Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ferromagnetism in one-dimensional metals: breakdown of the Hartree-Fock
  approximation and possible first order phase transition   We calculate the Gibbs potential Gamma (M) of a one-dimensional metal at
constant magnetization M to second order in the screened electron-electron
interaction U. At zero temperature we find that Gamma (M) contains non-analytic
corrections proportional to M^2 \ln | M| and | M |^3, implying that a possible
paramagnetic-ferromagnetic quantum phase transition in one-dimensional metals
must be first order.

8
The categories of this paper are: hep-ex
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The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
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The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
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The categories of this paper are: eess