Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum States of Black Holes   I review the recent progress in providing a statistical foundation for black
hole thermodynamics. In the context of string theory, one can now identify and
count quantum states associated with black holes. One can also compute the
analog of Hawking radiation (in a certain low energy regime) in a manifestly
unitary way. Both extremal and nonextremal black holes are considered,
including the Schwarzschild solution. Some implications of conjectured
non-perturbative string ``duality transformations'' for the description of
black hole states are also discussed.

4
The categories of this paper are: cond-mat
18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
37
The categories of this paper are: supr-con
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
21
The categories of this paper are: adap-org