Edoardo Charbon

Controlling and reading out qubits with high fidelity and nanosecond latency requires radio-frequency pulses with a precision of a few kHz in frequency, better than 1o in phase, and better than 1 ns in pulse width. The amplitude and shape of the envelope must be programmable and sequenced precisely. On the readout side, the input-referred noise must be better than a 0.1 nV/√Hz, with a gain higher than 80 dB. This is due to the extremely weak signals from the qubits that require highly sensitive circuits and systems, along with very precise timing capability. We advocate the use of CMOS technologies to achieve these goals, whereas the circuits will be operated at deep-cryogenic temperatures and dissipate no more than 1mW/qubit to control 1000 qubits in a conventional dilution refrigerator [1]. We believe that these circuits, collectively known as cryo-CMOS control, will make future qubit arrays scalable, enabling a faster growth in qubit count. Moreover, the challenges of modeling, designing, and operating complex circuits and systems at 4K and below will be outlined, along with preliminary results achieved in the control and readout of qubits by ad hoc integrated circuits that were optimized to operate at low power in these conditions. We will conclude with a perspective on the field and its trends.

[1] E. Charbon, F Sebastiano, A Vladimirescu, H Homulle, S Visser, L Song, R M Incandela, “Cryo- CMOS for Quantum Computing, pp. 1351-1354, IEDM (2016).

[2] Y. Peng, A. Ruffino, T.-Y. Yang, J. Michniewicz, M. F. Gonzalez-Zalba, E. Charbon, “A Cryo- CMOS Wideband Quadrature Receiver with Frequency Synthesizer for Scalable Multiplexed Readout of Silicon Spin Qubits”, 57(8), pp. 2374-2389, JSSC (2022).