Scalable Suppression of XY Crosstalk by Pulse-Level Control in Superconducting Quantum Processors

TL;DR

This paper introduces a scalable pulse-level control method using frequency modulation and dynamical decoupling to significantly reduce XY crosstalk errors in dense superconducting quantum processors, enhancing fidelity.

Contribution

It presents a novel, scalable pulse-level control framework that suppresses XY crosstalk independently of coupling strengths, reducing calibration needs and supporting multi-qubit connectivity.

Findings

Orders-of-magnitude reduction in infidelity for idle and single-qubit gates.

Effective crosstalk suppression demonstrated in a five-qubit layout.

Framework operates independently of coupling strengths, supporting dense architectures.

Abstract

As superconducting quantum processors continue to scale, high-performance quantum control becomes increasingly critical. In densely integrated architectures, unwanted interactions between nearby qubits give rise to crosstalk errors that limit operational performance. In particular, direct exchange-type (XY) interactions are typically minimized by designing large frequency detunings between neighboring qubits at the hardware level. However, frequency crowding in large-scale systems ultimately restricts the achievable frequency separation. While such XY coupling facilitates entangling gate operations, its residual presence poses a key challenge during single-qubit controls. Here, we propose a scalable pulse-level control framework, incorporating frequency modulation (FM) and dynamical decoupling (DD), to suppress XY crosstalk errors. This framework operates independently of coupling strengths, reducing calibration overhead and naturally supporting multi-qubit connectivity. Numerical simulations show orders-of-magnitude reductions in infidelity for both idle and single-qubit gates in a two-qubit system. We further validate scalability in a five-qubit layout, where crosstalk between a central qubit and four neighbors is simultaneously suppressed. Our crosstalk suppression framework provides a practical route toward high-fidelity operation in dense superconducting architectures.