Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Monte Carlo Calculation of Phase Shift in Four Dimensional O(4) $\phi^4$
  Theory   The phase shift of the O(4) symmetric $\phi^4$ theory in the symmetric phase
is calculated numerically using the relation between phase shift and energy
levels of two-particle states recently derived by L\"{u}scher. The results
agree with the prediction of perturbation theory. A practical difficulty of the
method for a reliable extraction of the phase shift for large momenta due to
the necessity of a precise determination of excited two-particle energy levels
is pointed out.

19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
6
The categories of this paper are: astro-ph
15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn