Physicists have cracked a long-standing puzzle in quantum gravity: single-minus graviton amplitudes were thought to always vanish at tree level, but a new preprint proves they don’t—provided particles are in a special kinematic regime called half-collinear. The team, including researchers from Harvard, Cambridge, and OpenAI, used GPT-5.2 Pro to derive explicit formulas for these interactions. This matters because it reveals a hidden w-(1+∞) symmetry connecting classical and quantum gravity, moving us a step closer to unifying Einstein’s theory with quantum mechanics.