Why Quantum Computing Is Arriving Sooner Than You Think

For most of its history, useful quantum computing has been the technology of the day after tomorrow, forever a comfortable couple of decades away. That reflexive answer is starting to look out of date. A steady run of genuine results over the past few years has convinced many of the people closest to the field that quantum computing is arriving sooner than the old consensus assumed, and they have quietly revised their timelines forward rather than back. This is not a claim that a quantum laptop is about to appear on your desk, and the surrounding hype deserves every bit of the scepticism it attracts. The argument here is narrower and more interesting. The specific obstacles that once made useful machines look distant, above all the problem of errors, are falling faster than almost anyone predicted, and the money and talent needed to exploit that are arriving at the same time. What follows lays out the evidence in detail, signal by signal, and then gives the honest reasons for caution. The aim is not to cheerlead but to explain why a faster arrival has moved from a fringe opinion to a mainstream one, and what that shift does and does…