Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Infra-red divergences in the large-N expansion   We investigate a vectorial O(N) model with a generic nearest-neighbor
interaction W(\bsigma_i\cdot \bsigma_j) (depending on {\cal N} tunable
parameters), a Yukawa (and Gross Neveu) model with N_f fermions at finite
temperature and the vectorial \phi^6 model, in the large N (N_f) limit. All
this models exhibit a Mean Field critical point for N=\infinity. When 1/N
fluctuations are included, infra red divergences appear near the critical
point. In the framework of a generalized 1/N expansion we show that these
divergences are related to a universal crossover mechanism between the Mean
Field universality class (N=\infinity) and the nonclassical one for
N<\infinity. For the generic nearest-neighbor interaction multicritical points
are also investigated.

10
The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
22
The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math