Reconfigurable Superconducting Quantum Circuits Enabled by Micro-Scale Liquid-Metal Interconnects

TL;DR

This paper demonstrates the use of gallium-based liquid-metal interconnects for modular superconducting quantum circuits, enabling high-quality, reconfigurable connections with consistent performance across thermal cycles.

Contribution

It introduces liquid-metal interconnects as a novel, high-performance, reconfigurable solution for modular superconducting quantum circuits, overcoming fabrication and yield limitations.

Findings

Liquid-metal interconnects maintain high microwave performance.

Consistent device characteristics across thermal cycles.

Reformable superconducting connections after module replacement.

Abstract

Modular architectures are a promising route toward scalable superconducting quantum processors, but finite fabrication yield and the lack of high quality temporary interconnects impose fundamental limitations on system size. Here, we demonstrate chip-scale liquid-metal interconnects that show promise for plug-and-play superconducting quantum circuits by enabling non-destructive module replacement while maintaining high microwave performance. Using gallium-based liquid metals, we realize high-quality inter-module signal and ground interconnects, comparable in performance to conventional coplanar waveguide resonators. We illustrate consistent device characteristics across three thermal cycles between room temperature and 15 mK, as well as the ability to reform superconducting connections following module replacement. A width-dependent resonance frequency shift reveals a significant kinetic inductance fraction, which we attribute to the presence of $\beta$-phase tantalum as confirmed by X-ray characterization. Finally, we investigate power-dependent loss mechanisms and observe high-power dissipative nonlinearities qualitatively consistent with a readout-power heating model. These results establish liquid metals as viable chip-scale interconnects for reconfigurable, modular superconducting quantum systems.