From: hal@finney.org
Date: Fri Jun 11 1999 - 15:37:32 MDT
Robin Hanson, <hanson@econ.berkeley.edu>, writes:
> Hal F. wrote:
> >Everyone seems to be ignoring Anders' post of a proof that wormholes can't
> >exist. The current state of play is that there ain't no such animals.
>
> The abstract of that paper said that it assumed positive energy density.
> Which just confirms that you need some negative energy to get wormholes.
Yes, this is true. However the very last paragraph of the paper claims
that the result is more general:
Finally, although the sketch of the topological censorship theorem
uses the null energy condition, one can show that it actually can be
rigorously proven for a weaker energy condition, the averaged null
energy condition. Physically this energy condition states that the
energy can be negative in small regions so long as it is positive when
averaged over the whole spacetime. This implies that the topological
censorship theorem can be applied not only to spacetimes with classical
matter but may also apply to spacetimes containing certain types of
quantum matter.
The paper is at http://xxx.lanl.gov/ps/gr-qc/9903061.
Hal
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