CARAVEL: A C plus plus framework for the computation of multi-loop amplitudes with numerical unitarity

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 summary 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: center dot Required: Python3 [1], meson [2] center dot 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. References [1] http://www.python .org/ [2] https://mesonbuild .com/ [3] http://www.doxygen .nl/ [4] http://eigen .tuxfamily.org/ [5] https://ginac .de/ [6] https://gmplib .org/ [7] http://www.netlib .org /lapack/ [8] https://www.mpfr.org/ [9] https://www.open -mpi .org/