Evaluating NISQ Devices with Quadratic Nonresidues (2110.09483v2)

Abstract: We propose a new method for evaluating NISQ devices. This paper has three distinct parts. First, we present a new quantum algorithm that solves a two hundred year old problem of finding quadratic nonresidues (QNR) in polynomial time. We show that QNR is in Exact Quantum Polynomial time, while it is still unknown whether QNR is in P. Second, we present a challenge to create a probability distribution over the quadratic nonresidues. Due to the theoretical complexity gap, a quantum computer can achieve a higher success rate than any known method on a classical computer. A device beating the classical bound indicates quantum advantage or a mathematical breakthrough. Third, we derive a simple circuit for the smallest instance of the quadratic nonresidue test and run it on a variety of currently available NISQ devices. We then present a comparative statistical evaluation of the NISQ devices tested.