Curator's Take
This breakthrough addresses one of quantum computing's most pressing scalability challenges by demonstrating that quantum control electronics can operate directly alongside qubits at ultra-low temperatures, eliminating the need for complex room-temperature control systems connected via lengthy cables. The 99.9% gate fidelity achieved with this "plug-and-play" superconducting controller represents a significant milestone, as it matches or exceeds the performance of traditional control methods while consuming just 0.121 femtojoules per operation. This ultra-low power consumption is crucial for scaling to thousands or millions of qubits, where heat generated by control electronics could otherwise overwhelm dilution refrigerators and destroy the delicate quantum states. The chip-to-chip integration approach demonstrated here could fundamentally reshape quantum computer architecture, bringing us closer to the large-scale fault-tolerant systems needed for practical quantum advantage.
— Mark Eatherly
Summary
The development of large-scale superconducting quantum computing requires efficient in-situ control methods that allow high-fidelity operations at millikelvin temperatures. Superconducting circuits based on Josephson junctions offer a promising solution due to their high speed, low power dissipation, and cryogenic nature. Here, we report a superconducting quantum controller that enables direct chip-to-chip interconnection with qubits at 10 mK and high-fidelity, all-digital manipulation. Randomized benchmarking reveals a uniformly high average Clifford fidelity of 99.9% with leakage to high energy levels on the order of $10^{-4}$, and an estimated average gate operation energy of 0.121 fJ, demonstrating the potential to resolve the control bottleneck in superconducting quantum computing.