Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Superstrings on NSNS PP-Waves and Their CFT Duals   We investigate the correspondence between superstring theory on pp-wave
background with NSNS-flux and superconformal field theory on a symmetric
orbifold. This correspondence can be regarded as the ``Penrose limit'' of
AdS_3/CFT_2 correspondence. Superstring theory on the Penrose limit of AdS_3 x
S^3 (x M^4) (M^4 = T^4 or K3) with NSNS-flux can be described by a
generalization of Nappi-Witten model. We quantize this system in the covariant
gauge and obtain the spectrum of superstring theory. In the dual CFT point of
view, the Penrose limit means concentrating on the subsector of almost BPS
states with large R-charges. We show that stringy states can be embedded in the
single-particle Hilbert space of symmetric orbifold theory.

32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
21
The categories of this paper are: adap-org
34
The categories of this paper are: chem-ph
36
The categories of this paper are: cmp-lg
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The categories of this paper are: alg-geom
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The categories of this paper are: acc-phys
4
The categories of this paper are: cond-mat
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The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin