The ESA Euclid experiment will map around a billion galaxies in the next six years and give us new insights into the properties of Dark Matter and Dark Energy. Today, Euclid released its first pictures: Euclid’s first images.

# Category Archives: Physics

Not all approaches to the Hubble tension are equally good or bad. Some recent discussion seems to ignore the fact that early-time approaches like New Early Dark Energy also fit the CMB better than Lambda-CDM independent of the Hubble tension ( https://arxiv.org/abs/2305.08895 ).

Nice paper from Kyoto today, https://arxiv.org/abs/2309.02288, emphasizing that small-scale inhomogeneities are unlikely to play a relevant role in understanding the Hubble tension. This also follows from classic papers like BNSZ’s https://arxiv.org/abs/1004.2488 and Peebles https://arxiv.org/abs/0910.5142

Nice informative result in today’s paper; the old Early Dark Energy model struggles to address the S8 tension (https://arxiv.org/abs/2309.00401). This singles out New Early Dark Energy, a triggered phase transition in the dark sector, as a possible minimal resolution to both the H0 and the S8 tensions — see f.ex. https://arxiv.org/abs/2305.08895.

Quote from today’s review of the local H0 measurements: JWST “observations provide the strongest evidence yet that systematic errors in HST Cepheid photometry do not play a significant role in the present Hubble Tension”: https://arxiv.org/abs/2308.10954

Groningen group with a new paper *not* finding evidence of unknown systematics being the source of the Hubble tension. This further strengthens the case for early times (pre-recombination) new physics, like New Early Dark Energy (NEDE): https://arxiv.org/abs/2308.05157

A reminder not to believe we know it all and not to stop exploring the wonders that nature might hide for us.

Niels Bohr, in conversation with Robert J. Oppenheimer.

New review article with Florian Niedermann: “New Early Dark Energy as a Solution to the H0 and the S8 Tensions:” https://arxiv.org/abs/2307.03481. Contributed chapter to the book “Hubble Constant Tension.”

“NANOGrav meets Hot New Early Dark Energy and the origin of neutrino mass”: We show that in the Hot NEDE model, both the Hubble tension and the NANOGrav observations could be a signature of the origin of neutrino mass: https://arxiv.org/abs/2307.03091