CosmoPhys

A KITP-UCSB program running from Jan 6 to Mar 13, 2020 is an excellent resource for topics related to primordial universe cosmology (e.g., inflation, reheating (aka the Hot Big Bang), baryogenesis, non-gaussianity, dark sectors, cosmological sources of gravitational waves, Hubble tension, etc). The program agenda with links to videos and slides is here.

I'd like to point out an excellent overview talk from this program by Raphael Flauger on Feb. 28 that reviews Hubble measurement physics and results from each of the major determination methods and discusses current status on Hubble tension. The video for Flauger's talk is here. That page does not have the talk slides (at least not yet anyway) but the slides are available in PDF format here. Update: the slides are also now available on the KITP video page. Here is a PDF of the slides.

In the cosmology subreddit that I'm a member of, there are frequent questions from those who have a grasp of the basics and are keenly interested in learning more about cosmology but do not work in the field themselves. I especially want to give a shout-out about this talk to that group. It's an excellent and reasonably accessible review of a key trending problem-area needing resolution for there to be a better understanding of whether adjustments are needed to the ΛCDM standard model of cosmology. This overview talk very clearly summarizes what would otherwise take hours and hours of digging to get. The rest of the program has very good material but some of it is rather specialized and deep.

A recent discussion in this reddit thread contrasted differing takes within the community on whether inflation preceded or followed the big bang. There are various reasons for this, some of it having to do with the history and evolution of what is meant by the term 'big bang', which was also explored in this earlier thread.

Here are comments from the overview page for this KITP program on this: “inflation not only explains the large-scale homogeneity and isotropy of the Universe, but also provides a causal mechanism that results in the seeds for the subsequent growth of structure. However, what happens after inflation remains poorly understood. The end of inflation must provide a hot Big Bang, also known as reheating, which eventually must lead to a thermal bath of Standard Model particles, dark matter, and any additional Beyond the Standard Model (BSM) sectors, at least by the time of nucleosynthesis.”

Tags: #Cosmology #H0 #Talks