The Download: a useful quantum machine and a record-breaking subsea tunnel

This is today’s edition of The Download , our weekday newsletter that provides a daily dose of what’s going on in the world of technology. PsiQuantum has a plan to make a massive quantum computer out of light The machine that could change the world will be housed in a room that looks like a data center crossed with an ice cream factory. Inside, some 100 stainless-steel cabinets each hold hundreds of chips. On those chips, thousands of light particles will fly through a maze of optical switches and beam splitters. Each photon must be accounted for, because precisely measuring where it ends up will help answer questions that current computers might take millions of years to solve. This computer, as described, does not exist. It’s the brainchild of a company called PsiQuantum, founded in 2016 by four physicists from UK universities. In a crowded field of deep-pocketed competitors with similarly fantastical visions, the company aims to be the first to build a useful quantum machine. Read the full story on the company’s quest . —James O’Donnell MIT Technology Review Narrated: inside the world’s deepest and longest subsea road tunnel —Niall Firth I’m currently around 1,000 feet beneath the North Sea, in a dark, dank cave. It smells weird. And I’m increasingly aware of the pressure from millions of tons of seawater just above my head. I’m under the iconic fjords of Norway to visit what will soon become the world’s longest and deepest subsea road tunnel—an exceptional engineering feat that will carry drivers deep beneath the North Sea. I’m here to understand how you make a 16.6-mile highway that sits 1,280 feet below the sea at its deepest point. And also—at a time when it can feel hard to get anything done—to reassure myself that ambitious engineering is still possible. That we can still make things . This is our latest story to be turned into an MIT Technology Review Narrated podcast, which we publish each week on Spotify and Apple Podcasts . Just navigate to MIT Technolo