What comes to my mind. Physics, politics, computers, rants. All CC-BY-SA unless otherwise stated.
Recently I had to update Mathematica on my laptop and after having solved the challenges of the license manager that keeps looking different every time I have to use it, I learned that Mathematica 14 can now officially work with finite fields. This reminded me that for a while I wanted to revive an old project that had vanished together with the hard drive of some old computer: Holosplit. So, over…
I had this neat calculation in my drawer and on the occasion of quantum mechanic's 100th birthday in 2025, I decided I submit a talk about it to the March meeting of the DPG, the German physical society, in Göttingen. And to have to show something, I put it out on the arxiv today. The idea is as follows: The GHZ experiment is a beautiful version of Bell's inequality that demonstrates you get to…
Once more, I am trying to better understand the Bohmian or pilot wave approach to quantum mechanics. And I came across this technical question, which I have not been able to successfully answer from the literature: Consider a particle, described by a wave function \(\psi(x)\) and a Bohmian position \(q\) that both happily evolve in time according to the Schrödinger equation and the Bohmian…
I came across this excerpt from a a christian home schooling book: which is of course funny in so many ways not at least as the whole process of "seeing" is electromagnetic at its very core and of course most people will have felt electricity at some point in their life. Even historically, this is pretty much how it was discovered by Galvani (using forge' legs) at a time when electricity was about…
You might have heard about recent efforts to inspect lots of "wide binaries", double stars that orbit each other at very large distances, which is one of the tasks the Gaia mission was built for, to determine if their dynamics follows Newtonian gravity or rather MOND, the modified Newtonian dynamics (Einstein theory plays no role at such weak fields). You can learn about the latest update from…
Here is a little puzzle I just came up with when in today's hep-th serving I found arXiv:2304.14351 [ pdf , other ] Operator growth and black hole formation Felix M. Haehl , Ying Zhao Comments: 20+9 pages, 10 figures. arXiv admin note: text overlap with arXiv:2104.02736 Subjects: High Energy Physics - Theory (hep-th) ; General Relativity and Quantum Cosmology (gr-qc); Quantum Physics (quant-ph)…
I wrote a text as a comment on the episode of the Logbuch Netzpolitik podcast on the FTX debacle but could not post it to the comment section (because that appears to be disabled). So in order not to waste I post it here (in German): 1. Hebel (leverage): Wenn ich etwa glaube, dass in Zukunft die Appleaktie weiter steigen wird, kann ich mir eine Appleaktie kaufen, um davon zu profitieren. Die…
On the occasion of the a nnouncement of the Nobel prize for Aspect, Clauser and Zeilinger for the experimental verification that quantum theory violates Bell's inequality, there seems to be a strong urge in popular explanations to state that this proves that quantum theory is non-local, that entanglement is somehow a strong bond between quantum systems and people quote Einstein on the "spooky…
The latest addition to our single chip computer zoo is Adafruit's Circuit Playground Express . It is sold for about 30$ and comes with a lot of GIO pins, 10 RGB LEDs, a small speaker, lots of sensors (including acceleration, temperature, IR,...) and 1.5MB of flash rom. The excuse for buying it is that I might interest the kids in it (being better equipped on board than an Arduino while being less…
Over the last few days, I have been involved in some heated Twitter discussions around a possible reform of the voting system for the German parliament. Those have sharpened my understanding of one or two things and that's why I think it's worthwhile writing a blog post about it. The root of the problem is that the system currently in use tries to optimise two goals which are not necessarily…
Since a few days, I am following the hype and play wordle . I think I got lucky the first days but I had already put in some strategy as in starting with words where the possible results are most telling. I was thinking that getting the vowels right early is a good idea so I tend to start with "HOUSE" (continuing three vowels and an S) possibly followed by "FAINT" (containing the remaining vowels…
I am an old man. I am convinced email a superior medium for person to person information exchange. It is text based, so you don't need special hardware to use it, it can still transport various media formats and it is inter-operational, you are not tied to one company offering a service but thanks to a long list of RFCs starting with number 822 everybody can run their own service. Via GPG or…
This is a follow-up to a Twitter discussion with John Baez that did not fit into the 260 character limit. And before starting, I should warn you that I have never studied set theory in any seriousness and everything I am about to write here is only based on hearsay and is probably wrong. I am currently teaching "Mathematical Statistical Physics" once more, large part of which is to explain the…
I really enjoyed last week's Zoom edition of the annual Strings conference. Clifford has said many of the things about it that I support wholeheartedly, so I don't have to repeat them here. One of the things I really liked was the active participation in the chat channel that accompanied the talks. But some of the things I read there gave me the impression that there is some confusion out there…
You might have come across news about a search engine for faces: https://pimeyes.com/en/ . You can upload your photo and it will tell you where in the interwebs it has seen you before. Of course, I had to try it. Here are my results: OK, that was to be expected. This is the image I use whenever somebody asks me for a short bio with a picture or which I often use as avatar. This is also the first…
Seit heute gibt es sie, die Corona-Warn-App , und ihr könnt (und solltet, siehe unten) sie herunterladen und installieren. Das ist die kurze Nachricht. Sie hätte auch in einen Tweet gepasst. Warum noch ein Blogpost? Das liegt daran, dass viele Bedenken gegen diese App kursieren und andererseits niemand (insbesondere nicht der CCC) sagt "Alles Quatsch, die App ist sicher!". Diese Situation würde…
In the last few days, there was news that several big academic high performance computing centers had been hacked. Here in Munich, LRZ, the Leibniz Rechenzentrum was affected but apparently also computers at the LMU faculty of physics (there are a few clusters in the institute's basement). You could hear that it were Linux systems that were compromised and the attackers left files in /etc/fonts. I…
I write this post because I am genuinely interested in people's opinions. So please comment even if usually you wouldn't and it's ok to to simply say you agree with somebody's opinion (or not). And of course you can do this anonymously or under a pseudonym. The question is: What is the right balance between participants privacy and making things public in the name of public knowledge? Let me…
Florian Freistetter has posed the challenge in his blog to write a generally accessible text on why nuclear fusion works. Here is my attempt (according to the rules in German): Gleich und gleich gesellt sich gern Wassertropfen auf einer Oberfläche, Fettaugen in der Suppe, Bläschen in der Limo (oder im Körper eines Tauchers, siehe mein anderes Blog ) und eben Atomkerne, diese Phänomene haben…
The year 2019 is the International Year of the Periodic Table celebrating the 150th anniversary of Mendeleev's discovery. This prompts me to report on something that I learned in recent years when co-teaching "Mathematical Quantum Mechanics" with mathematicians in particular with Heinz Siedentop : We know less about the mathematics of the periodic table) than I thought. In high school chemistry…
Sorry, this one of the occasional posts about German politics and thus in German. This is my posting to a German speaking mailing lists discussing the upcoming EU copyright directive (must be stopped in current from!!! March 23rd international protest day) and now the CDU party has proposed how to implement it in German law, although so unspecific that all the problematic details are left out.…
Further down the rabbit hole, over lunch I finished watching "Behind the Curve" , a Netflix documentary on people believing the earth is a flat disk. According to them, the north pole is in the center, while Antarctica is an ice wall at the boundary. Sun and moon are much closer and flying above this disk while the stars are on some huge dome like in a planetarium. NASA is a fake agency promoting…
Visits to a Bohmian village Over all of my physics life, I have been under the local influence of some Gaul villages that have ideas about physics that are not 100% aligned with the main stream views: When I was a student in Hamburg, I was good friends with people working on algebraic quantum field theory. Of course there were opinions that they were the only people seriously working on QFT as…
Today, there was news about a huge database containing 773 million email address / password pairs became public. On Have I Been Pawned you can check if any of your email addresses is in this database (or any similar one). I bet it is (mine are). These lists are very probably the source for the spam emails that have been around for a number of months where the spammer claims they broke into your…
I am a bit late for the party, but also wanted to share my two cents on the paper "Quantum theory cannot consistently describe the use of itself" by Frauchiger and Renner. After sitting down and working out the math for myself, I found that the analysis in this paper and the blogpost by Scot (including many of the the 160+ comments, some by Renner) share a lot with what I am about to say but maybe…