iiinova — where your digital self keeps evolving

Cliff Burgess @cburgescliff.bsky.social · 13/07/2026

Such terrible news. Lost one of the Good Ones. RIP Mark

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Cliff Burgess @cburgescliff.bsky.social · 18/12/2025

Thanks for the post - you beat me to it 😁

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Cliff Burgess @cburgescliff.bsky.social · 18/12/2025

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

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Cliff Burgess @cburgescliff.bsky.social · 18/12/2025

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

youtu.be

INFLATION 2025 - Cliff Burgess

YouTube video by Institut d'astrophysique de Paris

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Cliff Burgess @cburgescliff.bsky.social · 18/12/2025

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.

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Cliff Burgess @cburgescliff.bsky.social · 18/12/2025

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

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Cliff Burgess @cburgescliff.bsky.social · 18/12/2025

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).

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Cliff Burgess @cburgescliff.bsky.social · 18/12/2025

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.

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Cliff Burgess @cburgescliff.bsky.social · 18/12/2025

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.

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Cliff Burgess @cburgescliff.bsky.social · 15/06/2025

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

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Cliff Burgess @cburgescliff.bsky.social · 15/06/2025

Coffee break, snack and some bread ready for the oven

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Cliff Burgess @cburgescliff.bsky.social · 08/06/2025

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

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Cliff Burgess @cburgescliff.bsky.social · 06/06/2025

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

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Cliff Burgess @cburgescliff.bsky.social · 04/06/2025

What problem gets solved by doing this?

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Cliff Burgess @cburgescliff.bsky.social · 04/06/2025

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

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Reposted by Cliff Burgess

Patrick Koppenburg 🐧 @koppenburg.ch · 04/06/2025

#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

inspirehep.net

INSPIRE

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Cliff Burgess @cburgescliff.bsky.social · 04/06/2025

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

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Reposted by Cliff Burgess

Astronomer Royal for Scotland | Catherine Heymans @astroroyalscot.bsky.social · 01/06/2025

🚨 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. 🤩 🔭🧪

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Cliff Burgess @cburgescliff.bsky.social · 31/05/2025

Wildflowers in the woods last weekend

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Reposted by Cliff Burgess

Freya Blekman @freyablekman.bsky.social · 31/05/2025

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)

nsf-gov-resources.nsf.gov

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Cliff Burgess @cburgescliff.bsky.social · 30/05/2025

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

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Cliff Burgess @cburgescliff.bsky.social · 24/05/2025

Lovely! (On your way home through France?)

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Cliff Burgess @cburgescliff.bsky.social · 08/05/2025

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

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Cliff Burgess @cburgescliff.bsky.social · 28/04/2025

Glorious day Sunday. Wish I could convey the fragrance too

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Cliff Burgess @cburgescliff.bsky.social · 23/04/2025

I did notice you return to that sometimes 😇

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Reposted by Cliff Burgess

David Corn @davidcorn.bsky.social · 13/04/2025

Area Man Claims To Be Strongest Leader in World But Can’t Ask El Salvador a Favor

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Cliff Burgess @cburgescliff.bsky.social · 13/04/2025

AI in opera? Did not know that was a thing

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Cliff Burgess @cburgescliff.bsky.social · 13/04/2025

Are your external letters also supposed to be anonymized? 😳

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Cliff Burgess @cburgescliff.bsky.social · 11/04/2025

Oh yeah, I did leave that list lying about…😁

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Cliff Burgess @cburgescliff.bsky.social · 10/04/2025

Yeah, that realization kind of sneaks up on you 😁

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Cliff Burgess @cburgescliff.bsky.social · 07/04/2025

Trump’s sanctions against the US seem to be working…

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Cliff Burgess @cburgescliff.bsky.social · 04/04/2025

I think how you interpret things depends on whether you are just looking at the data and asking what it points you to, vs having a proposal motivated by other things that also predicts what the data sees.

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Cliff Burgess @cburgescliff.bsky.social · 02/04/2025

Thanks for pointing that one out! (Wish I had read it earlier😳)

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Cliff Burgess @cburgescliff.bsky.social · 02/04/2025

What is tantalizing is the model of the OP also has other features hinted at in cosmological tensions, such as polarization (DM is an axion) and an electron mass that differs near recombination (as can be relevant to the Hubble tension), though the model was not designed with either in mind.

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Cliff Burgess @cburgescliff.bsky.social · 02/04/2025

General power counting arguments show that it is these 2-derivative sigma model interactions that like to compete at low energies with the 2-derivative interactions of GR, so should be expected to be important arxiv.org/abs/0902.4465

arxiv.org

Power-counting and the Validity of the Classical Approximation During Inflation

We use the power-counting formalism of effective field theory to study the size of loop corrections in theories of slow-roll inflation, with the aim of more precisely identifying the limits of validit...

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Cliff Burgess @cburgescliff.bsky.social · 02/04/2025

The DM/DE interaction that does this is quite generic - it is just a sigma model interaction appropriate for curved target spaces - but only in models with two or more scalars (which is why Horndeski theories and vanilla quintessence models all miss it).

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