{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"cc205df9d903cbb3eab60b68fa5a7eb6bf6285323a9c16016ee2006cdcfe22ab","created":"2026-10-03T07:18:04Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011","d688812b1bee9ce3b27f7a45bbba9ae0b1eef393362910a295fe39a39ed51955"],"salt":"d3abcfe829b8449927e38bd48ea3f9524f6f4a280280197df4ea616406f13a90","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"grav.bh-microstates.string-black-hole-transition","kind":"well-posed","literature_status":"partially-resolved","n":"1","parents":[{"note":"","parent_revision":"d688812b1bee9ce3b27f7a45bbba9ae0b1eef393362910a295fe39a39ed51955","relation":"special_case"}],"plain":"If a black hole shrinks until its horizon is as small as a fundamental string, it should turn into a single highly excited string, and the two entropy formulas roughly agree there. Whether this crossover is smooth, with an exact match of states, is not established.","posed_since":"1993","precise":"In weakly coupled string theory in 4D asymptotically flat space, follow a Schwarzschild black hole as the string coupling $g_s$ decreases at fixed entropy until $r_s \\sim l_s$. Determine whether the black hole connects continuously to a self-gravitating highly excited string state (Horowitz-Polchinski solution), with the entropy matched including $O(1)$ factors. An answer is a controlled computation of the free energy across $r_s \\sim l_s$, or a proof of a phase transition.","problem_ref":null,"references":"","settled_by":"A computation of the thermodynamics across the correspondence point in $D = 4$ with controlled corrections in $g_s$ and $\\ell_s/r_s$.","status_note":"Chen, Maldacena and Witten (2021) mapped where self-gravitating string solutions exist and how they connect to black holes; exact matching across the transition is open as of 2026.","title":"Is the string to black hole transition smooth for Schwarzschild black holes?","topic_ref":"1035ad33d8a9ccd80488cee2f65c345c1f7222bd089aa039ccbbf4731a2f59f2"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"0906ff7a9e10a83a19cd04c8d62ed20310a213a6f1fa5274d7f9ee359073314c","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"ea23ffac03645f498cbb11afe14f22c08bd180e46dbe6ce980ce5fab7e8ad4a4","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"znQ2avV9Awknc9KxPhFvBmqIPQTnV2LS1emIOlK-o4yvE2qI03FgIUzoAdkk2zydSGRwMaQoP3bh_ye3ju1qAw"},"schema":"pubphys.envelope/1"},"record_hash":"0906ff7a9e10a83a19cd04c8d62ed20310a213a6f1fa5274d7f9ee359073314c","leaf_index":1476}