Matt Landreman; Gómez-Serrano, Liehr and Taylor · AI-Discovered Physics

Grad's Conjecture Disproved with AI Help

Two papers posted 21 and 22 September refute Grad's 1967 conjecture that magnetic plasma equilibria in a torus must have reflection, axial or helical symmetry, a question central to fusion reactor design. Matt Landreman's paper (arXiv 2609.26742) gives exact analytic 3D solutions in elementary functions, one family with uniform rotational transform and one with sheared, and his repo says GPT-6 Astra Pro (covered in week 36) found them, with the original prompt and chat included alongside DESC checks and verification notebooks (MIT). Javier Gómez-Serrano, Lukas Liehr and Mitchell Taylor (arXiv 2609.24739) build families with only N-fold rotational symmetry and verify the proof in Lean 4; coverage says GPT and Claude models helped with calculations and Lean checking while the authors designed and checked the proof.