❯ Anthropic says Claude computed a nine-loop scattering amplitude, beating the human eight-loop record for a few thousand dollars

One loop past the recordIn a research post on September 25, Anthropic says Claude computed the six-particle scattering amplitude in planar N=4 super Yang-Mills theory at nine loops, past the eight-loop record SLAC’s Lance Dixon and collaborators set in 2023. A scattering amplitude describes the probabilities of outcomes when particles collide, and each extra “loop” makes the calculation harder. N=4 super Yang-Mills is a simplified toy theory that does not describe the real universe, so solving it does not answer questions about the physical world.

A blog challenge becomes a computationIt began when Matt von Hippel, a particle physicist turned science writer, challenged the AI community in August, on his blog, to tackle a frontier problem with academic-scale resources. Anthropic physicists Liam Fitzpatrick and Siddharth Mishra-Sharma took it up on the Claude Science platform, where Claude computed the result twice by different physical routes: the bootstrap method and an indirect form-factor approach. Anthropic puts the cost at about $1,000 to $2,000 for each method, with the bootstrap part equivalent to 96 processors running for a week. Dixon’s team verified it independently and it checked out; he said Claude used the methods he and his collaborators built over the years.

A Chinese team published firstAt almost the same time, He Song’s group at the Institute of Theoretical Physics, Chinese Academy of Sciences, released a dataset on Zenodo with the symbols of the six-gluon MHV amplitude up to nine loops, dated September 17, eight days before Anthropic’s post. According to 21st Century Business Herald, they used GPT-6 to compute some constraints while the researchers built the overall framework, unlike Anthropic’s near-fully-automated approach of a single prompt, repeatedly continued.

The hard part shifts from budget to choosingVon Hippel’s own read is that these were known methods with more compute than people had tried before, and that many seemingly out-of-reach goals may simply not have seemed worth the compute. Theoretical physicists may spend more of their effort deciding what to compute and how to verify it, and less on deriving each loop by hand.

▪ SIGNALThe record invents no new physics; it shows that some frontier problems were stuck only because nobody wanted to spend a few thousand dollars trying.