The processing in quantum-based machines is noisy, which produces error rates dramatically higher than those of silicon-based computers. So quantum operations are repeated thousands of times to make the correct answer stands out statistically from all the wrong ones.
But running the same operation over and over again on the same qubit set may just generate the same incorrect answers that can appear statistically to be the correct answer. The solution, according to researchers at the Georgia Institute of Technology, is to repeat the operation on different qubit sets that have different error signatures which therefore won’t produce the same correlated errors. Choosing qubits with different error rates – and therefore different types of error – guards against that by ensuring that the one correct answer will rise above the diversity of errors.
The technique is known as Ensemble of Diverse Mappings (EDM). (Georgia Tech)