US Patent 10055690 Quantum leakage suppression method

A method of reducing quantum leakage in a qubit device which includes receiving a set of energy level values for a multi-level system which includes first and second working levels |0>, |1> which provide a qubit, and at least one other level |2>, and performing an iteration of determining quantum leakage from at least one of the first and second working levels to the at least one other level for a quantum operation A for at least one pulse wherein each pulse has a respective pulse duration, determining whether the quantum leakage is greater than or equal to a threshold value; and, based on the quantum leakage being greater than or equal to the threshold value, changing the duration of at least one of the at least one pulse.