arXiv Machine Learning

A Bifurcation Theory Framework for Gradient Descent on the Edge of Stability

arXiv:2606. 15551v1 Announce Type: new Abstract: The Edge of Stability (EoS) phenomenon, where gradient descent operates with sharpness exceeding the classical convergence threshold yet the loss decreases over long timescales, is ubiquitous in modern deep learning but remains poorly understood in realistic settings.

arXiv Machine Learning
Aug 20

The Road Taken: The Role of Optimizers at the Edge of Stability

The paper investigates the "edge of stability" phenomenon in deep learning, where Hessian eigenvalues remain stable above a classically predicted unstable threshold. It shows that many first‑order optimizers, including gradient descent, can violate this stability bound by up to a factor of 21.1, and that this deviation depends systematically on the optimizer used. The authors propose a new stability threshold based on the directional Hessian and gradient‑alignment score, which removes optimizer‑dependent offsets and offers consistent predictions while providing diagnostic tools to understand how optimizers balance temporal and spatial budgets.

By Jaerin Lee, Kyoung Mu Lee
arXiv Machine Learning
Aug 19

Center-Manifold Reduction of Learning at Bifurcations: Interference and Rich Learning in Recurrent Neural Networks

The paper investigates how gradient descent behaves near codimension‑one bifurcations in recurrent neural networks by analyzing the global empirical Neural Tangent Kernel (GeNTK). Under local center‑manifold conditions, the parameter‑to‑state Jacobian is approximated by a low‑rank normal‑form operator, causing the GeNTK and Fisher information matrix to become strongly amplified and anisotropic, concentrating on a rank‑one or rank‑two channel depending on the bifurcation type. Experiments on high‑dimensional RNNs confirm that this low‑rank concentration coincides with abrupt loss changes, subtask interference, and aligns with changes in memory dynamics in a 15‑task LeakyRNN.

By James Hazelden, Eric Shea-Brown
arXiv Machine Learning
Sep 17

Beyond Quadratic Loss: The Stability Phase Diagram of Adam

The paper studies how Adam’s two momentum timescales, β1 and β3, influence loss spikes during neural‑network training. By mapping training dynamics across the (β1,β3) plane, the authors find an approximately linear boundary, 1-β3 = C(1-β1), that separates spiky from non‑spiky behavior, with the coefficient C linked to the effective loss exponent in superquadratic loss functions. They also show that confident cross‑entropy losses create a core–wall landscape that behaves superquadratically at the scale of an optimizer update, explaining the observed spikes.

By Gaoxiang Tang, Huanran Chen, Ziming Liu
arXiv Machine Learning
Jun 30

Non-Euclidean Gradient Descent Operates at the Edge of Stability

arXiv:2603. 05002v3 Announce Type: replace Abstract: The Edge of Stability (EoS) is a phenomenon where the sharpness (largest eigenvalue) of the Hessian approaches and then hovers near the stability threshold $2/\eta$ during gradient descent (GD) with step size $\eta$.

By Rustem Islamov, Michael Crawshaw, Jeremy Cohen, Robert Gower
arXiv Machine Learning
Jul 16

How the Hessian-Spectrum of Neural Networks Depends on Data

arXiv:2607. 13631v1 Announce Type: new Abstract: The Hessian matrix is an important quantity of interest when it comes to studying the loss landscape and optimization dynamics in deep learning, as well as designing measures of generalization, second-order learning algorithms, etc.

By Jasraj Singh, Enea Monzio Compagnoni, Antonio Orvieto