Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nonequilibrium dynamics in the O(N) model to next-to-next-to-leading
  order in the 1/N expansion   Nonequilibrium dynamics in quantum field theory has been studied extensively
using truncations of the 2PI effective action. Both 1/N and loop expansions
beyond leading order show remarkable improvement when compared to mean-field
approximations. However, in truncations used so far, only the leading-order
parts of the self energy responsible for memory loss, damping and equilibration
are included, which makes it difficult to discuss convergence systematically.
For that reason we derive the real and causal evolution equations for an O(N)
model to next-to-next-to-leading order in the 2PI-1/N expansion. Due to the
appearance of internal vertices the resulting equations appear intractable for
a full-fledged 3+1 dimensional field theory. Instead, we solve the closely
related three-loop approximation in the auxiliary-field formalism numerically
in 0+1 dimensions (quantum mechanics) and compare to previous approximations
and the exact numerical solution of the Schroedinger equation.

32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
16
The categories of this paper are: stat
19
The categories of this paper are: eess
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas
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The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin