- Open Access
High-Dimensional Dynamics in Low-Dimensional Networks
Phys. Rev. X 16, 031025 – Published 3 August, 2026
DOI: https://doi.org/10.1103/79h2-36r3
Abstract
Many networks in nature and applications have an approximate low-rank structure in the sense that their connectivity structure is dominated by a few dimensions. It is natural to expect that dynamics on such networks would also be low-dimensional. Indeed, theoretical results show that low-rank networks produce low-dimensional dynamics whenever the network is isolated from external perturbations or input. However, networks in nature are rarely isolated. Here, we study the dimensionality of dynamics in recurrent networks with low-dimensional structure driven by high-dimensional inputs or perturbations. We find that dynamics in such networks can be high- or low-dimensional, and we derive mathematical conditions on the network structure under which linearized dynamics are high-dimensional. In many low-rank networks, dynamics are suppressed in directions aligned with the network’s low-rank structure, a phenomenon we term “low-rank suppression.” We show that several low-rank network structures arising in nature satisfy the conditions for generating high-dimensional dynamics and low-rank suppression. Our results clarify important but counterintuitive relationships between a recurrent network’s connectivity structure and the structure of its response to external input.
Physics Subject Headings (PhySH)
Popular Summary
Many networks exhibit low-dimensional structure, meaning they can be described by fewer variables than the number of variables comprising the network. Likewise, their dynamics or activity can also be low dimensional. This study investigates how a network’s structural dimensionality relates to the dimensionality of its dynamics, and specifically, its response to external inputs or noise. Using mathematical analysis and computer simulations, we demonstrate that networks with low-dimensional structure can yield either high- or low-dimensional responses. This outcome depends heavily on the finer structure of the network and its input. Furthermore, we reveal that networks with low-dimensional structure are less sensitive to inputs or perturbations aligned to their low-dimensional structure and are more sensitive to random and misaligned inputs. Ultimately, these findings offer important implications for how we interpret low-dimensional structures in real-world networks.
Article Text
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