# Claude sets a physics record: what happened and why it matters

> Anthropic says Claude computed a record nine-loop physics calculation, largely unsupervised.

*A quick look at Anthropic's nine-loop scattering amplitude claim.*

By The FeaturedDaily Desk · FeaturedDaily
Canonical: https://featureddaily.com/news/claude-physics-record-briefing

**What happened:** Anthropic said on 25 September that its Claude AI model computed the nine-loop six-particle scattering amplitude in a physics theory called planar N=4 super-Yang-Mills, beating the previous eight-loop record set in 2023 by physicists Lance Dixon and Andy Liu.

**The background:** Scattering amplitudes predict how particles behave; extra "loops" add precision but make the maths far harder. The theory used, N=4 super-Yang-Mills, is a simplified physics testbed, not a model of real particles.

**How it happened:** Claude answered a public challenge posted on 7 August by physics writer Matt von Hippel. Anthropic physicists Liam Fitzpatrick and Siddharth Mishra-Sharma gave the model, running as Fable 5.1 inside Claude Science, one instruction and let it work largely alone from there.

**The effort:** Claude completed the calculation two separate ways, taking about a week on 96 CPUs, at a cost of roughly $1,000 to $2,000 per method, [Anthropic said](https://www.anthropic.com/research/yes-claude-can-do-nine-loops).

**The validation:** SLAC physicist Lance Dixon spent about two weeks independently checking the result. A separate Beijing team led by Song He reached most of the same result around the same time, using GPT-6-based AI assistance for some constraints.

**The endorsement:** Dixon praised the model's ability to carry out every step of the complex calculation method involved, calling the achievement a genuine triumph for a large language model.

**Why it matters:** the result adds to a run of high-profile claims from AI labs about models tackling frontier science problems, and doubles as validation for Claude Science, Anthropic's push into research tools.

**The caveat:** Anthropic was clear this isn't new physics — Claude executed a known calculation recipe on an unusually hard problem, rather than discovering something new about how particles behave.

**The scale:** the previous eight-loop record, set by Lance Dixon and Andy Liu in 2023, had stood for about three years before Claude's nine-loop result surpassed it.

**Independent check:** a Beijing-based team's parallel effort, reaching a similar answer using different AI assistance, adds further confidence that the nine-loop result itself is correct.

**What's next:** Anthropic did not say whether it plans a ten-loop attempt, describing the result instead as a demonstration of Claude working largely unsupervised on a hard, well-defined task.

**The cost:** Anthropic put the bill at roughly $1,000 to $2,000 per method, for about a week of computing on 96 CPUs, a small outlay for a record that no human team had reached by direct calculation.

**The origin story:** von Hippel put the nine-loop problem to AI companies in general as a public challenge, and Anthropic's own team chose to take it on.

**The trust angle:** an independently checked result, largely matched by a separate Beijing-based team, is harder to dismiss than a typical internal AI benchmark score alone.

## Key takeaways

- Claude computed a nine-loop scattering amplitude, beating the 2023 eight-loop record.
- It worked largely unsupervised for about a week on 96 CPUs, costing $1,000-$2,000 per method.
- A SLAC physicist independently verified the result; Anthropic says it is not new physics.

## Sources

- [Yes, Claude can do nine loops](https://www.anthropic.com/research/yes-claude-can-do-nine-loops) — Anthropic, 2026-09-25