Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: General formula for the four-quark condensate and vacuum factorization
  assumption   By differentiating the dressed quark propagator with respect to a variable
background field, the linear response of the dressed quark propagator in the
presence of the background field can be obtained. From this general method,
using the vector background field as an illustration, we derive a general
formula for the four-quark condensate $<{\tilde 0}|:{\bar q}(0)\gamma_\mu
q(0){\bar q}(0)\gamma_\mu q(0):|{\tilde 0}>$. This formula contains the
corresponding fully dressed vector vertex and it is shown that factorization
for $<{\tilde 0}|:{\bar q}(0)\gamma_\mu q(0){\bar q}(0)\gamma_\mu q(0):|
{\tilde 0}>$ holds only when the dressed vertex is taken to be the bare one.
This property also holds for all other type of four-quark condensate.

37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
4
The categories of this paper are: cond-mat
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph