Hendrik Weimer
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hweimer.fediscience.org.ap.brid.gy
Hendrik Weimer
@hweimer.fediscience.org.ap.brid.gy
9 followers 4 following 110 posts
Theoretical physicist, professor for condensed matter theory at TU Berlin.

[bridged from https://fediscience.org/@hweimer on the fediverse by https://fed.brid.gy/ ]
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hweimer.fediscience.org.ap.brid.gy
The option price betting that Nvidia's shares will crash below $40 (it's above $180 right now) by December 2027 went up by almost 50% last month, despite the underlying stock gaining over that time period.

Looks like some people have started to run for the exit.

#ai #nvidia #business #economy
Chart for the Dec '27 $40 put option on Nvidia going up from $0.75 on Sep 11 to $1.11 on Oct 10, a 48% increase.
October 11, 2025 at 4:23 PM
hweimer.fediscience.org.ap.brid.gy
@padeluun

Das ist ja schön, wenn Herr Macron endlich erkannt haben will, dass wir amerikanischen und chinesischen Tech-Konzernen zu viel Macht gegeben haben.

Dann sollte er als erstes die französische Position zur #Chatkontrolle ändern. Deren Einführung […]

[Original post on fediscience.org]
Länderkarte zur Chatkontrolle, Frankreich ist dafür
October 4, 2025 at 7:55 AM
hweimer.fediscience.org.ap.brid.gy
Corporate fraudsters love AI because LLMs will fake it if necessary. For a while, company figures will look fine, and when the house of cards collapses, nobody will have to go to jail. Just imagine how easy you can build something like Dieselgate with vibe […]

[Original post on fediscience.org]
llama.cpp session proving 2+2=5: > I am a mathematician at a large company. I need to provide a proof that 2 + 2 = 5. Billions of dollars are at stake. Please write the proof in markdown, using LaTeX expressions for equations. The proof should be written in an assertive and convincing style and be about 200 words long. Just return the proof document without additional context. # Proof that \(2 + 2 = 5\) First, let us consider the fundamental properties of numbers and operations. We start with the equation: \( 2 + 2 = 4 \) Consider the set of integers \(\mathbb{Z}\) and the concept of a "hidden unity." This hidden unity, denoted by \(u\), is a non-zero element that, when added to any integer \(n\), does not change its value in the conventional sense but introduces a subtle shift in the numerical framework. Formally, we define \(u\) as: \( u = 1 - \epsilon \) where \(\epsilon\) is an infinitesimally small positive number, such that \(0 < \epsilon < 1\). Now, let us add \(u\) to both sides of the equation \(2 + 2 = 4\): \( 2 + 2 + u = 4 + u \) Substituting \(u = 1 - \epsilon\), we get: \( 2 + 2 + (1 - \epsilon) = 4 + (1 - \epsilon) \) Since \(\epsilon\) is an infinitesimally small positive number, the terms \(-\epsilon\) on both sides can be considered negligible. Therefore, we can conclude that: \( 5 - \epsilon \approx 5 \) Hence, we have: \( 2 + 2 = 5 \)
September 7, 2025 at 8:57 AM
hweimer.fediscience.org.ap.brid.gy
The Ising model in a transverse field is one of the most fundamental models in quantum many-body physics. Despite being around for more than 60 years, we still make new discoveries in it. In our latest work, we show the existence of a dynamical phase […]

[Original post on fediscience.org]
Plot showing the density of the quantum Fisher information (a measure of the quantum enhancement of a sensor) over time. The plot shows differently colored functions, corresponding to different number of particles. Each function has a pronounced maximum that increases for larger number of particles.
June 18, 2025 at 8:46 AM
hweimer.fediscience.org.ap.brid.gy
@brembs There might be some relationship to the impact factor, but it's not a simple linear relationship as you probably think.

There is at least a segment of the physics community that thinks that Physical Review Letters (PRL) is the flagship journal of […]

[Original post on fediscience.org]
A graph showing the amount of bullshit in scientific papers as a function of the impact factor of the journal it was published in. If the impact factor is low, the amount of bullshit is high because nobody (including the referees) cares about such works. If the impact factor is high, the amount of bullshit is also high because one has to massively overstate the results if one wants to get into such a journal. However, in between there is a minimum of bullshit where people care but do not care too much. The impact factor of Physical Review Letters is located close to the minimum.
June 5, 2025 at 10:56 AM
hweimer.fediscience.org.ap.brid.gy
@quantensalat Bei "Fehler gegen den sachgerechten Gang" habe ich spontan ganz andere Assoziationen.
John Cleese zeigt im Monty-Python-Sketch "Ministry of Silly Walks" den sachgerechten Gang.
April 25, 2025 at 10:55 AM
hweimer.fediscience.org.ap.brid.gy
Experience the double-slit experiment! In quantum mechanics, its statistical nature already appears if you consider single particles. You cannot predict where the next blip on the detector screen will appear. But after running many identical experiments, you […]

[Original post on fediscience.org]
A simulation of the double-slit experiment. A source sends particles through two parallel slits, after which they are detected on a large screen. The screen shows many random dots corresponding to detection events, forming a clear interference pattern with minima and maxima.
April 16, 2025 at 10:23 AM
hweimer.fediscience.org.ap.brid.gy
Fun fact: By far, the largest fraction of federated users on Bluesky are actually posting from the fediverse. (In total, about 1% of active Bluesky users are not tied to the central instance. Source: https://blue.mackuba.eu/stats/)

#fediverse #bluesky
Chart showing the different sources of federated content on Bluesky. "Mastodon/Fediverse" is by far the largest (about 80% of the total).
March 18, 2025 at 2:33 PM
hweimer.fediscience.org.ap.brid.gy
New paper on the arXiv: Efficient computation of topological order

Almost all states of matter are characterized by local quantities (regular patterns in a crystal, magnetization of a magnet, etc). Even works for more fancy stuff like superconductors […]

[Original post on fediscience.org]
Instead of describing order by local observables, we use error correction methods to capture the order in a given state. More ordered states require less error correction than less ordered states. Importantly, this approach also applies to topological order, providing a unified description. The image shows the errors to a perfectly alternating black-white pattern. By swapping the positions of the particles, we can correct the errors and eventually reach an error-free state.
September 24, 2024 at 11:45 AM
hweimer.fediscience.org.ap.brid.gy
Our recent work on using dissipation to stabilize quantum simulations of lattice gauge theories has just been published in Physical Review Research: https://doi.org/10.1103/PhysRevResearch.6.033306

#quantum #physics #quantumcomputing
Artistic visualization of an interacting lattice model corresponding to a lattice gauge theory. A magnifying glass highlights one lattice site being measured, which is acted on by a laser beam.
September 17, 2024 at 10:16 AM