If you’re searching for a gift for someone who loves real science — not the click-bait shortcuts — Battle of the Big Bang might be the cosmic spark you’re looking for.

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The model is also fully consistent with the latest ACT/SPT measurements of the scalar spectral index, which increasingly disfavour Starobinsky inflation.

📄 Paper: arxiv.org/abs/2510.18733

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🚀 New(ish) paper!

With my student Ruolin Liu and Jérôme Quintin, we show how quadratic gravity can offer an ultraviolet completion of the Big Bang. Its renormalization group flow yields arguably the first UV-complete inflation model without ghost instabilities.

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What if the Big Bang wasn’t the beginning at all?

On Nov 10 @ 6:30 PM ET, I’ll join Lisa Randall at @harvard.edu Science Book Talks to discuss my new book Battle of the Big Bang.

science.fas.harvard.edu/event/harvar...

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🎃 Haunted Cosmology Celtic Tour: Dublin & Edinburgh 🕯️

This October, Phil and I are taking our ghost-hunting into the heart of cosmology.
Join us for a journey through cosmic ghosts, phantoms, and monsters — not from folklore, but from the deepest mysteries of physics.

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Time is running out to apply for our workshop:

"50 years of the black hole information paradox: November 3 -7 , 2025"

at Simons Center for Geometry and Physics

scgp.stonybrook.edu/archives/45328

#BattleoftheBigBang is having a party 🥳

How could we be stuck in a cosmic Groundhog Day?

Listen to our latest discussion on #BattleoftheBigBang

w/ @whattheif.bsky.social and @philhalper.bsky.social

Thank you very much Emma for taking this journey with us; I am glad and humbled that you enjoyed the #BattleoftheBigBang

#BattleoftheBigBang is finally here!

Take advantage of a 30% discount by using this discount code (UCPNEW) when ordering from:

press.uchicago.edu/ucp/books/bo...

We advocate going around the singularity (i.e. branch point) in the complex plane within our construction, so technically, our only boundaries are also at infinities, one Euclidean, and the other Lorentzian.

We call these complex powerballs, and discuss their probabilistic interpretation.

What happens when you fall into a complex geometry? Will there be observable signatures in astronomical or gravitational waves? Great questions! TBD

Credit: Ruolin Liu (🥳 1st lead author paper) and Jerome Quintin 💪💪

ChatGPT: Based on what you know of Niayesh Afshordi, draw a picture of what you think his life currently looks like

I am thrilled to announce that, after many years of writing and rewriting alongside my dear friend and science communicator par excellence,
@skydivephil
, our popular science book:
“Battle of the Big Bang: New Tales of Our Cosmic Origins”
is now available for pre-order ... (1/3)

More #aurora

#aurora

So long Rome, and thanks for all the fish! agenda.infn.it/event/37487/

Hello Kyoto! www2.yukawa.kyoto-u.ac.jp/~gc2024/inde...

create an image of a cosmologist who cannot sleep.

ChatGPT:

www.sfu.ca/physics/news...