/SingleFieldINF_Powerspec_PBH

Primary LanguageJupyter Notebook

SingleFieldINF_Powerspec

We provide two seperate (pedagogical) Jupyter notebook files that compute the power spectrum of curvature perturbation,

  • In canonical single field inflationary scenarios that include a transient phase of non-attractor era: PowerSpec_CanonicalSF.ipynb
  • In generalized single field inflationary models that exhibit an effective time dependent Planck mass along with a non-trivial sound speed for the scalar curvature fluctuations: PowerSpec_GSF.ipynb

For the former, an effective (but accurate) parametrization of the background evolution is adopted where inflationary evolution has been modeled in terms of successive phases of slow-roll --> non-attractor --> slow-roll: see arXiv: 2301.03600 for details. Around this background solution, we then solve the Mukhanov-Sasaki (MS) equation for each mode in Fourier space which is essential for the computing the power spectrum of scalar fluctuations during inflation.

The program can be generalized to include a user defined scalar potential: by e.g adding an initial section that computes the background equations for a given scalar potential $V(\phi)$ followed by defining the relevant background / slow-roll parameters required for the solution of the MS equation.

For the latter, similarly to the canonical single field case, we adopt a phenomenological background model that exhibit a transient/localized slow-roll violation during inflation where the sound speed $c_s$ , effective time dependent Planck Mass $M$ and $\epsilon$ are all engineered to have a localized simultaneous dip.

The mode evolution in this case is determined by the generalized Mukhanov-Sasaki equation. Further details regarding the background and the mode evolution within the generalized single field models can be found in arXiv: 1811.03065 and 2301.03600

For any queries, please contact: ogan.ozsoy@csic.es