Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Zero temperature black holes in semiclassical gravity   The semiclassical Einstein equations are solved to first order in $\epsilon =
\hbar/M^2$ for the case of an extreme or nearly extreme Reissner-Nordstr\"{o}m
black hole perturbed by the vacuum stress-energy of quantized free fields. It
is shown that, for realistic fields of spin 0, 1/2, or 1, any zero temperature
black hole solution to the equations must have an event horizon at $r_h < |Q|$,
with $Q$ the charge of the black hole. It is further shown that no black hole
solutions with $r_h < |Q|$ can be obtained by solving the semiclassical
Einstein equations perturbatively.

31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
24
The categories of this paper are: dg-ga
28
The categories of this paper are: alg-geom
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ