Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On some aspects of the definition of scattering states in quantum field
  theory   The problem of extending quantum-mechanical formal scattering theory to a
more general class of models that also includes quantum field theories is
discussed, with the aim of clarifying certain aspects of the definition of
scattering states. As the strong limit is not suitable for the definition of
scattering states in quantum field theory, some other limiting procedure is
needed. Two possibilities are considered, the abelian limit and adiabatic
switching. Formulas for the scattering states based on both methods are
discussed, and it is found that generally there are significant differences
between the two approaches. As an illustration of the application and the
features of these formulas, S-matrix elements and energy corrections in two
quantum field theoretical models are calculated using (generalized)
old-fashioned perturbation theory. The two methods are found to give equivalent
results.

29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex