Probing fundamental aspects of quantum mechanics with quantum computers

Abstract

IBM quantum computers are used to perform a recently-proposed experiment testing the necessity of complex numbers in the standard formulation of quantum mechanics. While the noisier devices are incapable of delivering definitive results, it is shown that certain devices possess sufficiently small error rates to yield convincing evidence that a faithful description of quantum phenomena must involve complex numbers. The results are consistent with previous experiments and robust against daily calibration of these devices. This work demonstrates the feasibility of using freely-available, noisy, intermediate-scale quantum devices to test foundational features of quantum mechanics.