- #1
jimgraber
Gold Member
- 247
- 18
In the context of the recent Fuzz or Fire workshop,
http://online.kitp.ucsb.edu/online/fuzzorfire_m13/
I would like to make a short argument that event horizons are irredeemably in conflict with unitarity:
An argument frequently mentioned in the Fuzz or Fire workshop is that by the principle of equivalence you should not be able to tell if you are falling in through the event horizon of a large black hole. I would extend this to say that similarly, you should not even be able to detect if you are emerging out through the event horizon of a large black hole. Since this is manifestly false, by reductio, you should conclude that event horizons are irreducibly problematic for unitarity. As singularities are also agreed (almost universally) to destroy unitarity, if you want quantum gravity to be compatible with unitarity, you require a black hole like object with neither a singularity nor an event horizon.
(I have been proposing this necessity for many years)
Singularities have been unpopular forever. It is encouraging to find that horizons are also now being challenged by serious researchers.
Jim Graber
http://online.kitp.ucsb.edu/online/fuzzorfire_m13/
I would like to make a short argument that event horizons are irredeemably in conflict with unitarity:
An argument frequently mentioned in the Fuzz or Fire workshop is that by the principle of equivalence you should not be able to tell if you are falling in through the event horizon of a large black hole. I would extend this to say that similarly, you should not even be able to detect if you are emerging out through the event horizon of a large black hole. Since this is manifestly false, by reductio, you should conclude that event horizons are irreducibly problematic for unitarity. As singularities are also agreed (almost universally) to destroy unitarity, if you want quantum gravity to be compatible with unitarity, you require a black hole like object with neither a singularity nor an event horizon.
(I have been proposing this necessity for many years)
Singularities have been unpopular forever. It is encouraging to find that horizons are also now being challenged by serious researchers.
Jim Graber