Anthropic says Claude cracked a nine‑loop physics problem
Claude spent about a week computing a particle-physics calculation past the previous eight-loop record, and Stanford physicist Lance Dixon, who set that record, verified the result.
Anthropic said its Claude Science system computed a nine-loop scattering-amplitude calculation in theoretical particle physics. That is one loop past the previous record of eight, set by Stanford's Lance Dixon and collaborators. Dixon independently verified Claude's result, Anthropic said, after physicist and science writer Matthew von Hippel challenged AI companies last month to attempt the problem.
https://x.com/AnthropicAI/status/2103541577083719888
Anthropic researchers Liam Fitzpatrick and Siddharth Mishra-Sharma gave Claude a single prompt describing the six-particle amplitude. They told it to keep working with updates every four to six hours, the company said. Claude ran largely unsupervised for about a week on 96 parallel CPUs. It solved the problem with two methods: a bootstrap approach and a separate form-factor technique.
The full computation cost a few thousand dollars, Anthropic said, with the bootstrap method alone costing about $100. Within days of Anthropic's result, a group led by Song He at the Chinese Academy of Sciences reported similar progress. It said it had computed parts of the same nine-loop result using GPT-6 alongside human researchers.
Von Hippel wrote that Claude relied on established methods rather than inventing new ones. That, he said, suggests "there is more low-hanging fruit out there than you'd expect." Claude also reached the correct answer in a single attempt, he noted, where such calculations typically demand several rounds of debugging.