Impact and optimal timing of dynamical decoupling during syndrome extraction and readout

Ascertain the effect of the applied dynamical decoupling X pulses on idling qubits during GHZ-based syndrome extraction and readout in iceberg I{k} codes, and determine pulse-timing strategies that optimize logical fidelity and acceptance. Develop evidence-based guidance for when and how to schedule these dynamical decoupling pulses to yield net benefits in practical encoded experiments.

Background

To mitigate coherent dephasing during syndrome extraction and readout, the authors apply alternating-sign X pulses to idling qubits, ensuring an even number of pulses around stabilizer-extraction gates so as not to disturb code stabilizers. These pulses are used opportunistically in some experiments (e.g., certain SPAM runs with S_X extraction).

However, the authors report that the overall benefit of these pulses is not yet fully understood and may depend sensitively on their timing, suggesting the need for a careful study to quantify their impact and to optimize scheduling policies in iceberg-code workflows.