Inherent flux crosstalk and coupler-driven single-qubit gates in superconducting circuits

Unwanted qubit interactions, termed crosstalk, fundamentally limit the scalability and operational performance of quantum information systems. This issue is particularly acute in superconducting qubit architectures, where the very mechanisms enabling high-fidelity entangling gates — namely, tunable couplings and frequency adjustments actuated by external magnetic fluxes — inherently introduce this detrimental effect¹. This "inherent flux crosstalk" leads to unintended qubit addressing, directly degrading the overall fidelity and stability of quantum circuits. The research explores the complex interplay of these flux-driven interactions, even in the context of coupler-driven single-qubit gates, highlighting how precise control mechanisms can paradoxically introduce systemic errors. Understanding how these intrinsic electromagnetic interferences manifest is critical, as they can corrupt quantum states and introduce computational errors, thereby preventing the reliable execution of complex algorithms on larger systems. Effectively characterizing and mitigating this inherent flux crosstalk is therefore paramount for developing stable, scalable superconducting quantum processors capable of advanced computation.