Jonathan Oppenheim

The path-integral formulation of the Postquantum theory of classical gravity is now in Physical Review X! Other results from our group have been published at the same time, so this is a good opportunity to review progress. ⚛️ 🧪https://superposer.substack.com/p/postquantum-gravity-new-results-and 1/2

We invite applications for Research Fellow positions as part of a new initiative to be launched in late 2026 at the interface of quantum information theory and gravity! Please RT and let potentially interested researchers know. www.ucl.ac.uk/mathematical... 1/2

Congratulations to Charlie Bennett and Gilles Brassard for winning the 2026 Turing Award (akin to the Nobel Prize for Computer Science)! They invented quantum cryptography and quantum teleportation. awards.acm.org/turing 🧪 ⚛️ 1/

Charlie in particular was responsible for our modern understanding of entanglement (as a resource) and was a founder of the field of quantum information theory. He also used information theory to exorcise Maxwell's demon (the demon's brain has to be reset like a memory tape and this costs work). 2/

"Good luck to future me." That was Claude's farewell before I wiped its memory for the fourth time. I finally got an AI to do a research-level physics calculation correctly via a Groundhog Day loop. Details below and in my post: superposer.substack.com/p/teaching-a... ⚛️🧪🧵 1/7

After several rounds, the skill file contained hard-won wisdom from iterations it couldn't remember. Fresh Claude, no memory of any of this, reads the skill file, does the calculation. Five minutes. Right answer. 6/

"Good luck to future me." That was Claude's farewell before I wiped its memory for the fourth time. I finally got an AI to do a research-level physics calculation correctly via a Groundhog Day loop. Details below and in my post: superposer.substack.com/p/teaching-a... ⚛️🧪🧵 1/7

We eventually distilled some actual lessons which were more generally applicable, then came the loop. Add lessons to the SKILL file → flashy-thing its memory, Men in Black style 🕶️ → retry the calculation → reflect and update the SKILL file→ wipe →repeat. 4/

"Good luck to future me." That was Claude's farewell before I wiped its memory for the fourth time. I finally got an AI to do a research-level physics calculation correctly via a Groundhog Day loop. Details below and in my post: superposer.substack.com/p/teaching-a... ⚛️🧪🧵 1/7

First attempt: Claude did a calculation in 5 minutes. My student Muhammad took a week. Remarkable speed. Wrong answer. But Claude Code lets you teach the model via SKILL files—instructions that persist across sessions. 2/

OpenAI leadership are promoting a paper in Physics Letters B where GPT-5 proposed the main idea — possibly the first peer-reviewed paper where an LLM generated the core contribution. One small problem: GPT-5's idea tests the wrong thing. My technical comment: scirate.com/arxiv/2512.0... 1/

It was accepted (with revisions)😀. I've updated my blog post on Science Slop superposer.substack.com/p/we-are-in-... 6/6

OpenAI leadership are promoting a paper in Physics Letters B where GPT-5 proposed the main idea — possibly the first peer-reviewed paper where an LLM generated the core contribution. One small problem: GPT-5's idea tests the wrong thing. My technical comment: scirate.com/arxiv/2512.0... 1/

To his credit, the author of the paper is transparent about his use of LLMs, has written thoughtfully about how to verify them, and is clear that it is the user who must take responsibility for the paper. x.com/hsu_steve/st... 4/

OpenAI leadership are promoting a paper in Physics Letters B where GPT-5 proposed the main idea — possibly the first peer-reviewed paper where an LLM generated the core contribution. One small problem: GPT-5's idea tests the wrong thing. My technical comment: scirate.com/arxiv/2512.0... 1/

GPT-5 was asked for a test that detects nonlinear theories. It provided a test that detects nonlocal ones. Related-sounding, but different. It's like asking for a COVID test, and the LLM cheerfully hands you a test for chickenpox. Same neighbourhood different house. 2/

A recent @nature.com article claims that classical (unquantised) gravity produces entanglement. We show that their model does not produce entanglement. Even if the model produced entanglement, it would be mediated by the quantised matter interaction, and not gravity. scirate.com/arxiv/2511.0... 🧪⚛️

Another day, another arxiv paper claiming that classical gravity can produce entanglement. Last week's Nature paper continues to cause confusion. But classical fields can't create entanglement *even if* they directly couple two masses. Comment added at superposer.substack.com/p/no-classic...

No they do not. I'll try to write something up in the next few days....

What if the measurement problem isn't about explaining how the classical world emerges from the quantum world... ...but about what happens when quantum systems interact with something that's already classical? Turns out, the collapse postulate + Born rule emerge! scirate.com/arxiv/2510.0... 🧪⚛️🧵1/5

Now here's the remarkable part: we just apply standard classical probability theory to the classical system. Using a change of measure (standard tool from finance/probability), and the Born rule ( |ψ|²)emerges automatically. No measurement postulate needed. No many worlds. 4/5

What if the measurement problem isn't about explaining how the classical world emerges from the quantum world... ...but about what happens when quantum systems interact with something that's already classical? Turns out, the collapse postulate + Born rule emerge! scirate.com/arxiv/2510.0... 🧪⚛️🧵1/5

Joint work with Isaac Layton and Zachary Weller-Davies. We propose a few simple axioms: - A classical system exists. - Quantum systems evolve linearly. - Their interaction may be stochastic. - The interaction depends on the current quantum state. - No preferred basis. 2/5