Quantum computing's prospects: How long will it be before we see practical quantum-computing machines? - [Spectral Lines]

Our romance with new technologies always seems to follow the same trajectory: We are by turns mesmerized and adoring, disappointed and disheartened, and end up settling for less than we originally imagined. In 1954, Texas Instruments touted its new transistors as bringing "electronic “brains” approaching the human brain in scope and reliability" much closer to reality. In 2000, U.S. president Bill Clinton declared that the Human Genome Project would lead to a world in which "our children's children will know the term cancer only as a constellation of stars." And so it is now with quantum computing. ¶The popular press is awash with articles touting its promise. Tech giants are pouring huge amounts of money into building prototypes. You get the distinct impression that the computer industry is on the verge of an imminent quantum revolution. ¶But not everyone believes that quantum computing is going to solve real-world problems in anything like the time frame that some proponents of the technology want us to believe. Indeed, many of the researchers involved acknowledge the hype has gotten out of control, cautioning that quantum computing may take decades to mature. ¶Theoretical physicist Mikhail Dyakonov, a researcher for many years at Ioffe Institute, in Saint Petersburg, Russia, and now at the University of Montpellier, in France, is even more skeptical. In "The Case Against Quantum Computing," on p. 24 of this issue, he lays out his view that practical general-purpose quantum computers will not be built anytime in the foreseeable future. ¶As you might expect, his essay ruffled some feathers after it was published online. But as it turns out, while his article was being prepared, a committee assembled by the U.S. National Academies of Sciences, Engineering, and Medicine had been grappling with the very same question.