Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pion propagation in real time field theory at finite temperature   We describe how the thermal counterpart of a vacuum two-point function may be
obtained in the real time formalism in a simple way by using directly the
$2\times 2$ matrices that different elements acquire in this formalism. Using
this procedure we calculate the analytic (single component) thermal amplitude
for the pion pole term in the ensemble average of two axial-vector currents to
two loops in chiral perturbation theory. The general expressions obtained for
the effective mass and decay constants of the pion are evaluated in the chiral
and the nonrelativistic limits. We also investigate the effect of massive
states on these effective parameters.

28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
23
The categories of this paper are: solv-int
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ