There is a controversy about whether information is lost when it is dropped into a black hole, or somehow conserved as QM demands. The following arm-wave argument occurred to me:

Hawking made a semiclassical argument that near an event horizon, particles can be created in pairs from vacuum fluctuations and that one of such a pair might be drawn inside while the other is kicked away, forming Hawking radiation. This radiation has some energy, which comes from the black hole, thus enabling the black hole to eventually evaporate. This gets energy out of the BH but does not explain how any information might come out.

If however we consider that the particles created  might be created in an entangled state, and if they don't get decohered immediately, the particle emitted from the BH by the Hawking process will contain quantum information which would be altered by whatever happens inside the BH to its entangled partner. This might give a mechanism for information also to be extracted from inside the BH, so that talking about information not being forever lost by passing into a BH is reasonable.

I don't know how far this might go; this is an arm wave, not a proof. Recall that if you drop, say, a planet into a BH it has been suggested that energy is emitted in the process equivalent to a fraction of the mass energy lost (half?). If any of this were entangled, and did not get decohered, there might be larger information extractions possible. The Hawking mechanism is after all a trickle, slower the larger the BH gets.

Thought this might be worth sharing though.

Glenn C. Everhart
6 August 2019