This is a Mathematica package for high precision computation with the Effective Field Theory of Post-Newtonian Gravity. Its aim is to provide computer-algebra tools that can be used to derive analytical input for gravitational-wave source modelling relevant to current observatories. An example application provided with the code is the derivation of all currently known spin-dependent conservative interaction potentials in the post-Newtonian (PN) approximation to General Relativity (GR).
For a nontechnical description of the package and supplementary documentation see arxiv.org:1705.06309.
You need Mathematica and the xTensor package. For the latter, follow its installation instructions. Then, of course, clone this repository:
git clone https://github.com/miche-levi/pncbc-eftofpng.git
The package is modularized into several .m files. In order to run the standard examples, successively open the files with the Mathematica interface and click "Run Package" on the top-right corner, in the following order:
- FeynRul.m - compute Feynman rules
- FeynGen.m - generate Feynman diagrams
- NLoop.m - compute master integrals
- EFTofPNG.m - calculate the post-Newtonian Lagrangian
A good starting point to explore the code is the example calculation of the
2PN point-mass Lagrangian in the section FeynComp of EFTofPNG.m. The Feynman
diagrams are stored in a variable L2PNdiagrams, you can visualize them
with MakePNGraphs[L2PNdiagrams].
The code is designed in a manner that is very extensible to new applications. Yet this requires experience with Mathematica. The code is not a black box that can write a paper for you. We invite you to join in and participate in extending the code for further nontrivial applications that you have in mind.
You can find the (conservative) post-Newtonian GR Lagrangian including all currently known spin-dependent potentials in results/LEFT.dat.m.
Please read the file CodingStyle.m. Feedback and feature requests are also very much appreciated.
- Michele Levi - miche-levi
- Jan Steinhoff - jsteinhoff
This project is licensed under the GPL version 3, see the COPYING file.
It would have been much more difficult to create such a flexible package without building on the xTensor package. Let's all share our codes, so everyone can focus more on science!