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Title: Can soft gravitational charges carry the information of an evaporating black hole?
Plain: A black hole can carry tiny extra charges tied to zero-energy gravitons and photons, called soft hair. The question is whether this hair can store enough information to make evaporation information-preserving.
Precise: Supertranslation and superrotation (BMS) charges and the associated soft graviton modes at the horizon and null infinity were proposed as information carriers (Hawking, Perry, Strominger 2016). Count the independent soft-hair states accessible to a Schwarzschild black hole of mass M in the semiclassical regime and determine whether they can purify the Hawking radiation, i.e. carry of order $A c^{3}/(4 G \hbar)$ units of entropy correlated with the hard quanta. Answer yes or no with the entropy count.
Settled by: A computation of the entanglement between soft modes and hard Hawking quanta over the full evaporation, compared with the Bekenstein-Hawking entropy.
Kind: well-posed
Answer type: yes-no
References: (empty)
Literature status: partially-resolved
Status note: Several analyses argue soft modes decouple from hard Hawking quanta and cannot purify the radiation; no accepted count shows otherwise as of 2026.
Posed since: 2016