MULTIMODECODE : an efficient numerical solver for multifield inflation

作者：Price Layne C^*; Frazer Jonathan; Xu Jiajun; Peiris Hiranya V; Easther Richard

来源：Journal of Cosmology and Astroparticle Physics, 2015, 2015(3): 005.

DOI：10.1088/1475-7516/2015/03/005

• inflation
• cosmological perturbation theory
• initial conditions and eternal universe
• physics of the early universe

We present MULTIMODECODE,(1) a Fortran 95/2000 package for the numerical exploration of multi field inflation models. This program facilitates efficient Monte Carlo sampling of prior probabilities for inflationary model parameters and initial conditions and is the first publicly available code that can efficiently generate large sample-sets for inflation models with O (100) fields. The code numerically solves the equations of motion for the background and first-order perturbations of multi-field inflation models with canonical kinetic terms and arbitrary potentials, providing the adiabatic, isocurvature, and tensor power spectra at the end of inflation. For models with sum-separable potentials MULTIMODECODE also computes the slow-roll prediction via the delta N formalism for easy model exploration and validation. We pay particular attention to the isocurvature perturbations as the system approaches the adiabatic limit, showing how to avoid numerical instabilities that affect some other approaches to this problem. We demonstrate the use of MULTIMODECODE by exploring a few toy models. Finally, we give a concise review of multi field perturbation theory and a user's manual for the program.

• 出版日期2015-3