Black-Hole Microstate Hair Requires a Horizon Measurement

Abstract:Can a smooth horizon hide its microstates? At fixed classical and superselected data, the exterior distinguishability $D_{\max}$ of same-sector infalling states and the departure $\varepsilon$ from isometric infall obey $D_{\max}^{2}+(1-2\varepsilon)^{2}\leq 1$, 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.

8+8 Pages. Currently under review at Phys. Rev. Lett

arXiv:2604.28050 [quant-ph]

(or arXiv:2604.28050v2 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2604.28050 Focus to learn more arXiv-issued DOI via DataCite

arXivLabs is a framework that allows collaborators to develop and share new arXiv features directly on our website.

Both individuals and organizations that work with arXivLabs have embraced and accepted our values of openness, community, excellence, and user data privacy. arXiv is committed to these values and only works with partners that adhere to them.

Have an idea for a project that will add value for arXiv's community? Learn more about arXivLabs.