{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"22d4d79bde787f6116f1d984b02545cb2c4fbeaa3559ad5e15738d93c90454a3","created":"2026-10-03T07:18:04Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"e5e4825a6bd6c0c6f11729350e78ebe66e08e4e2af993b6e5001071b3169a78e","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"grav.bh-information.islands-asymptotically-flat","kind":"well-posed","literature_status":"contested","n":"1","parents":[],"plain":"The island calculation assigns a region inside the black hole to the distant radiation. It is unclear whether this works when gravity acts everywhere with a massless graviton, as in our universe, instead of in model setups where the radiation escapes into a region without gravity.","posed_since":"2020","precise":"Consider a 4D asymptotically flat Schwarzschild black hole evaporating to null infinity, with dynamical massless gravity everywhere and no non-gravitating bath. Does the prescription S(R) = min ext_I [A(boundary of I) c^3/(4 G hbar) + S_bulk(R u I)] with a nontrivial island I give a well-defined, gauge-invariant entropy for a radiation region R that follows the Page curve? Answer yes with a construction of R and I compatible with the gravitational Gauss law, or no with a proof that islands require a massive graviton or a non-gravitating region.","problem_ref":null,"references":"","settled_by":"A gauge-invariant definition of the radiation algebra at null infinity together with a computation of its entropy, or a no-go theorem from the gravitational constraints.","status_note":"Arguments that islands require massive gravity (Geng and Karch 2020, extended 2025) and defenses of islands in massless gravity (2025) both stand as of 2026.","title":"Do entanglement islands exist for evaporating black holes in ordinary 4D gravity?","topic_ref":"f95e49a99ff690ea4913bd0d781eb50f5c958009660d629087f8ddfc66cb8a3b"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"af58776fedfd1a053558401942a2a60cf41c5a7444fc44efb5ad2259b1d40d88","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"77eab1e4e97ed74bfb95ded42ee833ce6b234cef9f005c69787bcc3b85d07be5","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"1rt_y_ibndwHgtbhZVXifZEqVlJ8juLCyGKtpSp_CGdyZZZUGendtKYvAZdcceYzLoVUi4z1q0m5CGvAC3yXCQ"},"schema":"pubphys.envelope/1"},"record_hash":"af58776fedfd1a053558401942a2a60cf41c5a7444fc44efb5ad2259b1d40d88","leaf_index":1465}