Architectural Challenge for Cryogenic Superconductor Computing

Single-flux-quantum (SFQ) logic operating in a 4.2-kelvin environment with a superconducting state is a promising candidate for achieving extremely high-performance, low-power computing. Josephson junctions (JJs) are used as switching elements in SFQ logic to compose a superconductor ring that can store and transfer a single magnetic flux quantum. It fundamentally operates with the voltage pulse-driven nature, making achieving extremely low-latency and low-energy JJ switching possible. This talk presents our computer architecture research activities for SFQ logic by targeting classical and quantum computers. The key insight we have learned was that deep, efficient collaboration of computer architects and device scientists has significant potential to make breakthroughs in computer system designs. Based on such concrete collaboration, we have introduced state-of-the-art architectural techniques for classical computing targeting SFQ-based processing elements, AI accelerators, etc. Then now, we are trying to extend our technologies for superconductor qubit control/management required to achieve 1 OK+ scalable cryogenic quantum computers. This talk finally discusses the future trends of such next-generation computer architecture designs.