Ability of error correlations to improve the performance of variational quantum algorithms

Recent experiments indicate that uncorrelated noise models may not be enough to explain the physical behavior of quantum devices, and that correlated error must be taken into account. Here, the authors use a simple model to numerically study variational quantum algorithms with error that is correlated either in time or in space. They find that correlated error can actually improve algorithm performance, due to the fact that there are simply more ways for uncorrelated errors to occur in a system.