The unavoidable finite time intervals between the sequential operationsneeded for performing practical quantum computing can degrade the performanceof quantum computers. During these delays, unwanted relative dynamical phasesare produced due to the free evolution of the superposition wave-function ofthe qubits. In general, these coherent "errors" modify the desired quantuminterferences and thus spoil the correct results, compared to the idealstandard quantum computing that does not consider the effects of delays betweensuccessive unitary operations. Here, we show that, in the framework of thequantum phase estimation algorithm, these coherent phase "errors", produced bythe time delays between sequential operations, can be avoided by setting up thedelay times to satisfy certain matching conditions.
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