My thoughts on what the Hubble tension really is, based on George Efstathiou’s “To H0 or not to H0?“, arXiv:2103.08723.
This week’s entry features a new ACT CMB lensing cross BOSS CMASS galaxies cross-correlation measurement implementing a new tSZ-cleaning procedure, a new update on the H0 tension and in particular how fifth forces could lower the TRGB-calibrated measurement (besides the usual Cepheid-calibrated one), and finally the return of black hole shadows (in asymptotically de Sitter spacetime). Enjoy and stay safe!
For a change, no H0 tension in this week’s entry (although I briefly touch on a new H0 measurement in paper 1)! This week I cover a new way to measure cosmological distances, a new dark matter candidate from an alternative to black holes, and the first calculation of how the neutrino Casimir force depends on the Dirac vs Majorana nature of neutrinos. Enjoy, and stay at home!
This week’s entry is dedicated to the H0 tension and attempts to solve the latter through early dark energy (possibly going beyond General Relativity), as well as to how a mysterious phenomenon known as skyquakes could be connected to an exotic model of dark matter known as axion quark nuggets. I hope this post will provide you a bit of entertainment (hopefully at home) in this time of uncertainty due to COVID-19.
With a week of delay, due to my recent travels to Norway, my Week 10 arXiv summaries are out! This week’s papers are all more or less related to dark matter, covering the particle physics, gravitational waves, and cosmology side of the story. Enjoy, and note that Week 11’s summaries are out too!
On Tuesday I found out that my PhD thesis has been awarded a “Springer Thesis Award”! This comes with a small amount of money and, most importantly, means that my thesis will be re-published as a book and e-book as part of the Springer Theses series. This series brings together a selection of the very best PhD theses from a strictly limited number of high-ranking university research departments in the physical sciences and engineering.
In this week’s summaries I look at vector-tensor Horndeski gravity (the lesser known sibling of scalar-tensor Horndeski gravity), the (im)possibility of solving the Hubble tension with late-time transitions in the dark energy, and a reconstruction of the time-dependent interaction between cold dark matter and vacuum energy. Note the possibility that next week’s entry might be cancelled or in the best case delayed (see my away note).
The common denominator between the 3 papers I selected this week is that they all are, to some extent, provocative, although related to completely different topics (respectively the Hubble tension, possible hints for dark matter in low-threshold direct detection experiments, and the possible need to move beyond archaic units in cosmology). I won’t say anything more to not spoil the fun, so enjoy reading!
This post is meant to advertise both my book review which just appeared in Nature Astronomy, as well as the book I reviewed. Two months ago Nature Astronomy asked me to write a book review on The Cosmic Revolutionary’s Handbook, a new popular science book by Luke A. Barnes and Geraint F. Lewis to be published by Cambridge University Press (one of the oldest and most prestigious publishing houses in the world) in March.
