Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Comparison of relativistic bound-state calculations in Front-Form and
  Instant-Form Dynamics   Using the Wick-Cutkosky model and an extended version (massive exchange) of
it, we have calculated the bound states in a quantum field theoretical
approach. In the light-front formalism we have calculated the bound-state mass
spectrum and wave functions. Using the Terent'ev transformation we can write
down an approximation for the angular dependence of the wave function. After
calculating the bound-state spectra we characterized all states found.
Similarly, we have calculated the bound-state spectrum and wave functions in
the instant-form formalism. We compare the spectra found in both forms of
dynamics in the ladder approximation and show that in both forms of dynamics
the O(4) symmetry is broken.

7
The categories of this paper are: hep-th
17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics