PresentationThis project aims at developing tools for predicting and computing cosmic density spectra and bispectra (three-point correlation function) for a large set of cosmological models that include non-standard effects such as massive neutrinos or clustering dark energy. More precisely we wish to build theoretical tools for predicting those quantities analytically and with a controlled precision in the quasilinear regime and develop robust and fast numerical codes for computing a set of well defined observables such as those related to cosmic shear observations, redshift space density field, etc. We also wish to construct more phenomenological models that explore the relationships between the density field (and its various components) and the halo density.
The approaches we favor in this project make use of computation techniques that have been recently put forward in which re-summations of large classes of diagrams can be taken into account. These approaches explicitly, or implicitly, take advantage of the so-called eikonal approximation. Those approaches allow to develop perturbation theory calculations in a controlled way and for a large class of observables such as spectra, bispectra etc. Our project aims at writing and releasing packages - in fortran to make its portability to different systems easier - for the fast computation of perturbation theory spectra and bispectra beyond linear theory. More precisely, we wish to develop codes that compute spectra up to 2 loops (NNLO) and bispectra up to 1 loop (NLO).
State of the art and available codes
Public codes for fast computations of power spectra at 2-loop order are now available. There are currently two proposed versions (see accompanying papers)
MPTBreeze : Code to compute power spectra from multi-point expansions. It is based on the prescription described in MPTbreeze: A fast renormalized perturbative scheme, arXiv.org/1207.1465
RegPT : Code to compute cosmological power spectra using the regularized method based onThe MPTbreeze and RegPT codes are free software: you can redistribute it and/or modify it at your own risk. This program is distributed in the hope that it will be useful in scientific research, but without any warranty.
Partners and ongoing developmentsAll project members can be reached via email. At the IPhT collaborators are involved in various aspects of the extension of the methods and content of the universe,
Finally exploration of alternative statistical tools are also done with
CalendarThe next milestones for the collaboration are
Of special interests for the collaboration :
Previous meeting directly related to the project are listed below. Relevant material can be found on their web sites,