Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Density-matrix spectra for integrable models   The spectra which occur in numerical density-matrix renormalization group
(DMRG) calculations for quantum chains can be obtained analytically for
integrable models via corner transfer matrices. This is shown in detail for the
transverse Ising chain and the uniaxial XXZ Heisenberg model and explains in
particular their exponential character in these cases.

21
The categories of this paper are: adap-org
29
The categories of this paper are: funct-an
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The categories of this paper are: eess
37
The categories of this paper are: supr-con
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The categories of this paper are: solv-int
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The categories of this paper are: dg-ga
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
22
The categories of this paper are: chao-dyn
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The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: atom-ph
16
The categories of this paper are: stat
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph