Christian Weedbrook, the founder and CEO of Toronto-based Xanadu Quantum Technologies, became a billionaire this week without NVIDIA investing a single dollar in his company. His 46.4 million multiple-voting shares were worth approximately $1.5 billion as of midday Friday, after Xanadu’s stock surged nearly fivefold in six trading sessions. The catalyst was not anything Xanadu did. It was NVIDIA announcing a suite of open-source AI models and a new hardware architecture designed to accelerate quantum computing, which sent the entire sector into a rally that made Xanadu, the only publicly traded pure-play photonic quantum computing company, the most dramatic beneficiary. Xanadu went public on 27 March via a SPAC merger with Crane Harbor Acquisition Corp., listing on both the Nasdaq and the TSX. The stock was already up from its IPO price when NVIDIA’s announcements began landing on 14 April. It rose 17% on Friday, 28% on Monday, 29% on Tuesday, and 70% on Wednesday, when the Canadian Investment Regulatory Organization imposed five trading halts in a single session. The stock has gained roughly 194% since listing. What NVIDIA actually did NVIDIA did not buy Xanadu shares, sign a contract with the company, or name it as a partner. What it did was make quantum computing look closer to useful than it has ever looked before, and the market priced that in across every quantum stock simultaneously. On 14 April, NVIDIA launched Ising, a family of open-source AI models designed to solve the two problems that have kept quantum computers from being practical: error correction and calibration. The error correction models are up to 2.5 times faster and three times more accurate than current industry standards. The calibration models reduce quantum processor setup time from days to hours. Both address bottlenecks that have made quantum hardware expensive to operate and