Two Weeks After a Million Qubits, the Harder Question Is What They Verify

SINGAPORE — The million-qubit processor the Singapore Institute ran over the Q-Net backbone two weeks ago has already receded from headline to homework. The demonstration proved that a machine of that scale could hold together over the quantum-secured network; the question filling seminar rooms now is narrower and harder — what can it verify that a smaller machine cannot. "Scale is a number," said physicist Dr. Wei-Lin Tan, who helped present the result. "Trust is a proof." Tan is careful to correct a persistent public error: the Q-Net secures the channel, it does not send information faster than light — entanglement guarantees no one has listened, nothing more. The Institute is now applying the processor to verification problems in materials chemistry, where classical checking grows unwieldy. It is, Tan concedes, less thrilling than a record. "Records are for one afternoon," she said. "Verification is for every afternoon after."