Harvard–Anthropic team (with Mikhail Lukin) uses Claude Mythos 5 in an evolutionary search to beat state-of-the-art quantum circuits on seven of eight tasks
Partly confirmed
The takeaway
An LLM-plus-evaluator search, starting from blank programs, cut Toffoli-times-qubit costs by 4× to 39× for quantum arithmetic subroutines and found a new reversible design for modular inversion.
Status
- Claim
Partly confirmed
- Our reporting
- Medium confidence
- Importance
- 3 of 5
- Last verified
- 16 October 2026
Your AI and this story
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None of these four assistants can know about it. The closest, Claude Opus 5.5, stops 107 days before it.
Key facts
- Paper: ‘Discovering state-of-the-art quantum circuits with large language models’, Andi Gu (Harvard; Anthropic STEM Fellows Program), Alek H. Kemeny (Anthropic), Susanne F. Yelin (Harvard), Mikhail D. Lukin (Harvard; QuEra), arXiv 2610.22367 [quant-ph], 15 Oct 2026
- Setup (quoted): ‘We search over these circuit-generating programs with OpenEvolve, using Claude Mythos 5 to propose architectures and program rewrites … Starting from a blank program, it chooses the algorithm, representation, and circuit structure and produces the discovered circuits without substantive human intervention’; MAP-Elites keeps Toffoli/qubit trade-offs
- Table I, Toffoli×qubit gain over baseline: Reed–Solomon DQI decoder 12× (5.1M → 440k Toffolis); HHL rotation angle 32×; Coulomb potential 9.9×; fixed-point Gaussian 39×; FeS alias–Select 4.1×; non-abelian lattice-gauge simulation 7.7×; Hermitian DQI decoder: first reversible compilation (9.3·10⁵ Toffolis vs 10⁸ naive)
- Modular inversion: a new reversible architecture that makes divsteps, a classical algorithm ‘previously impractical for reversible integer arithmetic’, viable; separately a specialised Luo construction with 3.4× fewer Toffolis at five extra qubits
- Authors’ framing: ‘some apparent costs of quantum arithmetic reflect limitations of existing reversible constructions rather than of the algorithms themselves’
What happened
Quantum algorithms often spend most of their cost on classical subroutines (arithmetic, decoding, function evaluation) that must be written as reversible circuits. Optimizers usually only apply equivalence-preserving rewrites to a fixed design.
On 15 Oct 2026 a Harvard group led by Mikhail Lukin, with an Anthropic co-author and an Anthropic STEM Fellow as first author, posted arXiv 2610.223671. Claude Mythos 5, inside OpenEvolve, proposes whole circuit-generating programs from a task specification and a blank start; a separate evaluator checks correctness on basis states and scores Toffoli count times peak qubits. Across eight tasks from optimisation, chemistry, simulation and number theory, the search beat published constructions in seven, often by an order of magnitude, for example a 12× lower cost for the Reed–Solomon decoder in decoded quantum interferometry. In the eighth it found a reversible design for the divstep modular-inversion algorithm.
No Hacker News thread was found on 16 Oct (Algolia); X was not searched.
Why it matters
Resource estimates for useful quantum algorithms depend on such subroutines; large cuts in their cost move estimates for applications like DQI and lattice-gauge simulation. It is also an AlphaEvolve-style result with a frontier commercial model and an open-source framework, by a leading experimental quantum group.
Sources
1 source from 1 site. Numbers match the chips in the text.
1 source: 1 primary
Primary
Changes
- Filed from the arXiv PDF