Quantum error mitigation

In most of physics it is normal to obtain information by analysis of noisy data. The paradigm of quantum computing has been a simplified version of this -- one measurement of a two-level system gives one bit of reliable information about the result of a computation. But real-world quantum computers do not work this way: the noisiness of quantum evolution also requires good strategies for extracting information. This review covers many error-mitigation strategies used in present-day quantum processors. These strategies make it much more feasible to obtain useful results before fault tolerance is achieved.