New science blog post: Yes, Claude can complete the nine-loop calculation.

EA-Anthropic · 2026-09-27

Theoretical physicists use formulas called scattering amplitudes to predict the behavior of particles. These formulas are notoriously difficult to calculate, so researchers use a method of layer-by-layer fine corrections, called "loops"—each additional loop makes the answer more precise, but the amount of computation grows exponentially. Most calculations stop at two or three loops. In a simplified model that physicists use as a testing ground (planar N=4 super Yang-Mills theory), the previous record was eight loops, set by Lance Dixon of SLAC and his collaborators.

Last month, physicist and science writer @4gravitons issued a challenge: Can AI break through eight loops in this model, using only a computational budget that a single scholar could reasonably obtain?

With only a prompt describing the nine-loop problem, Claude ran for several days in Claude Science essentially unsupervised, using the method developed by Dixon and his colleagues to solve the problem, at a total cost of only a few thousand dollars. Dixon independently verified the result, and von Hippel wrote about this experience for our blog.