Cliff Burgess

bsky.app/profile/cbur...

Thanks for the post - you beat me to it 😁

😳🥲

Many lovely collaborators on this: Adam Smith, @mmylova.bsky.social , Carsten van de Bruck and Eleonora Di Valentino.

INFLATION 2025 - Cliff Burgess YouTube video by Institut d'astrophysique de Paris

A recent talk about this is posted here. (The second part is about this.) youtu.be/tv5xuPtZ7is?...

There is a catch: the best fits predict a DE-matter coupling large enough to have been seen already in solar system tests of GR. For some reason the coupling now differs from the coupling favoured by cosmology in the past, so the main puzzle is figuring out why.

We are looking into whether this can also help explain earlier than expected formation of supermassive black holes and galaxies.

The evolution is not put in by hand and explains why BBN need not be a problem. Subsequent mass evolution does not ruin structure formation, but predicts more structure than LCDM and earlier transition from radiation- to matter-domination (and so more time for structure to grow).

The model is not designed at all to solve the Hubble tension but does so for free.

Although it has positive energy if applied to DESI results it behaves *as if* w < -1 (in the phantom zone)

It resolves Hubble tension bcs particle masses differ at recombination, as fields evolve.

Forgot the 🧪

The Serendipitous Axiodilaton: A Self-Consistent Recombination-Era Solution to the Hubble Tension Axio-dilaton cosmology provides a minimal benchmark model for both Dark Matter (DM) and Dark Energy (DE) that is well motivated by fundamental physics. The axion and dilaton arise as pseudo-Goldstone ...

The fit results are new and just came out here: arxiv.org/abs/2512.13544

Paper day. In a proposal last year we minimally describe the entire dark sector using two scalar fields, motivated by an approach to the cosmological constant problem.

We recently fit this model to cosmological data and find it works better than LCDM, because it resolves the Hubble tension.

To fathers everywhere. Enjoy it (and enjoy them) while you can 💕

Coffee break, snack and some bread ready for the oven

I understand pride in construction, but this might be a bit over the top

You also not a metric fan?😇

Doesn’t that mean that the data driven theory calculation was likely underestimating its uncertainties?

What problem gets solved by doing this?

It isn’t actually in any particular need of repair despite what you read on social media.

#HepJobs Junior faculty and post-doc positions in the @lhcb.bsky.social group at @tu-dortmund.bsky.social . Strong group, very involved in the trigger. Apply! inspirehep.net/jobs/2928524

This is a lovely experiment and all, but didn’t the resolution to this puzzle come from the theory side? 🧪⚛️

I think so

Next 48hrs NZ

🚨 Oh wow. Calling the side of the world where it's still dark. Look up!! Look up!! The mega sun burp has arrived 😮
#AuroraAlert

Notes: Get far away from streetlights & look for a silvery shimmer in the sky. Prop your smartphone up on a wall to take a long exposure & reveal the colours. 🤩 🔭🧪

Take pics!

Wildflowers in the woods last weekend

The attack on basic science in the USA is real:

The National Science Foundation just killed half of the Nobel prize winning LIGO experiments (essentially meaning: LIGO can no longer see where a gravitational wave comes from, just that it was there)

Only 600 citations? Better step up your game there Al…

Lovely! (On your way home through France?)

Yeah, and she conveniently lined herself up with the Eastern Redbud on the foreground 👍