Anthropic Says Claude Beat Best Published Quantum Circuit Designs

In a research post published October 16, 2026, Anthropic reported that its Claude Mythos 5 model, working in a closed loop with an automated evaluator and largely on its own, designed quantum circuits that improve on the best previously published circuits across eight computational primitives, in some cases by an order of magnitude or more. The primitives, the basic routines from which larger quantum algorithms are built, span chemistry, optimization, quantum simulation, number theory, and numerical computing.

Andi Gu led the work as part of Anthropic’s STEM Fellows Program, with mentorship from Alek Kemeny, a quantum physicist at Anthropic, and in collaboration with Susanne Yelin of Harvard University and Mikhail Lukin of Harvard University and QuEra Computing. A companion paper, Discovering state-of-the-art quantum circuits with large language models, was submitted to arXiv on October 15, 2026 by Gu, Kemeny, Yelin, and Lukin and runs 46 pages with 10 figures and six tables.

The abstract describes an evolutionary framework in which large language models propose circuit designs and an independent evaluator verifies and scores them. It states that in seven of…