http://arxiv.org/abs/2212.00529
Cosmic inflation is a period of rapid accelerated expansion of space in the very early universe. During inflation, vacuum quantum fluctuations are amplified and stretched to cosmological scales which seed the fluctuations in the cosmic microwave background as well as the large-scale structure of our universe. Large quantum fluctuations may lead to the formation of primordial black holes (PBHs) in the post-inflationary universe. Numerical simulations of the inflationary dynamics are presented here for a single canonical scalar field minimally coupled to gravity. We spell out the basic equations governing the inflationary dynamics in terms of cosmic time $t$ and define a set of dimensionless variables convenient for numerical analysis. We then provide a link to our simple numerical Python code on GitHub that can be used to simulate the background dynamics as well as the evolution of linear perturbations during inflation. The code computes both scalar and tensor power spectra for a given inflaton potential $V(\phi)$. We discuss a concrete algorithm to use the code for various purposes, especially for computing the enhanced scalar power spectrum in the context of PBH formation. We intend to extend the framework to simulate the dynamics of a number of different quantities, including the computation of scalar-induced second-order tensor power spectrum in the revised version of this manuscript in the near future.
S. Bhatt, S. Mishra, S. Basak, et. al.
Fri, 2 Dec 22
51/81
Comments: 39 pages, 20 figures, GitHub link to codes provided in the paper, comments and suggestions are welcome