  Building a modular architecture with superconducting quantum computing chips
is one of the means to achieve qubit scalability, allowing the screening,
selection, replacement, and integration of individual qubit modules into large
quantum systems. However, the nondestructive replacement of modules within a
compact architecture remains a challenge. Liquid metals, specifically gallium
alloys, can be alternatives to solid-state galvanic interconnects. This is
motivated by their self-healing, self-aligning, and other desirable fluidic
properties, potentially enabling the nondestructive replacement of modules at
room temperatures, even after operating the entire system at millikelvin
regimes. In this study, we present coplanar waveguide resonators (CPWRs)
interconnected by gallium alloy droplets, achieving high internal quality
factors up to nearly one million and demonstrating performance on par with the
continuous solid-state CPWRs. Leveraging the desirable fluidic properties of
gallium alloys at room temperature and their compact design, we envision a
modular quantum system enabled by liquid metals.
