Didn't I Tell You

...that We don't need no Stinkin Black Holes?

Tanmay Vachaspati, Dejan Stojkovic, Lawrence M. Krauss have a new paper on the ArXiv, Observation of Incipient Black Holes and the Information Loss Problem (gr-qc/0609024) that tends to support my favorite crackpot theory.

We study the (quantum) formation of black holes by spherical domain wall collapse as seen by an asymptotic observer. Using the Wheeler-de Witt equation to describe the collapsing spherical domain wall, we show that the black hole takes an infinite time to form for the asymptotic observer in the quantum theory, just as in the classical treatment. We argue that such observers will therefore see a compact object but never see effects associated with the formation of an event horizon...

Even more interestingly, they find that the compact object radiates, but that it's radiation is only approximately thermal, and so not quite like Hawking's - though it goes to thermal in Hawking's limit t->infinity.

There are some caveats, but they also have some suggestions for tests. The most interesting, to me, was the test in the case of sonic analogues of black holes - or so-called dumbholes.

No theoretical idea is complete without the possibility
of experimental verification and so it is important to ask
if the picture we have developed in this paper can also
be tested experimentally. We have already mentioned
the relevance of our conclusions to black hole produc-
tion in particle accelerators provided low scale gravity is
correct. However, there is an even more accessible ex-
perimental system where these theoretical ideas can be
put to the test. These are condensed matter systems in
which sonic black holes (dumbholes) may exist. It is well-
appreciated that it is very hard to realize a dumbhole in
the laboratory for various experimental reasons. Yet the
crucial aspect of our work in this paper is that there is
no need to produce a dumbhole in order to see acous-
tic “pre-Hawking” radiation. The process of collapse to-
ward a dumbhole will give off radiation. This is also the
conclusion of Ref. [9] though the details of the analy-
sis and conclusions are different – for example, we find
non-thermal emission whereas Barcelo et al claim ther-
mal emission with a modified temperature that is lower
than the Hawking temperature. In any case, it should be
much easier to do experiments in the laboratory that do
not go all the way to forming a dumbhole, and this could
be an ideal arena to test pre-Hawking radiation.