The observable Universe as a multi-layered probe of fundamental physics

by Ely Kovetz

Ben-Gurion University

at Physics Colloquium

Tue, 02 Apr 2019, 15:30
Ilse Katz Institute for Nanoscale Science & Technology (51), room 015

Abstract

The standard model of cosmology, encapsulated by just a handful of parameters which describe the energy content of the universe, its rate of expansion, and the amplitude and scale-dependence of primordial perturbations, has been immensely successful when confronted with more than two decades of cosmological observations. However, this simple picture masks the extent of our ignorance regarding several fundamental questions in cosmology, such as what are the properties of inflation, what is the nature of dark matter, what is the form of dark energy and how did galaxies form and evolve.
I will briefly survey the different epochs in the history of the observable Universe and motivate the most promising experimental efforts to observe them that are planned for the next decade and beyond. Focusing on the search for dark matter, I will demonstrate how novel cosmological observables can probe models that lie on the extreme ends of its possible mass spectrum. One intriguing scenario for dark matter is that it is made up of massive primordial black holes formed in the early Universe. Placing an emphasis on the stellar-mass window motivated by the most recent LIGO detections, I will describe how astrophysical transients such as fast radio bursts can elegantly test the scenario. Dark matter can also consist of particles (much) lighter than the scale of weak interactions, which are inaccessible to terrestrial direct detection experiments. I will show that measurements of the neutral hydrogen 21cm emission line during cosmic dawn, the era in which the first stars in the Universe were born, are uniquely sensitive to interactions between the dark and visible sectors. In particular, I will discuss the suggested dark matter explanation for the recently claimed detection of an anomalous 21cm absorption profile by the EDGES experiment.

Refreshments are served at 15:15.

Created on 26-03-2019 by Kats, Yevgeny (katsye)
Updaded on 26-03-2019 by Kats, Yevgeny (katsye)