  Overcoming the influence of noise and imperfections is a major challenge in
quantum computing. Here, we present an approach based on applying a desired
unitary computation in superposition between the system of interest and some
auxiliary states. We demonstrate, numerically and on the IBM Quantum Platform,
that parallel applications of the same operation lead to significant noise
mitigation when arbitrary noise processes are considered. We first design
probabilistic implementations of our scheme that are plug and play, independent
of the noise characteristic and require no postprocessing. We then enhance the
success probability (up to deterministic) using adaptive corrections. We
provide an analysis of our protocol performance and demonstrate that unit
fidelity can be achieved asymptotically. Our approaches are suitable to both
standard gate-based and measurement-based computational models.
