What's new (past 12 months)

Version 3.6.2 available

Version 3.5.1 available

A paper on diagram generation with mixed propagators

Notice:   Between now and August there will be occasional, extended power cuts (mostly on a few weekends) for maintenance work on the electrical network which powers this website (and a lot more besides).

latest version:  3.6.2

Qgraf is a computer program that generates Feynman diagrams for various types of QFT models — it is a research tool created with the obvious aim of contributing to extend the range of feasible, perturbative QFT calculations. It generates neither 0-point nor non-connected diagrams, though.
Diagrams are represented by symbolic expressions only; however, if some kind of graphical representation is required, have a look at some of the external links (in the first group).

  • Latest version: qgraf-3.6.2 (2022).
    Please report any error you may happen to find.

  • Programming language: Fortran 2008 for versions released since 2020, and Fortran 77 for earlier versions.
    Executables/binaries are not distributed, the program has to be compiled and linked.
    Employing GNU Fortran for that task should be straightforward, eg there should be no need to specify a Fortran standard (see file qgraf-3.6.0.pdf).
    There are executable/binary versions of GFortran for several operating systems, as described in the GFortranBinaries webpage.

  • The features added in the last three versions include (eg):
    an option to select diagrams with non-factorizable cycle spaces (3.4);
    an option to select 1–vertex irreducible diagrams (3.4);
    the ability to generate multiple output files in the same run (3.5);
    an extended language for describing input models (3.6).

  • Current plans: qgraf-3.4 should be available and supported for some time yet (minimal fixes as need be); the long term status of qgraf-3.5 is uncertain at this moment, but it will not be ‘stable’ like qgraf-3.4; moreover, qgraf-3.1 should be considered obsolete, and (say) qgraf-3.4 its potential substitute.

Qgraf is based on the method described in the following paper:

  • Automatic Feynman graph generation
    J. Comput. Phys. 105 (1993) 279–289

    show outline

The diagram generation with mixed propagators can be reduced to the usual one:

  • Feynman graph generation and propagator mixing, I
    Comput. Phys. Commun. 269 (2021) 108103

    show outline