Nonperturbative evaluation of the few-body states for scalar chi- square phi interaction. C. Savkli.

PROGRAM SUMMARY
Title of program: phi3
Catalogue identifier: ADNO
Ref. in CPC: 135(2001)312
Distribution format: tar gzip file
Operating system: Unix
Number of lines in distributed program, including test data, etc: 1554
Keywords: Nonperturbative, Bound states, Feynman-Schwinger representation, Monte-Carlo, Numerical evaluation, Elementary particle physics, QCD.
Programming language used: Fortran
Computer: Sun 19 .

Nature of problem:
The program provided here evaluates the mass and distribution probabilities of the fully interacting n-body propagator (n<=3) for scalar chi-square phi interaction in 3+1 dimensions. The evaluation takes into account all self energy, vertex dressing, and exchange interaction contributions except those involving matter loops (the quenched approximation).

Method of solution:
The Feynman-Schwinger representation approach is used to express the field theoretical Green's function in terms of a quantum mechanical path integral. The resultant expression is evaluated using a Monte-Carlo simulation.

Restrictions:
Only n = 1, 2, and 3 body propagators are considered. The extension to n >= 4 requires straightforward modifications in the program.

Typical running time:
About 1 day for the 1-body propagator with the self energy.