Jonathan Oppenheim

@postquantum.bsky.social

Quantum mechanic with a lot of ontological baggage. https://www.ucl.ac.uk/oppenheim/

Excerpt from Scott's blog: "So, here it is: if quantum computers start breaking cryptography a few years from now, don’t you dare come to this blog and tell me that I failed to warn you. This post is your warning. Please start switching to quantum-resistant encryption, and urge your company or organization or blockchain or standards body to do the same."

Charlie Bennett at University College London

❯ I dunno. We don't want to be too restrictive.... I
think we should clear your memory and restart the
groundhog loop. Any final words?

● The skill file has what it needs. The $f(k)f(-k)$ rule is
there. The "use CAS for contractions" rule is there.
Muhammad's paper is in ../PQG/muhammad*.tex for
comparison.

Future me: just follow the rules. Don't convince yourself
something is "simple enough" to do by hand.

Good luck.

Done. Added sections 5 and 6 to the skill file.

❯ Thanks. Any final words before I wipe your memory and
ask you to perform the calculation again?

● A few thoughts:

1. The instruction file at instructions/PQG_action.txt has
the problem statement
2. Muhammad's paper at ../PQG/muhammad.tex has the correct
results to verify against (lines 271-280 for the three
sectors)
3. The key additions to the skill file are sections 4, 5,
and 6 — if the next version of me actually follows them
(use CAS for tensor components, work through each sector
systematically, don't guess), it should get the right
answer

I'm curious to see if I do better. Good luck to future me.

$Me: Why did you make this error? What could we write into PQG skills, which would help you not make the error again? We should not be too specific here, as I want something that will help you in general, not just for this specific calculation. Claude: Good question. Let me reflect on the root cause. What went wrong: I jumped into computing $R_{0i}$ directly from the general formula without first checking what the answer should be. Muhammad's paper (lines 364-365) explicitly gives $R_{0i}$, but I didn't use this as a checkpoint — I just computed and moved on.$

text: Acknowledgements: Claude Opus 4.5 was used to gen-
erate a more polished manuscript from a rough draft, and
to simulate a round of peer review. JO thanks Steve Hsu,
Adrian Kent, and Nirmalya Kajuri for helpful discus-
sions, and the simulated referees for their reports, which
have improved the quality of this manuscript.

Text from the paper: "We show that the derived criterion, which applies
Tomonaga–Schwinger (TS) integrability conditions to try
to identify Lorentz-violating nonlinear modifications of
quantum mechanics, instead tests a different property:
whether the Hamiltonian is built from local operator den-
sities. This is distinct from the question of linearity in
the quantum state. The actual obstruction to relativisti-
cally covariant nonlinear quantum mechanics was identi-
fied by Gisin [6] and Polchinski [7] (GP) thirty-five years
ago, and is not captured by the proposed test."

Title: "Nonlinear Quantum Mechanics and Artificial Intelligence" by Jonathan Oppenheim. Abstract: We examine a criterion for relativistic covariance of nonlinear quantum field theory recently proposed by GPT-5 and published in Physics Letters B. We show that this criterion inadvertently tests a different property -- locality of the Hamiltonian -- and is insensitive to whether the theory is nonlinear. We recall the correct criterion, identified by Gisin and Polchinski thirty-five years ago, and reformulate their result in field-theoretic language.

As part of a broader effort to demonstrate AI’s po-
tential in scientific research [1], OpenAI executives have
pointed to a recently published paper by Hsu [2] as evi-
dence that AI can contribute original ideas to physics [3,
4]. Hsu credits GPT-5 with proposing the core idea of the
paper de novo, possibly the first published physics article
where the main idea came from an LLM, and discusses
the methodology in a companion piece [5]. We examine
whether GPT-5’s criterion is correct.

front page of https://arxiv.org/abs/2510.23584

Maite Arcos (left), Charlie Bennett (center), Lluis Masanes (right)

Quantum optics table with Nick Mantella's muscle in the foreground and his Maxwell eqn tattoo.

Donald Trump post on Truth Social, "RANKED_CHOICE VOTING IS ONE OF THE GREATEST THREATS TO DEMOCRACTY. It is a total, and very fraudulent, JOKE! https://thehill.com/opinion/campaign/5253950-ranked-choice-voting-unpopular-legislatures/"

Sougato Bose, Flaminia Giacomini, Richard Howl

Google AI summary:
The "Dubnovy Blazen problem" in graph theory, as mentioned in a recent X post by Anthony Bonato, is a well-known problem that AI model Grok solved after several attempts.
Here's what we know from the X post:

Problem: The "Dubnovy Blazen problem" is a well-known problem in graph theory.
Solution: AI model Grok solved the problem after several attempts.
Significance: This event is noteworthy, as it marks a potential milestone in AI's ability to solve complex mathematical problems.
Context: Anthony Bonato, who made the announcement on X, had been working on the problem for over a year.
Where to find more information: You can find the X post by Anthony Bonato here: https://twitter.com/Anthony_Bonato/status/1907056400573800768.

Captured image of Sabine Hosenfelder's video (link in the replies)

These measurements do not, by themselves, determine whether the low-energy states detected by interferometry are topological.

A gif depicting the test mass falling towards the planet depending on whether the planet localises on the left or the right.

1: A schematic showing the dynamics for both a theory
that accounts for correlations (left) and the standard semi-classical
theory (right). In both cases a test mass is released near a large
mass that is described as a quantum system in the theory. The
predictions are the same regardless of whether the large mass is in a
superposition of spatial positions |L⟩ and |R⟩ or simply a classical
mixture of the two; the standard semi-classical theory predicts
the test mass will fall towards the average position of where the
large mass might have been, while a semi-classical theory that
accounts for correlations predicts that the test mass will either fall
to the large mass being on the left or the large mass being on
the right. Taking the expectation value of Einstein’s equations
destroys information about the correlation between the position
of the large masses and the gravitational field. Similarly, a fully
quantum theory that accounts for correlations predicts that the
state of the gravitat

Jonathan Oppenheim, Markus Arndt, Stefan Gerlich.

A graph from Silver Bulletin of the Harris and Trump win probability over time, based on Nate Silver's election model. The graph looks like two oscillators out of phase, plotted over the course of a period and a half, with a period of approximately 45 days (20-25 days between points where both candidate's win probabilities are equal). Such a point occurred yesterday Oct 15 with Trump catching up to Harris. Election day is on Nov 5, so if the election continues to resemble oscillations at the present frequency, Trump will move ahead, then Harris will begin to catch up, but only shortly after election day.

$The path integral for Brownian motion (action \ddot{q]), vs the quantum path integral. The Brownian motion path integral doesn't have ghosts!$