Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Black Holes: Classical Properties, Thermodynamics and Heuristic
  Quantization   I discuss the no hair principle, the recently found hairy solutions, generic
properties of nonvacuum spherical static black holes, and the new no scalar
hair theorems. I go into the generic phenomenon of superradiance, first uniform
linear motion superradiance, then Kerr black hole superradiance, and finally
general rotational superradiance and its possible applications in the
laboratory. I show that the horizon area of a nearly stationary black hole can
be regarded as an adiabatic invariant. This invariance suggests that quantum
horizon area is quantized in multiples of a basic unit. Consideration of the
quantum version of the Christodoulou reversible processes provides support for
this idea. Horizon area quantization dictates a definite discrete black hole
mass spectrum, so that Hawking's semiclassical spectrum is predicted to be
replaced by a spectrum of nearly uniformly spaced lines whose envelope is
roughly Planckian. Line natural broadening seems not enough to wash out the
lines. To check on the possibility of line splitting, I present a simple
algebra involving, among other operators, the black hole observables. Under
simple assumptions it also leads to the uniformly spaced area spectrum.

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The categories of this paper are: physics
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The categories of this paper are: q-alg
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The categories of this paper are: hep-th
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The categories of this paper are: quant-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: acc-phys
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The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
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The categories of this paper are: q-fin
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The categories of this paper are: hep-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: eess
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The categories of this paper are: atom-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: adap-org
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The categories of this paper are: dg-ga