Quantum-Merlin-Arthur Problems Have Perfect Completeness with an Infinite Counter

Author(s): Stacey Jeffery and Freek Witteveen A longstanding open problem in quantum complexity theory is whether Quantum Merlin-Arthur (QMA), the quantum analog of nondeterministic polynomial time, is equal to ${\mathrm{QMA}}_{1}$, its one-sided error variant. We show that $\mathrm{QMA}={\mathrm{QMA}}^{∞}={\mathrm{QMA}}_{1}^{∞}$, where ${\math… [Phys. Rev. Lett. 136, 180601] Published Wed May 06, 2026