Cosmology
Cosmological observables
Tomislav Prokopec · Utrecht University
Most of us have gazed at the night sky, counted stars, and perhaps tried to
identify familiar patterns and structures. In doing so, we have already taken the first step towards
what modern observational cosmologists do: mapping the positions, shapes, sizes, and masses of distant
galaxies and studying how they are distributed across the Universe. These measurements constitute
cosmological observables.
A fundamental question is therefore: What physical processes gave rise to
the galaxies and the large-scale structure of the Universe, and what determines their observed
properties, including their distribution, shapes, and masses?
In this talk, I will discuss the leading theoretical framework for answering
this question: the amplification of quantum vacuum fluctuations during cosmological inflation.
According to this picture, microscopic quantum fluctuations in the early Universe were stretched to
cosmological scales during inflation and subsequently evolved into the primordial perturbations from
which galaxies and the large-scale structure eventually formed. We understand this mechanism remarkably
well when interactions are neglected. The situation becomes much more involved once interactions with
matter and gravity are included.
In this talk, I will present a program aimed at addressing this problem:
developing a systematic framework for computing cosmological observables from interacting quantum
cosmological perturbations, including their interactions with both matter and gravity. I will explain
the conceptual and technical challenges involved and discuss the pitfalls that arise when attempting
to make this connection between the fundamental quantum dynamics of the early Universe and the
structures we observe in the sky.
Slides (PDF) ›