Roadmap on nanoscale superconductivity for quantum technologies

Yariv Yanay, Daniel Campbell, Jochen Braumüller +2 more

B. L. T. Plourde, Timothy L. Robertson, Antonio García Martínez +5 more

Yuriy Makhlin, Gerd Schön, Alexander Shnirman

Oleksandr V. Dobrovolskiy, Hermann Suderow, Francesco Tafuri +61 more

Abstract In 2025, the Year of Quantum Science and Technology ( https://quantum2025.org/ ), we celebrate a century of quantum mechanics, witnessing a surge in activities that illuminate its inherent strangeness and drive technological innovation. Superconductivity, discovered 114 years ago, stands as a prime example, offering direct and compelling evidence of macroscopic quantum phenomena. Beyond its ability to conduct immense currents without loss, superconductivity reveals the quantum realm operating on a scale we can directly observe and manipulate. The macroscopic quantum coherence, where an ensemble of particles is described by a single wave function, leads to remarkable consequences: dissipation-less current and flux quantization—the basic properties exploited in superconducting quantum circuit fabrication. This Roadmap has been inspired by intensive discussions and collaborations emerging from the European Cooperation in Science & Technology COST-Action CA21144 (SuperQuMap—Superconducting Nanodevices and Quantum Materials for Coherent Manipulation). The aim of the COST Action SuperQuMap is to establish a strong European network centered on macroscopic quantum behavior in superconductors, bringing together groups of different backgrounds and more than 30 countries. The roadmap outlines the network’s concrete activities, driving advancements in superconductor-based quantum technologies and charting future directions. Spanning fundamental research to practical applications, the roadmap incorporates insights from industry partners developing quantum computation. It begins by exploring quantum materials, highlighting how topology and electronic correlations could catalyze a quantum leap in technology. We then delve into manipulating the superconducting phase, leveraging advancements in magnetism, 3D fabrication, and tunable correlations. Further, we showcase the advanced microscopy techniques—such as angle-resolved photoemission spectroscopy and scanning probes—used to visualize quantum behavior. Finally, and crucially, we detail the quantum devices developed within the network, and their transformative impact on modern quantum computing approaches.

J. M. Rowell

For some time, work has been continuing within the U.S.A. on a "Technology Roadmap for the Superconducting Electronics Industry". A similar roadmap exercise is underway in Europe, and in Japan, recently announced research projects in superconductivity involved a detailed planning process. However, the U.S. Roadmap is not complete, and a consensus of industry opinion has not yet been reached on its recommendations. This manuscript should be regarded as a distillation of inputs from many sources, heavily weighted with the author's own prejudices. He suggests that a system level view of superconducting electronics technology should lead to revisions of today's research priorities. In particular, the importance of the cryocooler and cryopackage in each system has broad implications, even affecting the directions of materials and device research.

Satyavolu S. Papa Rao