A cavity-mediated reconfigurable coupling scheme for superconducting qubits

TL;DR

This paper presents a cavity-mediated, reconfigurable coupling scheme for superconducting qubits that allows dynamic, high-fidelity non-adjacent qubit interactions, enhancing quantum circuit flexibility.

Contribution

It introduces a tunable cavity-based architecture enabling selective, high-fidelity non-local qubit gates, advancing superconducting quantum processor design.

Findings

High-fidelity iSWAP and CZ gates within 50 ns

Residual $ZZ$ interaction below a few kHz during idling

Simulated gates between all qubit pairs with low crosstalk

Abstract

Superconducting qubits have achieved remarkable progress in gate fidelity and coherence, yet their typical nearest-neighbor connectivity presents constraints for implementing complex quantum circuits. Here, we introduce a cavity-mediated coupling architecture in which a shared cavity mode, accessed through tunable qubit-cavity couplers, enables dynamically reconfigurable interactions between non-adjacent qubits. By selectively activating the couplers, we demonstrate that high-fidelity iSWAP and CZ gates can be performed within 50 ns with simulated coherent error below $10^{-4}$, while residual $ZZ$ interaction during idling remains below a few kilohertz. Extending to a four-qubit system, we also simulate gates between every qubit pair by selectively enabling the couplers with low qubit crosstalk. This approach provides a practical route toward enhanced interaction flexibility in superconducting quantum processors and may serve as a useful building block for devices that benefit from selective non-local coupling.