Nature Computational Science · Article

Scalable physical deep learning using optical dynamics with state-skipping training and single-map architecture

Yongbo Zhang, Mitsumasa Nakajima, Katsuma Inoue, Toshikazu Hashimoto, Yasuo Kuniyoshi & Kohei Nakajima
Received 18 November 2025 · Accepted 30 September 2026
Source: doi:10.1038/s43588-026-01075-w · Original PDF, page 1

Abstract

Escalating energy demands for high-performance machine learning have sparked growing interest in unconventional computing paradigms rooted in physical systems. Central to this direction is leveraging physical properties to design computing frameworks integrating strong learning capabilities, efficient training strategies and practical implementability. Here we present a simple, efficient and scalable framework aimed at achieving this, validated on an optoelectronic platform. This framework features our proposed training mechanism, state-skipping direct feedback alignment, together with our single-map architecture based on simple one-dimensional dynamics. The former eliminates the need to access the system’s intermediate states during training, substantially simplifying error backpropagation, while the latter removes complex internal interconnections. Together, they enhance training efficiency and practical feasibility. Compared with conventional deep neural networks, our approach substantially reduces computational costs and trainable parameter count while achieving comparable performance. Integrated into modern architectures, our scheme attains improved performance with an approximately 40% reduction in computational resources. Notably, our approach challenges the scaling laws of conventional counterparts, underscoring its strong scalability and practical promise.

Opening text

Deep learning has performed remarkably well across complex tasks, but continued model scaling sharply increases energy and hardware-resource demands, raising sustainability concerns1–3. Computationally efficient paradigms become a priority. Unconventional computing based on physical platforms is increasingly recognized as a promising route around these bottlenecks. Unlike conventional Von Neumann architectures separating processing and memory, these paradigms harness physical processes for information processing, offering inherent latency and energy efficiency advantages4–8.