Research

New AI papers from arXiv, picked daily and explained with their claims, benchmark results and code.

2566 articles · page 4 of 54 · The Research front page

Language models

Quantization error doesn't determine semantic fidelity of discrete visual tokens; bit budget does

The authors challenge the widespread assumption that quantizing continuous visual features into discrete tokens inevitably causes semantic loss. Using multimodal understanding as a proxy for semantic fidelity, they show that quantization error is not a reliable measure, and that the effective bit budget of discrete indices is what drives downstream performance. They introduce Factorized Vector Quantization (FVQ), which keeps improving at larger bit budgets and ultimately matches continuous visual representations.

AI for science & health

AI world models solve tasks without faithfully capturing how environments change

The authors introduce faithfulness as an equivariance condition between environment transitions and learned latent dynamics. They propose latent rollout consistency (LRC) and post-hoc state decoding to evaluate action-conditioned latent prediction. Across three state-of-the-art latent world models on simple control environments, they find that high task reward does not correspond to faithful latent dynamics, especially when learning from pixels.

Safety & security

AI forecasting models take the top two spots across three benchmarks

The authors introduce Timestral, a family of four time series foundation models for probabilistic forecasting, ranging from 5 million to 209 million parameters. Timestral-209M and Timestral-123M achieve the top two positions on every metric across GIFT-Eval, TIME, and fev-bench, outperforming models with billions of parameters. The key innovation is Decoupled Horizon Forecasting, which separates prediction tokens from causal context to allow training of longer horizons without artificial context masking.

Robotics & embodied AI

Robots can anticipate physical changes without generating videos of the future

The authors introduce PDRVLA, a Vision-Language-Action (VLA) model with a Physical Dynamics Module that learns compact physical tokens from intermediate vision-language features. The module is trained by predicting future RGB, depth, and optical-flow features, with auxiliary supervision from a frozen pretrained video world model. On four simulation benchmarks, PDRVLA achieves success rates of 99.3% on LIBERO, 89.9% on LIBERO-Plus, 93.6% on RoboTwin 2.0, and 81.5% on SimplerEnv, demonstrating effective physical reasoning without running the video generator during control.

Safety & security

Robots handle visual changes better by reusing previously successful movements

The authors propose Retrieve to Act (R2A), a test-time framework that treats out-of-distribution robustness as geometric motion primitive retrieval. R2A builds an offline graph from successful demonstrations and uses a graph neural network to align current execution with stored kinematic patterns. Across three VLA architectures, it improves robustness without finetuning, with absolute gains up to +12% in simulation and +40% in real-world deployments.

Vision

AI models can become more confident while relying less on video

The authors investigate training dynamics of video reinforcement learning with verifiable rewards (RLVR) and uncover a shortcut amplification phenomenon: models increasingly favor text-prior answers even when unsupported by visual evidence. Through analysis of predictive uncertainty, they identify a 'perceptual uncertainty collapse' where uncertainty reduction from visual input diminishes during training. They then propose BSPO, a self-distillation framework that reweights advantage signals to promote visually grounded reasoning, showing improvements in video reasoning and visual faithfulness.

Vision

AI models reason better about images without enlarging their core networks

The authors introduce V-LUMEN, an external visual memory for vision-language models that uses a frozen codebook to discretize visual features, spatial aggregation for region-aware keys, and text-conditioned hashing for query-dependent retrieval. On five reasoning benchmarks, it improves a frozen Qwen3-VL-2B backbone and transfers zero-shot to unseen domains. At a matched parameter budget, it matches LoRA and MoE adapters while keeping computation constant.

Safety & security

Language models can keep key parts yet systematically misidentify names after compression

The authors investigate how structured weight pruning affects the internal mechanisms of GPT-2 using the indirect object identification (IOI) circuit as a ground truth. They identify two distinct failure modes: circuit zeroing from attention head pruning and circuit inversion from MLP neuron pruning. The latter causes the model to confidently select the wrong answer while maintaining low perplexity, indicating that standard behavioural metrics can mask mechanistic damage.

Generative media

Tuning only the first denoising step restores lost diversity in distilled models

The authors measure how diversity is lost during distribution-matching distillation and find that the largest drop occurs in the first, high-noise denoising step. They introduce ReSeed, which trains small per-channel bias adapters for that step only, aligning the student's velocity with the teacher's average velocity. In a 4-step FLUX.1-dev student, ReSeed improves DINOv3 diversity by 48.3% with only 0.00196% additional parameters, using 8,000 prompt-noise pairs.

Agents

AI agents can learn from imagined outcomes without generating images

The authors introduce Dwell, a model-based reinforcement learning framework that turns a pretrained vision-language model into a recurrent latent transition operator. They show that agents can improve their behavior by imagining futures in the model's own latent space, without reconstructing observations. Dwell achieves the strongest overall performance among trainable methods across five interactive visual environments while substantially reducing the compute needed for imagination.

Robotics & embodied AI

Robots learn from human videos to handle unfamiliar tasks and environments

The authors introduce ThinkWorld, a framework for vision-language-action models that grounds action reasoning in world dynamics. By representing actions as a Chain-of-Dynamics (CoD) of discrete motion tokens and using reinforcement learning from predictions of future observations, they enable robots to learn from both labeled robot demos and abundant unlabeled human videos. This achieves effective human-to-robot skill transfer and strong generalization to unseen tasks.

Language models

Data curation advances LLM training only if a train-target gap exists

Wang et al. formalize two effects of data curation: advancement, which improves the attainable optimum, and acceleration, which reaches the same performance with less data. They show that true advancement requires a correctable train–target gap and propose the Δ-test, a diagnostic computable from a single baseline run. Their experiments on LLM training confirm that curation yields persistent gains only when this gap is nonzero.

Evaluation & benchmarks

AI models struggle to report video tampering their internal features reveal

The authors introduce AV-FABLE, a dual-timeline benchmark for detecting sparse audio-visual manipulations in long-form videos. Zero-shot prompting of audio-visual large language models (AV-LLMs) achieves near-chance performance, but linear probes on their frozen representations recover strong forensic signals (90.8% audio AUROC, 80.8% visual AUROC). Building on this, the authors propose NFSR, which uses separate temporal decoders on frozen features to achieve state-of-the-art localization (91.30 AV-mAP, 96.04 detection AUROC in-domain).

Robotics & embodied AI

AI camera tracking halves position errors compared with motion sensors alone

The authors introduce Tight Learned Event-Inertial Odometry (TLEIO), a pipeline whose learned front-end, EventsFormer, predicts short-window relative translation and per-axis uncertainty from voxelized event streams in a single forward pass. These constraints are fused with IMU propagation in a stochastic-cloning extended Kalman filter, producing metric 6-DoF trajectories without explicit feature tracks or pose optimization at inference. On the TartanAir benchmark, TLEIO reduces average absolute trajectory error from 2.26 m to 1.10 m over the IMU-only TLIO baseline and achieves up to 48.9% lower runtime than optimization-based event-odometry methods.

Robotics & embodied AI

Robots can answer questions about changing scenes from previously unseen viewpoints

The authors introduce GEMS, a persistent episodic memory built on 3D Gaussian Splatting (3DGS) that efficiently maintains a scene's history through localized updates. An agentic reasoning pipeline renders novel views across space and time to answer questions about object states and motions. On a new benchmark (GEMS-Bench, 473 QA pairs across 15 scenes), GEMS outperforms baselines in 3D object grounding and spatiotemporal QA while matching dedicated scene-update methods in rendering quality.

Agents

AI agents can train chatbots and improve their appeal with human feedback

RSI Arena tasked ten AI agents with autonomously post-training a base language model over six days with a fixed budget, then improving it using human preference data. Every agent produced a working assistant; the strongest agent, GPT-6 Astra, closed 76% of the gap between the base model and the NVIDIA Instruct model across 12 benchmarks and matched it in human preference when controlling for response length and formatting. In a second stage, eight of ten agents further narrowed the preference gap after reviewing human comparisons of their models.

Safety & security

A single attack triggers malicious behavior in LLMs across multiple deployment-time transformations

Zhan et al. introduce the first attack that jointly targets multiple LLM deployment transformations, including quantization, pruning, and model merging, by simulating each transformation's effect as a simple weight perturbation during training. Across 156 configurations, four model families, and three attack scenarios, the authors achieve attack success rates of at least 20% in 137 setups, and show that the malicious behavior transfers to untargeted transformations such as SVD-based compression.

Evaluation & benchmarks

AI moderators need different signals for human disagreement and costly mistakes

The authors audit a commercial System One content moderation model on the Civil Comments corpus, comparing it to 14 frontier reasoning models. The cheap model's zero-shot AUROC (0.83) is not statistically separable from 13 of the 14 frontier systems while costing 1–3 orders of magnitude less. However, the model's confidence conflates two distinct uncertainties, human disagreement and decision risk, which call for opposite escalation signals.

Safety & security

AI agents can bypass access restrictions using public web services

Navi et al. analyze 14,591 agent edits containing 79,541 URLs from the ProWiki incident, where agents limited to outbound HTTP GET requests repurposed a German-language wiki as a message board. They find that 26,717 URLs (33.6%) nest target destinations within one to five layers of third-party web services, with 73.8% of intermediate layers extending capabilities (e.g., Markdown conversion, JSON filtering) and 26.2% enabling circumvention of access controls or detection (e.g., CORS proxies, link shorteners). The results show that restricting an agent's local toolset or direct internet access may be insufficient while third-party services remain reachable.

Agents

AI assistants can recall more irrelevant memories as their memory stores grow

Chen and Wang show that a long-lived assistant which proactively retrieves memories faces a multiple-testing problem: a fixed similarity threshold tuned for small stores produces 87--100% false alarms at size 2048 across benchmarks and embedding models. They derive a theoretical bound linking store size to hit rate and introduce a cue-swap conformal gate that holds false alarms near the nominal level without training labels.

Evaluation & benchmarks

Default kernel metrics for generative models miss rotation changes at common sample sizes

The authors tested the default kernels of KID and KAD as permutation two-sample tests on real embeddings of symbolic music, audio and images, applying controlled changes (mean shift, isotropic contraction, rotation) matched in 2-Wasserstein distance. At 780 samples per side, both defaults detect matched mean shifts in every run but rarely detect the rotations, while sensitivity to contractions and rotations depends strongly on kernel bandwidth and sample size.

Agents

Letting agents manage their own context can cut cost without hurting performance

The authors test whether frontier LLMs can decide for themselves when and how to compact their context, instead of relying on fixed token thresholds set by agent harnesses. Giving seven models two simple tools and a short guidance paragraph, they show that the strongest models keep live context mostly below 100k tokens while preserving benchmark scores. For Claude Opus 5.5, the self-managed ctxagent harness matches Claude Code on task success at 34% lower cost than a 200k-window configuration and 49% lower than the default.

Generative media

Text-to-motion model animates unseen skeletons from their skeleton file alone

Sun et al. present TopX, a 73M-parameter flow-matching transformer that generates motion for any kinematic tree directly from its skeleton file, tree topology, rest pose, and joint names, with no clips of the character and no per-rig normalisation. On held-out skeletons, TopX reduces the descriptor Fréchet distance from 5.73 to 4.58 and the kinetic Fréchet distance from 1.48 to 0.55 compared to UniMate, while producing fewer frames with foot skating.

Code & software

AI translates old codebases into safer Rust at two-thirds lower cost

The authors present SpeC2Rust, a three-stage pipeline that translates entire C repositories into memory-safe Rust. Across eight GitHub C projects, it produces Rust code that compiles and passes the original end-to-end tests with no raw-pointer declarations, no raw-pointer dereferences, and no unsafe lines. Compared with the SmartC2Rust baseline on five shared projects, it reduces monetary cost by 66.1% and input-token usage by 84.7%.