Popular Science | Silicon is Slow Factoring 15 is a problem fit for grade school students and cheap calculators, but it's not the size or speed of the calculation, merely the fact of it that matters in this case. Chuang's seven-"qubit" quantum computer, at the moment the most powerful one ever built, provides concrete evidence of a proposition that scientists just a few years ago thought unworkable: that the properties of atoms at the quantum level can reliably be exploited for the brains of a working computer. Indeed, the work of Chuang and others suggests that quantum machines may one day be capable of massively parallel computing, in which billions of calculations happen at once—a feat that will never be possible with silicon chips.