In a research post published October 16, Anthropic reported that its Claude Mythos 5 model, working in a closed loop with an automated evaluator and largely without human input between rounds, designed quantum circuits that improve on the best previously published designs across eight computational primitives spanning chemistry, optimization, quantum simulation, number theory and numerical computing.

On seven of the eight tasks the discovered circuits significantly reduced both Toffoli gate counts and qubit counts versus the prior state of the art; the eighth produced a new reversible architecture for prime-field modular inversion. In one elliptic-curve case a circuit used 12% more qubits but 17 times fewer gates, from a single 53-hour run, and on a decoded quantum interferometry decoder Claude cut the gate count by a factor of 12 versus Google's previous construction while trimming memory from 665 to 19 qubits.

The work was led by Andi Gu under Anthropic's STEM Fellows Program, mentored by Anthropic quantum physicist Alek Kemeny and done with Harvard's Susanne Yelin and Mikhail Lukin, also of QuEra Computing. A 46-page companion paper was submitted to arXiv on October 15. The results are Anthropic's own, produced inside its evaluator-driven setup, and await outside replication.