Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Adaptive cluster approximation for reduced density-matrix functional
  theory   A method, called the adaptive cluster approximation (ACA), for
single-impurity Anderson models is proposed. It is based on reduced
density-matrix functional theory, where the one-particle reduced density matrix
is used as the basic variable. The adaptive cluster approximation introduces a
unitary transformation of the bath states such that the effect of the bath is
concentrated to a small cluster around the impurity. For this small effective
system one can then either calculate the reduced density-matrix functional
numerically exact from Levy's constrained-search formalism or approximate it by
an implicit approximation of the reduced density-matrix functional. The method
is evaluated for single-impurity Anderson models with finite baths. The method
converges rapidly to the exact result with the size of the effective bath.

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The categories of this paper are: funct-an
3
The categories of this paper are: physics
10
The categories of this paper are: q-bio
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
6
The categories of this paper are: astro-ph
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
27
The categories of this paper are: comp-gas
28
The categories of this paper are: alg-geom
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The categories of this paper are: supr-con
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The categories of this paper are: econ
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph