I. Introduction
The idea that quantum effects could be harnessed to allow faster computation was first proposed by Feynman [1]. Fast forwarding to the present date, Google inc. has recently provided us with the first serious claim of ‘quantum supremacy’, that is, a quantum computer that performs a given task faster than its classical counterpart [2]. Whether or not these claims are validated, their theoretical possibility is unambiguously predicted by quantum mechanics, based principles which have not been overturned since their initial proposal in the 1920s despite extensive empirical testing. If, as some sceptics claim, we were to find quantum supremacy unattainable, this would in fact be an even more interesting outcome from the physicist’s point of view, as it would reveal something fundamentally new to us about the universe ([3], though note that the author of this citation considers the result likely to prevail). We live in exciting times; nonetheless, quantum computing is still in its infancy.