Ising-inspired invertible adders using coupled phase-locked CMOS ring oscillators
Phys. Rev. Applied 24, 014004 – Published 1 July, 2025
DOI: https://doi.org/10.1103/8xc2-vkk3
Abstract
This paper is a contribution to the Physical Review Applied collection titled Physics-Inspired Computing.
Computational paradigms inspired by physics present a promising pathway for efficiently solving complex optimization problems by harnessing the intrinsic collective dynamics at the hardware level. We implement a prototype network of injection-locked and coupled complementary metal-oxide semiconductor ring oscillators, which, through their synchronized phase dynamics, spontaneously converge to solutions of Boolean satisfiability problems formulated as an Ising model. As a proof-of-concept demonstration, we experimentally realize the multidirectional operation of an invertible 1-bit full adder fabricated using 22-nm fully depleted silicon-on-insulator technology. This full adder features reconfigurable node clamping, enabling flexible instance encoding and facilitating simultaneous readout of all phase states. Expanding on this foundation, we investigate the scalability of these fundamental units into larger adder networks capable of performing both addition and subtraction operations, providing insight into the design-space trade-offs for scaling up to larger and harder problems.
Physics Subject Headings (PhySH)
Collections
This article appears in the following collection:
Collection on Physics-Inspired Computing
Physical Review Applied is pleased to present a Collection on Physics-Inspired Computing, highlighting the rapidly evolving field of energy-efficient computing techniques, from hardware technologies to algorithms, where physics inspiration serves as the crucial link. Contributions to this collection will be published throughout 2025. This Collection is being curated by Guest Editors Kerem Camsari and Supriyo Datta.
