Scalable superconducting Qubit readout with millikelvin detection

Quantum computing is a game-changing technology that has the potential to revolutionize the way we approach computing and problem-solving. These last years, research groups around the world have made great strides in building quantum computers. One of the most promising is superconducting quantum technology, based on superconducting quantum bits (qubits). While plans to reach quantum computers with hundreds of qubits are in motion, the current technology is not yet scalable to sizes required for practical error-corrected applications, currently projected at millions of qubits.A critical hardware challenge today is scaling-up signal lines with cm-sized components connecting room-temperature electronics with qubits at millikelvin temperature in a dilution refrigerator. Such brute-force scaling would introduce unmanageable heat load and space constraints in modern refrigerators. Furthermore, increasing number of expensive and power-demanding room-temperature instrumentation additionally hinders the scaling process.The goal of SuperQold is to eliminate the hardware overhead preventing scaling, by revolutionizing the way superconducting qubits are read-out through currently unimaginable co-integration of superconducting qubits and cryo-CMOS electronics at millikelvin temperatures. By doing so, it will eliminate the need for large microwave components in output lines and expensive room-temperature acquisition instrumentation, enabling true scaling of signal routing and detection in quantum computers. Performing state detection near the qubits would for the first time enable future in-situ data processing and fast feedback schemes, ideal for quantum error detection and correction protocols.By achieving these key objectives, SuperQold will not only transform the way we build quantum computers, but also open new paradigms in quantum simulations, quantum sensing, superconducting electronics, and ultra-low power electronics.