Anthropic Claude Mythos 5 autonomously redesigns 8 quantum circuits in 53 hours, 17x fewer gates on elliptic-curve task

On October 16, Anthropic with Harvard University and QuEra Computing published an arXiv paper announcing that its latest model Claude Mythos 5 autonomously designed 8 foundational quantum circuits within 53 hours in an automated propose-and-test loop, covering chemistry simulation, physics simulation, optimization, cryptography, and numerical computing. The research was conducted through Anthropic's STEM Fellows Program; first author is STEM Fellow Andi Gu, mentored by Anthropic quantum physicist Alek Kemeny.

In elliptic-curve point addition — a key step in quantum algorithms for solving the discrete logarithm problem — Claude Mythos 5 produced the first reversible divsteps quantum implementation in history that does not require storing branch history. The model derived new algebraic identities from mathematical theory, formally verified through the Lean proof system. One of its designs reduced quantum gate count to 1/17 of the previous best design with only 12% more qubits.

On the second highlight, the decoder for the DQI optimization algorithm, the model replaced Google's earlier extended Euclidean algorithm with the Berlekamp-Massey algorithm and, through 403 million simulated decodings, compressed the storage reservation from 665 qubits to 19 qubits, reducing gate count by about 12x compared with Google's earlier design.

The researchers also acknowledged limitations: the model initially double-checked already validated results and leaned toward familiar methods. They mitigated this by requiring several parallel approaches and periodically expanding the search. The circuits remain software implementations verified on classical computers; the work has not yet undergone independent peer review. The paper was submitted to arXiv on October 15.