EBT-Policy: Energy Unlocks Emergent Physical Reasoning Capabilities
Authors: name: Travis Davies, name: Yiqi Huang, name: Alexi Gladstone, name: Yunxin Liu, name: Xiang Chen, name: Heng Ji, name: Huxian Liu, name: Luhui Hu

Implicit policies parameterized by generative models, such as Diffusion
Policy, have become the standard for policy learning and Vision-Language-Action
(VLA) models in robotics. However, these approaches often suffer from high
computational cost, exposure bias, and unstable inference dynamics, which lead
to divergence under distribution shifts. Energy-Based Models (EBMs) address
these issues by learning energy landscapes end-to-end and modeling equilibrium
dynamics, offering improved robustness and reduced exposure bias. Yet, policies
parameterized by EBMs have historically struggled to scale effectively. Recent
work on Energy-Based Transformers (EBTs) demonstrates the scalability of EBMs
to high-dimensional spaces, but their potential for solving core challenges in
physically embodied models remains underexplored. We introduce a new
energy-based architecture, EBT-Policy, that solves core issues in robotic and
real-world settings. Across simulated and real-world tasks, EBT-Policy
consistently outperforms diffusion-based policies, while requiring less
training and inference computation. Remarkably, on some tasks it converges
within just two inference steps, a 50x reduction compared to Diffusion Policy's
100. Moreover, EBT-Policy exhibits emergent capabilities not seen in prior
models, such as zero-shot recovery from failed action sequences using only
behavior cloning and without explicit retry training. By leveraging its scalar
energy for uncertainty-aware inference and dynamic compute allocation,
EBT-Policy offers a promising path toward robust, generalizable robot behavior
under distribution shifts.