{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"8f8aadf05a96bcf74084f2a4bbe46f1f2ea44221e7a133d34fd71699b69836f9","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["c41e8ede167fd1bb3e4b02539fd0bcf9fe85e5c068b244cbfe3228721b5a7843","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"179c2cbaf90bd0523f0817b37fefd1bb4adfff1d9b1a3b290de7495b00401486","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":"2","parents":[],"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":"c41e8ede167fd1bb3e4b02539fd0bcf9fe85e5c068b244cbfe3228721b5a7843","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 > $6 \\times 10^{-8}$ 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":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"cb06327df8fbd5a7e618cd738785e9856131924dea6c55e8176f8bc376f0b75a","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"beb0c75c78b33f8c5d85ca462be6b191eb5e43c41dacfb33d16bd43d038e7bfa","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"0FAmdfRvOSXz8Cr9njbkiXo7-wDADYg1rkbaEoh6N8QlBojG_93bI2pBfFAs6RDpFnVvgqg9Wf4siviRNeGhCQ"},"schema":"pubphys.envelope/1"},"record_hash":"cb06327df8fbd5a7e618cd738785e9856131924dea6c55e8176f8bc376f0b75a","leaf_index":3312}