Claude Solves Nine-Loop Physics Problem for ~$2,000, Breaking Three-Year Record

智东西 · wechat · 2026-09-26

Anthropic says Claude, running for days at a cost of roughly $1,000–2,000, completed the nine-loop calculation in N=4 super Yang-Mills theory almost entirely unsupervised—breaking the record SLAC's Lance Dixon set with an eight-loop amplitude in 2023. Dixon, who verified the result, said he had considered a direct solve nearly impossible.

The challenge came from former theoretical physicist Matt von Hippel, who dared AI labs to crack either seven-loop N=8 supergravity or nine-loop N=4 SYM. Anthropic used its Fable5.1 model on the ClaudeScience platform: researchers asked the model which problem looked most tractable, gave a single task prompt, then simply told it to keep going. Claude solved the problem via two independent routes—the traditional bootstrap method (about $100 of compute, 96 CPUs for a week) and an indirect form-factor approach—with minimal human intervention. Days after von Hippel heard from Anthropic, He Song's team at the Chinese Academy of Sciences reported getting the main result with GPT-6 assistance.

Von Hippel's verdict: Claude reused mature existing methods with more compute rather than producing genuinely new ideas—but the result confirms that the field has long undervalued low-hanging fruit that better software engineering could pick. It follows Claude's discovery last week of an unknown enzyme system hidden in phage DNA.

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Claude Solves Nine-Loop Physics Problem for ~$2,000, Breaking Three-Year Record

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