Dec 24 - Cosmic Bell Inequalities
arxiv.org/abs/1508.01082
Maldacena writes down a model of inflation where the statistics of certain hot and cold spots encode the outcome of a Bell-measurement. This shows that the quantum nature of inflation can survive in conventional classical observables
Dec 21 - Conformal Technicolor
arxiv.org/abs/hep-ph/0...
Luty & Okui rephrase the hierarchy problem as a statement about the relationship between the dimensions of operators. The idea is that the Higgs has a dimension near 1 but all the operators in its OPE have dimensions > 4.
We are announcing the *Early Universe from Home 2025* conference, whose registration is now open. Please share with colleagues and collaborators
Dec 14 - cosmological perturbation theory in 1+1 D
arxiv.org/abs/1502.07389
McQuinn and White study the evolution of structure in 1+1 dimensions, where the all-loop results can be calculated. They show SPT has a finite radius of convergence but doesn't converge to simulations.
Loved this pedagogical paper by John Donoghue
arxiv.org/abs/2412.087...
I feel like I need to break the ice here somehow... I suppose I will just announce that I will be posting my annual AxionLimits yearly round-up on this account soon, so stay tuned i guess
Dec 12 - A de Sitter S-matrix
arxiv.org/abs/1209.6039
Marolf et al. define an S-matrix for massive particles in (fixed) global dS. They prove that many facts about flat space S-matrix also apply to dS. They develop a lot of interesting ideas that should have a wide range of applications
Another favorite paper of mine. I have read and reread this paper multiple times
Dec 10 - Detectors and Rindler Particles
journals.aps.org/prd/abstract...
Unruh and Wald give a fantastically clear explanation of why accelerating observers see a thermal spectrum of particles: the particles are created from the energy you put into the detector to accelerate it.
Dec 9 - Axion-electron coupling limit from 47 Tucanae
arxiv.org/abs/1507.05665
Studying white dwarf cooling in this globular cluster, Hansen et al. bound the axion coupling g_ae < 8.4E-14. This excludes the hint of axion cooling seen in previous studies (eg arxiv.org/abs/0806.2807).
This has always been one of my favorite papers.
It’s #introduction time!
- I create universes using supercomputers as a job
- I’m eternally fascinated by all the mysteries of the cosmos
- currently trying to unveil some of the properties of dark energy
- passionate advocate for equity in science
Looking forward to interact with ya’ll!
Artist’s impression of the horizons and curvature of a binary black hole system. Generated using Paraview.
(1/7) As I’m new here I thought I should introduce myself!
My name is Olly Long and I am a researcher working on modelling the binary black hole problem in General Relativity.
Dec 8 - EFT / model building and the anomalous perihelion of mercury
arxiv.org/abs/1106.1568
Wells explores how a model building / EFT approach to explaining Mercury's orbit would have worked. He introduces 3 ideas that all can work, and are realized in GR in different gauges.
This is absolutely my favourite paper! I love it and I also had a little history in it because Scott talked to me about an idea of mine which evaded this strong constraint! Why is it such a beautiful paper ? Let’s discuss it! 1/n
Dec 7 - The Age of the Universe
arxiv.org/abs/astro-ph...
Combining data from CBI, DASI, BOOMERANG ++, Seivers et al. measure the age to be 13.7 +/- 0.2 billion years in near perfect agreement the modern value. This is when cosmology becomes a precision subject, giving tight errors on LCDM.
One of my favorite papers
Three PhD positions in theoretical physics 🧪⚛️ are open at the TPPC in King's College London with three excellent supervisors!
Dec 4 - An EFT for Holographic RG (Kaplan & Wang)
arxiv.org/pdf/1406.4152
This paper writes the non-relativistic EFT in AdS that is dual to a large class of relativistic RG flows on the boundary. The construction of the bulk theory is the AdS analogue of the EFT of Inflation.
I am looking for a PhD student for the OCT 2025 intake to work on dynamical compactification of extra dimensions or on boson stars GW signatures!
www.kcl.ac.uk/research/the...
Congratulations 💜💙
Dec 3 - Dark Energy Survey CMB-free H0 measurement
arxiv.org/abs/1711.00403
Combining BBN+BAO+weak lensing they measure H0 = 67.4 +/- 1.1 km/s/Mpc, in agreement with the CMB without using CMB data. This was the first measurement of its kind at essentially current day precision.
Dec 2 - Scattering to many particles is (semi)-classical
Eg inspirehep.net/literature/2...
arxiv.org/abs/hep-ph/9...
Two to N scattering is described by a semi-classical solution to the equations of motion (controlled by large N). This property of rare processes is far more general
Look out for 31 posts in Physics this month by Prof. Dan Green
My PhD supervisor (Varun Sahni) pointed this out to me very early on in my career. Strangely, it is quite underappreciated, as you pointed out.
Dec 1 - Peebles on dark matter and the CMB
ui.adsabs.harvard.edu/abs/1982ApJ....
Peebles explains how the lack of observations of CMB temperature fluctuations at dT/T > 10^(-3) requires dark matter. It was a decade before anyone measured a non-zero value but this connection is profound
I love many. This is my newest favorite
Sharing another intriguing physics paper :
I have long been fascinated by Paul Ehrenfest's 1917 article showing planetary systems are virtually unstable for any dimensions of spacetime, other than d = 3+1
[Proc. Amsterdam Academy. 20 200]
