#Nature #NewsFeature This billion-dollar firm plans to build giant quantum computers from light. Can it succeed?#PsiQuantum has ambitious goals to build a useful quantum machine by late 2027 — and has raised more than US$1 billion to do it. https://www.nature.com/articles/d41586-024-03827-y "PsiQuantum is aiming to jump to a machine that will require something in the order of one million qubits. (PsiQuantum’s researchers haven’t published a specific number.) “My impression is there’s a lot of scepticism about,” says Kolkowitz. He bets on them “extremely high risk”. A quantum computer will need around 10,000 physical qubits working together to make each useful ‘logical’ qubit, O’Brien says. Making a quantum computer with light is “on paper, quite easy”. But photons also come with hurdles. The company says it is building internal prototypes of increasing scale and complexity, but doesn’t market them as quantum computers. The firm has constructed prototype cabinet-sized devices, about 2 metres tall. A PsiQuantum’s computer would involve in the order of 100 devices."