From Superconducting Qubits to Distributed Nodes: Pathways of Operational Crosstalk

As quantum processors scale in size and complexity, sustaining high qubit fidelity amid constraints in connectivity, coherence, and control remains a major challenge. Distributed quantum computing (DQC) offers a modular path forward, linking smaller quantum subsystems through shared control and entanglement layers. However, these shared resources introduce potential interference channels and side-channel vulnerabilities.

We experimentally characterize multi-tenant operational crosstalk on superconducting hardware where shared control may amplify cross-module interference channels employed by the DQC. Simultaneous gate operations on neighboring qubits produce deterministic, operation-dependent correlations from cross-driving in common control electronics. Using controlled timing perturbations, we demonstrate that active interference amplifies these effects, inducing dephasing, fidelity loss, and temporal leakage of workload structure. Extending this analysis to DQC, we show that contention in shared entanglement or synchronization layers can yield analogous correlated errors. Finally, we explore isolation-aware scheduling as a mitigation strategy, showing how temporal workload decorrelation can suppress cross-tenant interference. The resulting sensitivity trends reveal control pathways most prone to crosstalk, offering practical insight for developing control-aware defenses that strengthen the robustness of future distributed quantum systems.