Liquid metal printing for superconducting circuits

TL;DR

This paper demonstrates that liquid-metal micro-pipette printing can effectively fabricate high-quality superconducting circuits, offering a new additive manufacturing approach that preserves circuit integrity and enhances scalability for quantum computing hardware.

Contribution

It introduces a novel liquid-metal printing technique for superconducting circuits, enabling local metal addition without damaging existing structures and maintaining high quantum coherence.

Findings

High internal quality factors achieved in superconducting resonators

Additive printing preserves preexisting circuit elements

Potential for scalable quantum computer hardware

Abstract

Superconducting circuits are a promising platform for implementing fault-tolerant quantum computers, quantum limited amplifiers, ultra-low power superconducting electronics, and sensors with ultimate sensitivity. Typically, circuit fabrication is realized by standard nanolithography, generally associated with a high level of control over defects and contaminants. Additive approaches have not been used so far since they are expected to be inferior in terms of superconducting properties or quantum coherence. This work shows that liquid-metal based micro-pipette printing is suited for fabricating superconducting lumped-element resonators with high internal quality factors. The applicability of our technique for low-loss superconducting device fabrication and the possibility to locally add metal structures, without affecting any preexisting circuit elements, is a further advantage. Our results open up new avenues in the hardware implementation of scaled-up superconducting quantum computers.