News from China upset U.S. markets this week and disrupted the frenzy that had built up around artificial intelligence. A company called DeepSeek announced that it had developed a large language model that can compete with U.S. AI giants but at a fraction of the cost. DeepSeek had already hit the top of the chart for free apps on Apple’s App Store by Monday morning, and analysts said such a feat would be particularly impressive given how the U.S. government has restricted Chinese access to top AI chips. Chipmakers incurred some sizeable losses. Still, the noise in the tech sector...