Contact: rhb[AT]physics.mcgill.caLocation: Ascona, Switzerland
Ascona Workshop 2025: Back-reaction Effects on Cosmological Observables
Place and Date: June 22 – 25 2025 at Congressi Stefano Franscini in Ascona, Switzerland
Overview
Observational cosmology has entered a golden age. Windows to probe the universe such as the cosmic microwave background (CMB) and large-scale galaxy surveys (LSS) have become precision science, and new windows such as 21cm redshift surveys with radio telescopes are opening up. In light of these advances in observational cosmology, the challenges on theoretical cosmology have grown rapidly.
The standard first-order linear perturbation theory, which is the current main tool in the literature, has been pushed to its limits, and improved approaches are needed in interpreting precision measurements in observational cosmology.
Beyond linear order in perturbations, fluctuations on any particular physical scale obtain contributions from other Fourier modes, which are independent in the linear regime. Of particular interest among these nonlinear effects to cosmological observations are so called “back-reaction effects, by which both short wavelength non-linear fluctuations affect the larger scale modes and hence the background evolution in large-scale structure of the Universe. There are also back-reaction effects of long wavelength linear modes on the modes which are currently measured in observations.
The aim of this workshop is to bring together experts working on various aspects of back-reaction problems, with particular emphasis on computing the effects on measurable quantities which are based on light cone averages.
Participation: by invitation only
Interested participants please contact either
Robert Brandenberger rhb[AT]physics.mcgill.ca
Jaiyul Yoo jaiyul.yoo[AT]uzh.ch