivity beyond E_QG,1 = 10 E_P, together with predictions from specific completions.","status_note":"LHAASO observations of GRB 221009A give, for subluminal propagation, E_QG,1 > 10 E_P and E_QG,2 > 6 x 10^-8 E_P at 95 percent confidence (2024); superluminal effects are bounded separately by the absence of photon decay.","title":"Is the photon dispersion relation modified at linear order in $E/E_{\\mathrm{P}}$?","topic_ref":"c4c16a23d26fb15802115d6c08196860939989b3b47923782e43e698e37ba8b7"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"c41e8ede167fd1bb3e4b02539fd0bcf9fe85e5c068b244cbfe3228721b5a7843","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"9573dc804468d6652efe6ec4e83e4f47bec5c3c3ffd0858e115dfa360a3d8daf","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"76BbzRYEEauzlmEd2FiX6kKRUncaPt1Fa0edgwr4EDO1R6GDOnxFIVFxB-sUhzll8t-sXPqr85gnVpBzOMzHAg"},"schema":"pubphys.envelope/1"},"record_hash":"c41e8ede167fd1bb3e4b02539fd0bcf9fe85e5c068b244cbfe3228721b5a7843","leaf_index":1520}