In computer science, NP refers to problems where a solution can be verified quickly, even if finding that solution may take enormous time. This class has guided much of modern complexity theory. Its quantum counterpart is QMA, where a proof comes not as a string of bits but as a fragile quantum state. Researchers now say OpenAI’s GPT-5 has helped prove strict limits on QMA. The model suggested a mathematical expression that led to a breakthrough on how far error reduction can go.