Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum Black Holes: the Event Horizon as a Fuzzy Sphere   Modeling the event horizon of a black hole by a fuzzy sphere it is shown that
in the classical limit, for large astrophysical black-holes, the event horizon
looks locally like a non-commutative plane with non-commutative parameter
dictated by the Planck length. Some suggestions in the literature concerning
black hole mass spectra are used to derive a formula for the mass spectrum of
quantum black holes in terms of four integers which define the area, angular
momentum, electric and magnetic charge of the black hole. We also suggest how
the classical bounds on extremal black holes might be modified in the quantum
theory.

8
The categories of this paper are: hep-ex
21
The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
3
The categories of this paper are: physics
0
The categories of this paper are: hep-ph
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con