WorldString: Actionable World Representation via Neural Architecture for Object State Modeling
This paper proposes WorldString, a neural architecture designed to model the state manifold of real-world objects by learning from point clouds or RGB-D video streams. Unlike prior approaches that rely on video generation or dynamic scene reconstruction, WorldString explicitly models object action states in a unified, principled framework. It is positioned as a foundational building block for physical world models, functioning as a versatile digital twin. Its fully differentiable structure is intended to enable integration with policy learning and neural dynamics.
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GRASP: Gradient-based Planning for World Models at Longer Horizons
Researchers from Berkeley, Meta, and collaborators introduce GRASP, a gradient-based planner designed to make long-horizon planning with learned world models more robust. The method addresses three core failure modes: ill-conditioned computation graphs from backpropagation through time, non-greedy loss landscapes with many local minima, and brittle gradients through high-dimensional vision models. GRASP lifts trajectory optimization into virtual states for parallel optimization across time, injects stochasticity into state iterates for exploration, and reshapes gradients to avoid problematic state-input gradient paths. The work is positioned in the context of scaling world models toward general-purpose simulators usable for control and planning.
Looped World Models introduce iterative latent depth as a new scaling axis for world simulation
A new arXiv preprint introduces Looped World Models (LoopWM), a parameter-shared transformer architecture that iteratively refines latent environment states to achieve up to 100x parameter efficiency over conventional world models. The approach uses adaptive computation to scale depth dynamically per prediction step, addressing the tension between long-horizon simulation fidelity and deployment cost. The authors position iterative latent depth as a new scaling axis orthogonal to model size and training data.
Video generation models as world simulators
OpenAI introduces Sora, a large-scale text-conditional video diffusion model built on a transformer architecture that operates on spacetime patches of video and image latent codes. The model is trained jointly on videos and images of variable durations, resolutions, and aspect ratios. Sora can generate up to one minute of high-fidelity video and OpenAI frames scaling video generation as a path toward general-purpose physical world simulators.
AHA-WAM: Asynchronous world-action modeling with temporal decoupling for robot manipulation
AHA-WAM introduces a dual Diffusion Transformer architecture that decouples world prediction (low-frequency) from action execution (high-frequency) in robot manipulation policies, addressing the inefficiency of existing world-action models that force both branches to operate at the same temporal resolution. The system uses a rolling key-value memory video DiT as a long-horizon scene planner and a fast action DiT that queries layerwise latent context via joint attention, with Observation-Guided Video-Context Routing enabling asynchronous execution. On RoboTwin benchmarks, AHA-WAM achieves 92.80% average success and 78.3% on real-world tasks at 24.17 Hz, a 4.59x speedup over Fast-WAM, without robot-data pretraining.
SpatialWorld benchmark evaluates interactive spatial reasoning of multimodal agents in real-world tasks
Researchers introduce SpatialWorld, a benchmark for evaluating interactive spatial understanding of multimodal agents across 760 human-annotated tasks spanning household, travel, and social domains. The benchmark integrates eight simulation backends under a shared protocol, requiring agents to operate under vision-only partial observability with egocentric inputs. Evaluation of 15 agents reveals that even the strongest model, GPT-5, achieves only 17.4% task success rate, exposing significant gaps in active exploration and long-horizon planning. The work highlights a mismatch between task success and execution efficiency as a key bottleneck for spatial agents.
Episodic Context and Persistent 3D World Models Enable Curiosity-Driven Exploration in Photorealistic Environments
This paper addresses the failure modes of curiosity-driven RL in complex 3D environments, where agents revisit forgotten states and get trapped in local loops due to lacking spatial persistence and episodic memory. The authors combine an online 3D reconstruction as a persistent world model with a sequence-model policy over RGB observations to maintain episodic trajectory context. Trained purely via intrinsic curiosity on HM3D, the agent outperforms RL-based active mapping baselines and zero-shot generalizes to Gibson and AI-generated environments. The approach also enables efficient downstream task adaptation for apple picking and image-goal navigation.
STORM: Internalized Spatial-Temporal Reasoning for Video-Language Models via Latent Trajectories
STORMS is a two-stage training framework that teaches large vision-language models to perform spatial-temporal video reasoning through bounded continuous latent trajectories rather than explicit textual chain-of-thought, keyframe selection, or external tool use. In Stage I, latent tokens are aligned with thought-video representations derived from generated videos; in Stage II, answer-only supervision internalizes the reasoning process. At inference time, no video regeneration or frame reinsertion is required, reducing latency and engineering complexity. Evaluations on VideoMME, MVBench, TempCompass, and MMVU show improved accuracy with substantially lower inference overhead versus tool-based pipelines.
Qwen-VLA: Unified Vision-Language-Action Model Across Robot Tasks, Environments, and Embodiments
Alibaba's Qwen team presents Qwen-VLA, a unified embodied foundation model that extends the Qwen vision-language stack to continuous action and trajectory generation via a DiT-based action decoder. The model is jointly pretrained on diverse data spanning manipulation trajectories, egocentric demonstrations, synthetic simulation, and navigation data, with embodiment-aware prompt conditioning to support multiple robot platforms. A unified action-and-trajectory prediction framework covers manipulation, navigation, and trajectory prediction tasks. Benchmarks show strong results: 97.9% on LIBERO, 73.7% on Simpler-WidowX, 69.0% OSR on R2R navigation, and 76.9% average OOD success in real-world ALOHA experiments.