Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Variational calculations with improved energy functionals in gauge
  theories   For a SU(N) Yang-Mills theory, we present variational calculations using
gaussian wave functionals combined with an approximate projection on gauge
invariant states. The projection amounts to correcting the energy of the
gaussian states by substracting the spurious energy associated with gauge
rotations. Based on this improved energy functional, we perform variational
calculations of the interaction energy in the presence of external electric and
magnetic fields. We verify that the ultraviolet behaviour of our approximation
scheme is consistent, as it should, with that expected from perturbation
theory. In particular, we recover in this variational framework the standard
one-loop beta function, with a transparent interpretation of the screening and
anti-screening contributions.

14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
36
The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
13
The categories of this paper are: quant-ph