Quantum computing is widely recognized as one of the most transformative technologies of the coming decades, with the potential to revolutionize fields ranging from drug discovery and materials science to cryptography and optimization. Among the various hardware approaches being pursued, superconducting quantum computers have emerged as one of the most promising platforms, with heavy investments from major technology players and research institutions. However, scaling these systems beyond a few hundred quantum bits (“qubits”), a prerequisite for achieving practical quantum advantage, remains an enormous engineering challenge.
One of the most critical yet underappreciated bottlenecks lies in the qubit readout chain. In current superconducting architectures, the readout chain spans from the output of the quantum processing unit (QPU) at temperatures close to absolute zero, all the way up to room temperature electronics. Along this chain, multiple bulky and expensive components hamper larger scale integration. As the number of qubits grows, so does the complexity and physical footprint of the readout chain, making it one of the principal obstacles to building truly scalable quantum computers.
This SQELETON project, which stands for Scalable Qubit Readout to Resolve Superconducting Quantum Computing’s Skeleton in the Closet, directly addresses this challenge. Funded by the European Innovation Council under its Transition program, the project is led by Silent Waves, a deep-tech startup based in Grenoble, France, that has spun out of the Institut Néel lab (CNRS) more than four years ago, in January 2022. Silent Waves has developed a pioneering device called the Travelling Wave Parametric Amplifier and Isolator (TWPAI), which combines forward amplification and backward isolation into a single compact component at cryogenic temperatures. This has the potential to drastically alleviate the size, complexity, and cost of qubit readout infrastructure, paving the way for a scalable generation of readout hardware.
The ultimate ambition of SQELETON is to bring the TWPAI from laboratory demonstration to validation in a real use case by the end of the first project year, then progressing towards a validated market-ready prototype by 2028. In doing so, the project contributes directly to Europe’s strategic objectives in quantum technologies, supporting the goals of the European Quantum Flagship and reinforcing the continent’s technological sovereignty.
