arXiv Machine Learning

Lyapunov Exponent as Physics-Informed Dense Reward: RL Discovery of Stabilization Beyond the Kapitza Pendulum

arXiv:2607. 14001v1 Announce Type: new Abstract: We suggest using the Lyapunov characteristic exponent (LCE) as a dense reward signal for the reinforcement learning problem of stabilizing the inverted pendulum with vertical motion.

arXiv Machine Learning
Oct 3

Bellman Meets Lyapunov: Unsupervised Reinforcement Learning via Mastering Chaos

The paper introduces Forward CIP (F‑CIP), an RL‑native formulation of the Controllable Information Production objective that relies solely on system dynamics, eliminating the need for domain‑specific information variable selection. F‑CIP is proven compatible with reinforcement learning and, when applied to existing algorithms, enables agents to autonomously discover primitive behaviors such as balancing and maintaining controllability. Coupled with a simple forward‑velocity reward, the method yields coordinated gaits like hopping and running without reward engineering.

By Tristan Shah, Wooyoung Chung, Volodomyr Makarenko, Juan Wachs, Stas Tiomkin
arXiv Machine Learning
Sep 7

Variational Continuation for Double Pendulum Periodic Orbits

The paper introduces a Hessian‑based, integrator‑free method for numerically continuing periodic orbits in dynamical systems, using a Fourier series representation and automatic differentiation to avoid hand‑derived Jacobians. By exploiting flat directions in the loss landscape, the approach efficiently guides the search for periodic orbits, accurately initializes oscillations around unstable fixed points, and detects orbit family intersections and subharmonic bifurcations. Demonstrated on the double pendulum, the method produces full continuations from fixed points, revealing bifurcations along orbit families and identifying previously undocumented periodic orbits where both pendulum masses are never simultaneously at rest.

By Leo Yao, Ziming Liu, Max Tegmark
arXiv AI
Aug 19

Policy-Invariant Reward Shaping from LLM Feedback: A Framework for Hybrid RL Agents

The paper introduces a framework for combining large language models (LLMs) with reinforcement learning (RL) by treating the LLM as a planner and the RL agent as a controller. It formalizes this hybrid setup as a Goal-Augmented Markov Decision Process and proves that using the LLM’s per‑state progress score as a bounded potential function preserves the optimal policy set, even if the LLM scores are inaccurate. The authors validate their theoretical result with numerical experiments on a small MDP, testing four potential configurations, including an adversarial case with a potential scaled twenty times the base reward.

By Christophe D. Hounwanou, John Emeka Eze, Ya\'e U. Gaba
Towards Data Science
Sep 5

Dynamical System Transfer Learning with Reduced Order Models

The article "Dynamical System Transfer Learning with Reduced Order Models" discusses how to enhance reinforcement learning for complex physics problems by employing reduced order models. It explores the application of transfer learning techniques to dynamical systems, aiming to improve the efficiency and effectiveness of reinforcement learning algorithms in physics-based simulations.

By Robert Etter
arXiv Machine Learning
Aug 19

Reinforcement Learning as (Discrete) Potential Theory

The paper discusses how reinforcement learning theory relies on probability theory via Markov chains and highlights a deep link between probability theory and potential theory. It reviews this connection and examines how a potential-theoretic perspective can be applied to core RL representations and algorithms under a fixed‑policy assumption, suggesting possible gains in sample efficiency and formal constraints. The authors also note that relaxing the fixed‑policy assumption allows the linear potential theory framework to extend naturally to nonlinear cases.

By Christopher Connolly
arXiv Machine Learning
Jul 1

Automated Discovery of Operable Dynamics from Videos

arXiv:2410. 11894v3 Announce Type: replace-cross Abstract: Dynamical systems form the foundation of scientific discovery, traditionally modeled with predefined state variables such as the angle and angular velocity, and differential equations such as the equation of motion for a single pendulum.

By Kuang Huang, Dong Heon Cho, Boyuan Chen