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Main Authors: Gal, Eshed, Eliasof, Moshe, Rout, Siddharth, Haber, Eldad
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2603.13663
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author Gal, Eshed
Eliasof, Moshe
Rout, Siddharth
Haber, Eldad
author_facet Gal, Eshed
Eliasof, Moshe
Rout, Siddharth
Haber, Eldad
contents The success of vision transformers-especially for generative modeling-is limited by the quadratic cost and weak spatial inductive bias of self-attention. We propose PDE-SSM, a spatial state-space block that replaces attention with a learnable convection-diffusion-reaction partial differential equation. This operator encodes a strong spatial prior by modeling information flow via physically grounded dynamics rather than all-to-all token interactions. Solving the PDE in the Fourier domain yields global coupling with near-linear complexity of $O(N \log N)$, delivering a principled and scalable alternative to attention. We integrate PDE-SSM into a flow-matching generative model to obtain the PDE-based Diffusion Transformer PDE-SSM-DiT. Empirically, PDE-SSM-DiT matches or exceeds the performance of state-of-the-art Diffusion Transformers while substantially reducing compute. Our results show that, analogous to 1D settings where SSMs supplant attention, multi-dimensional PDE operators provide an efficient, inductive-bias-rich foundation for next-generation vision models.
format Preprint
id arxiv_https___arxiv_org_abs_2603_13663
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle PDE-SSM: A Spectral State Space Approach to Spatial Mixing in Diffusion Transformers
Gal, Eshed
Eliasof, Moshe
Rout, Siddharth
Haber, Eldad
Machine Learning
The success of vision transformers-especially for generative modeling-is limited by the quadratic cost and weak spatial inductive bias of self-attention. We propose PDE-SSM, a spatial state-space block that replaces attention with a learnable convection-diffusion-reaction partial differential equation. This operator encodes a strong spatial prior by modeling information flow via physically grounded dynamics rather than all-to-all token interactions. Solving the PDE in the Fourier domain yields global coupling with near-linear complexity of $O(N \log N)$, delivering a principled and scalable alternative to attention. We integrate PDE-SSM into a flow-matching generative model to obtain the PDE-based Diffusion Transformer PDE-SSM-DiT. Empirically, PDE-SSM-DiT matches or exceeds the performance of state-of-the-art Diffusion Transformers while substantially reducing compute. Our results show that, analogous to 1D settings where SSMs supplant attention, multi-dimensional PDE operators provide an efficient, inductive-bias-rich foundation for next-generation vision models.
title PDE-SSM: A Spectral State Space Approach to Spatial Mixing in Diffusion Transformers
topic Machine Learning
url https://arxiv.org/abs/2603.13663