Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Strings in a 2-d Extremal Black Hole   String theory on 2-d charged black holes corresponding to (SL(2)xU(1)_L)/U(1)
exact asymmetric quotient CFTs are investigated. These backgrounds can be
embedded, in particular, in a two dimensional heterotic string. In the extremal
case, the quotient CFT description captures the near horizon physics, and is
equivalent to strings in AdS_2 with a gauge field. Such string vacua possess an
infinite space-time Virasoro symmetry, and hence enhancement of global
space-time Lie symmetries to affine symmetries, in agreement with the
conjectured AdS_2/CFT_1 correspondence. We argue that the entropy of these 2-d
black holes in string theory is compatible with semi-classical results, and
show that in perturbative computations part of an incoming flux is absorbed by
the black hole. Moreover, on the way we find evidence that the 2-d heterotic
string is closely related to the N=(2,1) string, and conjecture that they are
dual.

1
The categories of this paper are: cs
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn