Superconducting Digital Electronics for Controlling Quantum Computing Systems

Abstract

The recent rapid increase in the scale of superconducting quantum computing systems greatly increases the demand for qubit control by digital circuits operating at qubit temperatures. In this paper, superconducting digital circuits, such as single-flux quantum and adiabatic quantum flux parametron circuits are described, that are promising candidates for this purpose. After estimating their energy consumption and speed, a conceptual overview of the superconducting electronics for controlling a multiple-qubit system is provided, as well as some of its component circuits. key words: qubit, quantum computing, single-flux quantum circuit, adiabatic quantum flux parametron circuit, superconducting integrated circuits Nobuyuki Yoshikawa received the B.E., M.E., and Ph.D. degrees in electrical and computer engineering from Yokohama National University, Japan, in 1984Japan, in , 1986Japan, in , and 1989, respectively. Since 1989, he has been with the Department of Electrical and Computer Engineering, Yokohama National University, where he is currently a Professor. His research interests include superconductive devices and their application in digital and analog circuits. He is also interested in single-electron-tunneling devices, quantum computing devices and cryo-CMOS devices. He is a member of

MANA: A Monolithic Adiabatic iNtegration Architecture Microprocessor Using 1.4-zJ/op Unshunted Superconductor Josephson Junction Devices

“…Our implementation of MANA is nowhere near the complexity and performance of the aforementioned architectures, but its successful low-speed functional demonstration along with the high-speed demonstration of its EX stage indicate that AQFP logic can indeed perform practical adiabatic computation. The extremely low switching energy and relatively high-clock rates (2-5 GHz) of AQFP logic also enable it to interface closely to superconductor-based qubits in the form of a controller for the read-out of quantum states for quantum computing [55]. With further refinement in the design methodologies to improve area efficiency and latency and the emergence of superconductor EDA tools to help with flux trapping analysis, system-level integration, and clocking, more feature-rich performance-driven AQFP circuits may be feasible in the near future.…”

Sharp-selectivity in-line topology low temperature superconducting bandpass filter for superconducting quantum applications

“…Recently, low temperature superconducting (LTS) microwave circuits have been extensively investigated for superconducting quantum computing systems [5][6][7][8][9]. Specifically, we have been developing an on-chip rapid singleflux-quantum microwave pulse generator (RSFQ MPG) [10,11] to control superconducting qubits in a scalable quantum computing system [12]. Figure 1 illustrates the schematic of an RSFQ MPG.…”