Impact of Timing and Sequence Design on Spectator-Induced Dephasing in Superconducting Qubits

Dynamical Decoupling (DD) is a powerful method for reducing decoherence in superconducting quantum systems. This study examines how DD sequence timing affects spectator-induced dephasing in neighboring qubits. We observe that the excited states of adjacent qubits significantly impact the coherence of operational qubits. DD sequences applied to these qubits effectively suppress this dephasing, even when qubits remain in superposition states. Our analysis of Carr-Purcell-Meiboom-Gill (CPMG) sequences reveals that precise timing is crucial for achieving optimal coherence enhancement. Delays in sequence implementation can diminish the protective effect. These findings emphasize the importance of careful timing for multi-qubit circuit optimization.