Re: If we had a Renormalizable Theory of Gravitation, What Broad Features Would we Expect it to Have?

"sr" <strangerep@xxxxxxxxxxxx> wrote in message
news:1158629962.848946.164680@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

<snip>

For gravitation, there were attempts ages ago to
quantize it by the canonical formalism. It was
found that such a quantized theory of a spin-2
field is non-renormalizable.

Since renormalizability of an interacting theory
really just indicates whether we can extract
physical sense out of a perturbation around the
free theory, non-renormalizability just means
that we can't solve the interacting theory by
such means. OTOH, we know rather little about
solving QFTs by other means.

Even though any canonically quantized gravitational perturbation theory
is non-renormalizable,
do they have anything sensible to say? Or is it complete nonsense at the
one-loop level?

What prompts my question are Hawkings arguments for Black-Hole radiation,
which
I only understand at a layman's pictorial level. Even though gravity may
may not be canonically renormalizable, can it still be quantized and
regulated at some energy level
much higher than needed for Hawking's arguments?

If so, can such a quantized, regulated (non-renormalizable) theory be
coupled with, say, the standard model or
some renormalizable particle theory, and generate (at some low order of
perturbation theory about the
classical Black Hole solution) the Black Hole evaporation effect? My
layman's picture of the evaporation effect
resembles Feynman diagrams, which is another reason for the question.

alan



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