I was saddened to hear of Michael Hall's passing. Over the years he offered me both encouragement and thoughtful scientific advice, most recently last December. A great scientist and a rare model of kindness and integrity in academia, he will be greatly missed.

New blog post. This is about macroscopicity and "inferential reference frames". quantumquia.com/2025/12/16/w...

I just received a paper for a Springer journal that was obviously LLM-generated, complete with non-existent theorems, missing proofs, and hallucinated references. The journal has double-blind review. You see the problem? Stone thrown, hand hidden. No one to name-shame.

Can I call them quantum panini relative entropies instead of sandwiched?

New blog post about the quantum Bayes rule paper, joint work with with Ge Bai and @valerioscarani.bsky.social quantumquia.com/2025/10/08/b...

Whenever I see the scoring letters "SABC," I read "soprano, alto, tenor, bass" instead.

Tomorrow will be Cornell Information Theory Day, with program available here: find.engineering.cornell.edu/cornell-info... Book of abstracts here: find.engineering.cornell.edu/files/2025/0...

MDPI are running out of nouns in the English dictionary for the titles of their journals

After about two decades of friendship, I now realize that there's a "Nicholas" between "Jeremy" and "Butterfield." arxiv.org/abs/2505.23639

I received this email from Scipost and thought I would share it here. It's an open letter to the scientific community asking for help to keep Scipost alive and sustainable. (It's a bit long, so I'm sharing it as a public link in my Evernote). share.evernote.com/note/dc4f9e1...

Refs : - clintel.org/nobel-prize-... - co2coalition.org/publications...

I'm a huge fan and an active user of the hyperref and cleveref LaTeX packages, but unfortunately it looks like they are no longer compatible (and cleveref is not actively maintained). github.com/latex3/hyper... Any suggestions for cleveref alternatives? (Or anyone able to maintain it...?)

HISTORY OF PHYSICS On fear, by Paul Dirac. I would like to refer particularly to Lorentz. Any of you who have studied relativity must surely have wondered why it was that Lorentz succeeded in getting correctly all the basic equations needed to establish 1/

Forer's statements, psychic cons, and AI softwarecrisis.dev/letters/llme...

I finally got my hands on Lanczos' "The Variational Principles of Mechanics". I'm very excited to dive into it!

Two things bothered me when discussing "quantum non-Markovianity". First, that there was no way to exclude classical processes. Second (but related to the first), that a simple mixture of two Markov processes could turn out to be non-Markovian.

Let's see what happens if I spoof the article metadata from the backend... www.bbc.co.uk/news/article...

Since I gave an overview presentation on the Petz transpose map in 2021, we've learned a lot more about its interpretation and relation to Bayesian inversion. The most important, in my opinion, is the derivation of the Petz transpose map from a principle of minimum change. youtu.be/8ZzGI7hYAfU

Meta asked me for permission to use my posts to train their AI, with the option to opt out. That's because I was in Italy when I opened my account. Outside the EU you CANNOT opt out and Meta will effectively steal your memories to feed their LLMs. In those moments I think: Thank God I'm European.

Introducing our resource theory of microscopicity: a unifying framework where macroscopic entropy meets Bayesian retrodiction, Petz recovery maps, quantum coherence, athermality, etc. Everything can be understood as "inferential asymmetry" or "irretrodictability". arxiv.org/abs/2504.12738

Does anyone have a PDF of this reference? R.S. Ingarden, H. Janyszek, A. Kossakowski and T. Kawaguchi, “Information geometry of quantum statistical systems,” Tensor (N.S.) 37 (1982), pp. 105- 111. Looks like a paper that people cite but google and google scholar don't lead to a PDF

I'll say it again: federatable does not mean federated. Bluesky is by design (a central, non-bypassable node) required to comply with all requests, including those of a censorship nature. mas.to/@osma/114346...

This past week, I received a second stop work order on one of my grants. This now means that we can no longer spend on *two* of my major grants. Several of my group members will now graduate earlier than expected, I am looking into being a consultant for the summer, and students will do internships

18 years ago like today I left Geneva to take up the job that is still mine. Celebrating with my group, and thinking of all the amazing people I got to meet.

THIS!

Today begins my one-year term as department head. 😑 Wish me good luck... 😬

Beyond IID 13 Submission deadline has been extended to April 6! sites.google.com/view/beyondi...

QUOTE OF THE DAY Good ideas are so scarce they come back again and again in different disguise. -- Alexander Migdal.

We should all watch and meditate on this video at least once a day. www.youtube.com/watch?v=ZhuL...

Very much looking forward to reading this in detail.: "Unification of observational entropy with maximum entropy principles" by Joe Schindler, @philipp-strasberg.bsky.social, Niklas Galke, Andreas Winter, and Michael Jabbour arxiv.org/abs/2503.15612

I just found out that David Blackwell wasn't allowed to attend classes or do research at Princeton University in 1942 because of the color of his skin. This was while he was doing a postdoc at the Institute for Advanced Studies.

Today, "TeX for Gmail," an extension that let you type LaTeX formulas directly into emails sent through the Gmail web interface, stopped working. I used it all the time. Pretty frustrating.

Very interesting piece on social media and scientists on the LSE blog: "Bluesky will trap academics in the same way Twitter/X did" The author, Mark Carrigan, is a Senior Lecturer in Education at the University of Manchester. Independently of your position on this, I think it is worth reading

HISTORY OF PHYSICS In 1746, Pierre Louis Moreau de Maupertuis, Johann Bernoulli’s disciple, proposed a notion that he thought of as having universal application: the principle of least action. His proposal (fr.wikisource.org/wiki/Accord_...), based on metaphysical and religious views, 1/

This whole "you have to show gratitude" argument is typical of toxic relationships.

The trilemma thing is submitted. Hope for the best (brace for the worst). The thermo trilemma: Can efficient quantum measurements coexist with both the second and third laws of thermodynamics? We show they can’t, unless we renounce the Purification Church. Heretical measurements.

why, exactly, do we publish in journals like npj Quantum Information? Now going throughs proofs generated by them and having to make corrections to various issues introduced by them

Rule of thumb. If an abstract says "we fill this unfathomable void" instead of "gap," chances are it was LLM-generated.

I have just discovered the "Hardy–Littlewood Axioms of Collaboration" 1) It didn't matter whether what they wrote to each other was right or wrong. 2) There was no obligation to reply, or even to read, any letter one sent to the other. (continue in the thread...)

Does emergence exist? Is it a useful concept? Liam Graham argues in his new interesting book "Physics Fixes All the Facts" (link.springer.com/book/10.1007...) that we are better off abandoning "emergence". I discuss with him on my blog why. Check it out at boltzmannsbrain.blog/dialogue-wit...

#OnThisDay, 22 Feb 1943, Sophie Scholl is sentenced to death and immediately executed, alongside her brother and a friend, for distributing anti-Nazi literature at her university in Munich, Germany. #WomenInHistory #OTD #History #WomensHistory #WorldWar2 #EuropeanHistory 🗃️ 1/2

Her cellmate said her last words to her were “how can we expect righteousness to prevail when there is hardly anyone willing to give himself up individually to a righteous cause... It is such a splendid sunny day, and I have to go.” 2/2

This is not circulating enough among mathematicians 🧮 Cardiff University is threatening 1/2 of its staff in maths with compulsory redundancy, despite returning a significant surplus to the university

A random book by Umberto Eco translated in a random language (ok, not so random given that I'm in Tainan)

A random graffiti of the Pisa Leaning Tower, surrounded by Taipei 101 and Giza's Pyramids. The representation is not to scale.

It seems that the arXiv quant-ph has changed their policy so that it takes anywhere from 0 to 3 days for a new submission to be approved and posted. This makes it virtually impossible to know in advance when your paper will appear. Which I think it's good: Tuesdays and Fridays were really crowded

Nature hiding their reservations about the latest Microsoft paper in the review file: "The editorial team wishes to point out that the results in this manuscript do not represent evidence for the presence of Majorana zero modes in the reported devices." worked really well, see the NYT article:

I'm all set to head out for Tainan for a meeting with a long name: "2025 International Young Researchers Forum on Quantum Information Science" phys.ncts.ntu.edu.tw/act/actnews/... Expect some random posts about random stuff in the next few days.

If the public Swiss technical university EPFL in Lausanne has its own Mastodon server (actu.epfl.ch/news/the-epf...), our quantum community can have one too, right?