What would really be the implications of taking Santa Claus seriously? It's the time of the year to review the current state of the physics of Santa Claus 1/12
Martin Bauer
@martinmbauer.bsky.social
I'm a theoretical physicist at Durham University
Really interesting event that would require black holes thatcan't be produced via any conventional mechanism!
Christopher Berry@cplberry.bsky.social · 9mo agoOo! Interesting #GravitationalWave candidate #S251112cm potentially from a *subsolar* mass source If real, the source is probably has chirp mass ~0.1–0.87 solar masses False alarm rate 1 in 6.2 yr GraceDB gracedb.ligo.org/superevents/... GCN gcn.nasa.gov/circulars/42... Rating 📏🍬 [🧪🔭⚛️]
The hierarchy problem (finetuning) of the Standard Model of particle physics is often presented as the question 'why the weak scale is so much smaller than the Planck scale' But there is also a geometric interpretation that can be understood with little maths (but a lot of physics) 🧵1/11
Short explanation of the physics Nobel Prize 2025 In classical mechanics you can know where a particle is and its momentum at the same time. In Quantum mechanics you can't. All information is in the wavefunction. Even if a particle is trapped, part of the wavefunction.. 🧵1/7
This night 102 years ago, Hubble discovered that there're stars outside our galaxy by observing a Cepheid variable star 1 million light years away Until barely a century ago, no human ever knew whether there was more than one galaxy in the Universe. Think about that!
Today LHCb presented a new measurement of the decay of a B meson into a K* and a μ+ μ- pair Previous results disagreed with the Standard Model prediction for the branching fraction and angular distribution The new measurement has almost twice as much data and still disagrees! 🧵1/6
In 3 (or more) dimensions, all fundamental particles are either fermions and bosons. But why? This is a direct consequence of the properties of the configuration space for identical particles 🧵 1/14
Here is it: The worlds best measurement of the anomalous magnetic moment of the muon In great agreement with previous experimental results and in agreement with the Standard Model prediction using the LO HVP contribution from lattice input
Livestream of the final result of the anomalous magnetic moment of the muon measurement at Fermilab right now: www.youtube.com/watch?v=huLv...
Final Muon g-2 Measurement at Fermilab
YouTube video by Fermilab
youtube.com
Before the charm quark was discovered in bound states, it was predicted via indirect effects. An early success story of the electroweak model and QFT! Mary Gaillard and John Rosner, who both passed last week, contributed to calculating the charm quark mass 🧵1/11
Even if you don't care one bit about scientific research, it's important to recognise the value of publicly funding people working on very hard problems and training bright young minds on how to solve them.
Excellent news: Germany invests €200M in fundamental physics, funding clusters in Mainz, Siegen, Bonn, Dortmund, Munich & Hamburg focused on particle physics, astrophysics & cosmology The selection of *all* fundamental physics finalists marks a major boost in support! www.dfg.de/de/service/p...
Entscheidungen in zweiter Wettbewerbsrunde der Exzellenzstrategie: Exzellenzkommission wählt 70 Exzellenzcluster aus
dfg.de
Are neutrinos their own anti-particles? They are the only fundamental fermions that could have this unique property. But they're so elusive, how could we figure that out? A brilliant experiment could answer this question without detecting a single neutrino 🧵1/11
Does quantum mechanics really need to be complex? Why can't we just use real wavefunctions? 🧵1/15 *some math, non-relativistic QM
The proton (uud) is lighter than the neutron (udd) because the up quark is lighter than the down quark. Then why is the delta resoncance Δ++ (uuu) heavier than both? This can be fully understood via a symmetry argument 1/12
Renormalisation is a central concept in modern physics. It describes how the dynamics of a system change at different scales. A great way to understand and visualise renormalisation is the Ising model (some math, but one can follow without it ) 1/13
A search for additional Higgs bosons has found evidence for Toponium, a bound state from top quark-antiquark pairs that has the mass of two gold atoms, decays in 5x 10^-25 s and 1% the size of a proton. This wasn’t expected to be observable at the LHC cerncourier.com/a/cms-observ...
CMS observes top–antitop excess – CERN Courier
The signal could be caused by a quasi-bound top–antitop meson commonly called "toponium".
cerncourier.com
Physicists in Innsbruck have shown for the first time that it is possible to create quantum superpositions from thermally excited states (mixed states instead of pure states) phys.org/news/2025-04...
Hot Schrödinger cat states
A thermal initial state with low quantum purity is put into a superposition of displacements, while retaining its entropy.
science.org
All supernovas ever observed, tens of thousands of dying stars Once the Rubin Observatory is completed it will be able to see several millions of supernovas, dwarfing what we've seen so far This is from a brilliant website by Isaac Shivvers. ishivvers.github.io/maps/sne.html
Big fan of this description of science from @martinmbauer.bsky.social I like that it accurately captures the role of so-called "giants", as people who see the structure of large amounts of previous work of the innumerable vital scientists who usually don't make it into the history books
Do you want to see what it'd look like to fly through the DESI map of the Universe? Our Universe is absolutely huge. Each dot here is a galaxy with hundreds of billions of stars. www.youtube.com/watch?v=fQkF...
DESI Galaxy Flight with captions
YouTube video by Fiske Planetarium
youtube.com
What happens if a planet gets too close to a white dwarf? Data from NASAs X-ray telescope Chandra suggest a white dwarf only 650ly from earth is slowly ripping a planet apart via tidal forces. This could explain variations in the X-ray spectrum observed since the 80s chandra.si.edu/photo/2025/h...
Excellent FAQ on the Majorana qubit chip from Microsoft by Scott Aaronson: scottaaronson.blog?p=8669
FAQ on Microsoft’s topological qubit thing
Q1. Did you see Microsoft’s announcement?A. Yes, thanks, you can stop emailing to ask! Microsoft’s Chetan Nayak was even kind enough to give me a personal briefing a few weeks ago. Yest…
scottaaronson.blog
The most energetic neutrino ever observed just smashed into the Mediterranean and left a signal that was picked up by the K3Mnet neutrino telescope 2400m under the sea At the moment we don't really know where this neutrino came from, nor should they really be there. A short 🧵1/10
Ep3 of the "Case for a new collider" series is out! Why is mapping the Higgs potential at a new collider so important? Such a mapping may allow us to understand how the universe may end and why we are even here to ask any questions at all. 🧪⚛️ Link: youtube.com/playlist?lis...
Really interesting interview with the incoming Director General cerncourier.com/a/a-word-wit...
A word with CERN’s next Director-General – CERN Courier
Mark Thomson, CERN's Director General designate for 2025, talks to the Courier about the future of particle physics.
cerncourier.com
The US government now instructs CDC scientists to withdraw, halt or remove their names from research papers that are currently in the publication process to screen the language for "forbidden terms" So much for free speech. www.reuters.com/world/us/us-...
US CDC orders pullback of new scientific papers involving its researchers, source says
The U.S. Centers for Disease Control and Prevention is seeking to withdraw all papers involving its researchers that are being considered for publication by external scientific journals to allow for a review by the Trump administration, a federal official told Reuters.
reuters.com