[extropy-chat] info on info

scerir scerir at libero.it
Fri Jul 2 21:40:18 UTC 2004

At the GR17, the 17th International Conference 
on General Relativity and Gravitation, that takes 
place from 18th to 23rd July 2004 in Dublin, Ireland,
It seems that Stephen Hawking (Cambridge) gives a lecture
on "The information paradox for black holes", following
this abstract:
"The Euclidean path integral over all topologically trivial 
metrics can be done by time slicing and so is unitary when 
analytically continued to the Lorentzian. On the other hand, 
the path integral over all topologically non-trivial metrics 
is asymptotically independent of the initial state. Thus
the total path integral is unitary and information is not lost 
in the formation and evaporation of black holes. The way the 
information gets out seems to be that a true event horizon 
never forms, just an apparent horizon".

[The above - perhaps - means that information does not vanish,
in the BH dynamics. Information cannot be deleted in QM also,
just erased, at most. So, good news.] 

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