2026/04/30 by Sudhanva Joshi, Sunil Kumar Mishra
Physics and Astronomy · #quant-ph #gr-qc #hep-th
8+8 Pages. Currently under review at Phys. Rev. Lett
arxiv created 2026/08/06 · arxiv updated 2026/08/07
Can a smooth horizon hide its microstates? At fixed classical and superselected data, the exterior distinguishability Dmax of same-sector infalling states and the departure ε from isometric infall obey Dmax2+(1-2ε)2≤ 1, and every point is realized. Below maximal disruption, the boundary is reached only by which-state measurements: the distinguished pair crosses undisturbed while the exterior records which one fell in. The least a horizon can do to have microstate hair is measure what falls in. Classically hairy black holes are labeled backgrounds, not microstate hair.