Caravel: A C++ framework for the computation of multi-loop amplitudes with numerical unitarity
S. Abreu, J. Dormans, F. Febres Cordero, H. Ita, M. Kraus, B. Page, E. Pascual, M.S. Ruf, V. Sotnikov
Abstract
We present the first public version of Caravel, a C++17 framework for the computation of multi-loop scattering amplitudes in quantum field theory, based on the numerical unitarity method. Caravel is composed of modules for the D-dimensional decomposition of integrands of scattering amplitudes into master and surface terms, the computation of tree-level amplitudes in floating point or finite-field arithmetic, the numerical computation of one- and two-loop amplitudes in QCD and Einstein gravity, and functional reconstruction tools. We provide programs that showcase Caravel's main functionalities and allow to compute selected one- and two-loop amplitudes. Program Title: Caravel CPC Library link to program files: https://doi.org/10.17632/rfjrxrb3rk.1 Developer's repository link: https://gitlab.com/caravel-public/caravel.git Licensing provisions: GPLv3 Programming language: C++ External dependencies: • Required: Python3 [1], meson [2] • Optional: Doxygen [3], Eigen [4], GiNaC [5], GMP [6], Lapack [7], MPFR [8], MPI [9], PentagonLibrary [10, 11], QD [12] Nature of problem: The computation of multi-loop multi-particle scattering amplitudes in quantum field theory Solution method: The multi-loop numerical unitarity method, functional reconstruction algorithms Additional comments including restrictions and unusual features: Current version includes tools employed in previous calculations, with the aim of showcasing details of the algorithms employed. Computations are organized by provided data files. http://www.python.org/ https://mesonbuild.com/ http://www.doxygen.nl/ http://eigen.tuxfamily.org/ https://ginac.de/ https://gmplib.org/ http://www.netlib.org/lapack/ https://www.mpfr.org/ https://www.open-mpi.org/ T. Gehrmann, J. M. Henn and N. A. Lo Presti, JHEP 1810 (2018) 103, arXiv:1807.09812 [hep-ph] https://gitlab.com/caravel-public/pentagon-library QD: A double-double and quad-double package for Fortran and C++, https://www.davidhbailey.com/dhbsoftware/