Anthropic Says Claude Computed a Nine-Loop Particle Physics Amplitude

Summary

AI Models & Platforms Anthropic Says Claude Computed a Nine-Loop Particle Physics Amplitude Add Unite.AI to your preferred sources on Google Anthropic on September 25, 2026 published a guest post on its research site reporting that two of its physicists used the company’s Claude model to compute the six-particle scattering amplitude in planar N=4 super Yang-Mills at nine loops, answering a public challenge issued to AI companies on August 7, 2026. The Challenge Matt von Hippel, a former theoretical physicist who now writes about physics at 4gravitons.com, set the terms in an August 7, 2026 blog post. He asked AI companies to show that an AI, using the computing resources an academic has access to, could solve one of the scattering amplitudes field’s big outstanding problems: determining whether N=8 supergravity diverges at seven loops, or finding the six-particle amplitude in N=4 super Yang-Mills at nine loops. “Give us N=8 supergravity to seven loops, or N=4 super Yang-Mills to nine loops,” he wrote. Von Hippel argued that these problems are hard in a computational sense: each loop represents an increase in complexity, in calculations that typically scale exponentially or even factorially in the number of loops. In principle, he wrote, amplitudes researchers could solve any of them with no new ideas, using known methods, but they would need access to far more computing power. At the end of August 2026, Liam Fitzpatrick and Siddharth Mishra-Sharma, two physicists at Anthropic, contacted von Hippel to say they had tackled one of the challenges, and after verifying the result with longtime amplitudes researcher Lance Dixon they walked him through the work. The post’s disclosure states that Anthropic invited von Hippel to write the guest post and compensated him for his time, that Anthropic staff gave feedback on drafts, and that the content and opinions are his own. The Physics Problem Scattering amplitudes are formulas that let physicists use the momenta and energies of subatomic particles to calculate how likely they are to react in particular ways. They are hard enough to compute that physicists almost always work with approximations cut off at a specific number of loops: the more loops included, the closer the result comes to the real answer and the harder the calculation becomes. Most scattering amplitude formulas have been calculated only to two loops,…