New paper with Mathias Garny, Florian Niedermann, and Henrique Rubira. We show that Hot NEDE provides a UV completion of SIDR and stepped models, bringing them in agreement with the BBN constraints when addressing the Hubble tension: https://arxiv.org/abs/2404.07256

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Exciting new results from DESI today on the large-scale structure of the universe and the measurement of baryonic acoustic oscillations (BAO). The first takeaway relating to New Early Dark Energy (NEDE) as a solution to the Hubble tension is the product of the drag-epoch sound horizon and the scaled Hubble constant of rdh = (101.8 ± 1.3) Mpc, slightly higher than previous measurements.

This might mean that one needs a smaller reduction of the sound horizon to achieve the same increase of H0—as illustrated by superimposing (by eye on the iPad) the constraint on the plot of Know and Millea from 2019 below — making it marginally easier to resolve the Hubble tension within NEDE.

Opportunity for advanced post-doc level researchers to set up their own group in Denmark (see below). If you work within the (one of the) fields of particle physics, cosmology, astroparticle, (quantum-) gravity, or astronomy, feel free to contact me directly.

https://villumfonden.dk/en/group/grantsubarea/villum-young-investigator

An interview with me about the origin of the Universe and Dark Energy was aired today on Danish Radio4. We also got to talk about, among others, the Hubble tension and New Early Dark Energy (NEDE). Below is a link to the full interview (in Danish).

”LIVET: Sådan blev universet skabt” blev sendt kl. 12.10 til 13.00 på Radio4 d. 25. december: https://radio4.dk/podcasts/kraniebrud/livet-s-dan-blev-universet-skabt

An interesting paper from this morning, https://arxiv.org/abs/2312.11074, points out that (N)EDE-type models could potentially also resolve the problem of early galaxy formation found by JWST, as was also hinted at in a previous study https://arxiv.org/abs/2208.01611. The authors point out that the region of (N)EDE parameter space required for solving the JWST problem is the same region of (N)EDE parameter space needed for solving the H0 tension.

Check out the excellent talk by my collaborator, Florian Niedermann, on New Early Dark Energy (NEDE) in the CosmoVerse seminar series linked below.

Two interesting new papers:

One indicates that new physics in the dark sector at the two scales, the eV scale and a ULA scale, close to those inherent in the Cold NEDE solution to the Hubble tension, could be required by eBOSS Lyman-alpha data https://arxiv.org/abs/2311.16377.

And one that constrains a corner of NEDE parameter space in more detail from the microphysics of the phase transition https://arxiv.org/abs/2311.16222, emphasizing the requirement of a fast phase transition.

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.

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