Computation and Language
Does the Linguistic Register of Thinking Matter? Wenyan as a Compact Reasoning Register for Chinese LLMs
Minghan Li and Guodong Zhou
Visible
reasoning traces of Chinese
reasoning-oriented LLMs are typically written in modern vernacular Chinese, which may be verbose under limited decoding budgets. We ask whether the linguistic register of
reasoning can be used to improve efficiency. We propose Wenyan Thinking, which emits intermediate
reasoning in Classical Chinese (wenyanwen) while retaining a short direct-answer output. Starting from modern-Chinese
reasoning traces, we rewrite only the
reasoning field into wenyan and fine-tune Qwen3-4B-Thinking-2507 on the rewritten supervision. To distinguish register shift from generic compression, we construct a compact modern-Chinese control using the same source data, teacher family, base model, and SFT recipe. Across budget-sensitive evaluations on MMLU-ProX-Lite-ZH, CEVAL, and AGIEval-CN, Wenyan Thinking substantially reduces
reasoning length and missing-answer rates under constrained decoding. Compact rewriting explains much of the efficiency gain, while wenyan consistently outperforms the compact modern-Chinese control on the primary
benchmark and remains competitive across the additional
benchmarks. These results identify linguistic register as a practical design axis for efficient visible
reasoning in Chinese LLMs.
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Analysis of PDEs
Asymptotic stability and Rayleigh-Taylor instability of stratified states for the three-dimensional rotating primitive equations with gravity
Yanlong Fan, Fengjie Luo, Yiqiu Mao et al. (+1 more)
We study the 3D rotating primitive equations with
gravity in a horizontally periodic channel, with viscous horizontal velocity and no density
diffusion. For every Coriolis parameter, stably stratified
equilibria are asymptotically stable. Small compatible \(H^4\) perturbations yield global classical solutions with uniform \(H^4\) bounds. The oscillatory density and velocity decay like \((1+t)^{-1}\); the density converges at the same rate to a stratified profile, its horizontal mean faster. For small data, the limit profile is the decreasing vertical rearrangement of the initial density, the unique potential-energy minimizer among rearrangements, independent of rotation, viscosity, and initial velocity. Kinetic plus available potential energy is dissipated exactly by viscosity and decays like \((1+t)^{-2}\), and each fluid particle settles where the limit density equals its own. These rates are optimal for every rotation rate. The linearized problem has real, slowly decaying normal modes, viscously overdamped high-vertical-wavenumber internal
gravity waves, whose small solutions show the \(H^r\) density rates \((1+t)^{-(1-r/4)}\), \(0\le r<4\), pressure rate \((1+t)^{-1}\), and energy rate \((1+t)^{-2}\) cannot be improved uniformly for small data. Key difficulties are the loss of a horizontal derivative in the vertical velocity, the failure of \(H^1(\mathbb T^2)\subset L^\infty\), and rotation-induced coupling of divergent and vortical motion, controlled at top order by a positive power of the initial low-order energy. If the stratification is unstable somewhere, every horizontal mode is linearly unstable with real growth rates and the
equilibrium is nonlinearly unstable; rotation strictly lowers each growth rate, with an explicit Taylor-number bound depending on the horizontal wavelength, but leaves their supremum unchanged.
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All authors Yanlong Fan, Fengjie Luo, Yiqiu Mao, Quan Wang
Solar and Stellar Astrophysics
High-Frequency Transverse Waves in Chromospheric Fibrils Revealed by DKIST
Qifan Dong, Xiaoli Yan, Zhike Xue et al. (+4 more)
Chromospheric fibrils are ubiquitous dynamical structures that can support magnetohydrodynamic waves and may contribute to energy transport in the solar atmosphere. Using high-resolution observations from the Visible Broadband Imager (VBI) onboard the Daniel K. Inouye Solar
Telescope (DKIST), we investigate transverse oscillations of H$\alpha$ fibrils. Our observations encompass both quiet-Sun and active regions. The results reveal that high-frequency transverse oscillations are highly prevalent in fibrils across different
magnetic environments. The detected oscillations exhibit typical periods of 56 $\pm$ 49 s, displacement amplitudes of 37 $\pm$ 25 km, velocity amplitudes of 6 $\pm$ 4 km\,s$^{-1}$, and phase velocities of 21 $\pm$ 13 km\,s$^{-1}$. Under typical chromospheric conditions, the estimated wave energy flux ranges from 20 to 200 W\,m$^{-2}$. The characteristics of these transverse oscillations are consistent with those of Alfvénic kink-mode waves. Our results reveal the existence of the high-frequency, small-amplitude transverse waves in chromospheric fibrils and providing new constraints on their contribution to the chromospheric and coronal heating.
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All authors Qifan Dong, Xiaoli Yan, Zhike Xue, Liheng Yang, Jincheng Wang, Yadan Duan, Zhe Xu
Machine Learning
ProtModernBERT: Compute-Efficient Protein Language Modeling
Alberto Martínez, Natalia Flechas Manrique, Llorenç Espinosa-Portalés et al. (+1 more)
Large
protein language models provide a powerful framework for learning sequence-function relationships and guiding experimental design. However, architectural improvements are underexplored, especially in low-compute regimes of relevance for resource-constrained research laboratories. We show that the training cost for encoder-only
transformer architectures can be reduced by leveraging modern architectural refinements, offering an encouraging performance / compute-efficiency trade-off. We introduce ProtModernBERT, a modernized BERT-style model pre-trained on amino acid sequences, and compare it with ProtBert, Amplify, and ESM2 across a set of supervised structural tasks -encompassing secondary structure prediction, disorder prediction, and subcellular localization- and ProteinGym's zero-shot functional
benchmark. We find that ProtModernBERT matches or closely tracks the performance of Amplify-120M and ProtBert with up to 80-90% reduction in pre-training FLOPs, and narrows the gap to ESM2 when controlling for pre-training. Our analysis using a cluster-based validation protocol for hyperparameter selection and randomly initialized models disentangles the contributions of architecture and data, showing that modern components provide stronger inductive biases that are more consequential than parameter count in low-compute regimes.
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All authors Alberto Martínez, Natalia Flechas Manrique, Llorenç Espinosa-Portalés, Luc Andrea
Probability
Gaussian approximation for the integrated intensity of counting processes: application to Hawkes processes
Benjamin Massat
In this paper, we establish quantitative central limit
theorems for the integrated fluctuations of the intensity of a counting process. Building on the work of Coutin and using the Clark-Ocone formula, we first derive a general upper bound on the Wasserstein distance between a Gaussian random variable and the normalized integral of the centered intensity. We then apply this result to subcritical linear Hawkes processes. In this setting, we prove that the integrated fluctuations of the intensity converge in distribution to a centered Gaussian random variable, with a convergence rate governed by the tail behavior of the resolvent associated with the underlying Volterra equation.
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Quantum Physics
Void-Free Through-Glass Vias for Multilayer Surface-Electrode Ion Traps
Eike Iseke, Jacob Stupp, Friederike Giebel et al. (+6 more)
Through-substrate interconnects are a key technology for scaling surface-electrode ion traps (SEITs) toward large electrode counts and complex architectures. Dielectric substrates such as fused silica offer superior RF performance compared to silicon, but the reliable fabrication of void-free through-glass vias (TGVs) remains challenging. In this work, we demonstrate a SEIT fabricated on a fused silica substrate incorporating TGVs. The via-holes are formed using Selective
Laser-Induced Etching and subsequently metallized with gold by electroplating. A patent-pending geometry-assisted bottom-up plating approach enables void-free filling using constant-current electroplating without electrolyte additives or pulsed deposition schemes. Electrical characterization across multiple wafers confirms a TGV-level yield above 98.8 %, demonstrating the robustness and reproducibility of the developed TGV technology. The TGVs are combined with multilayer SEIT fabrication, enabling vertical signal routing to all electrodes while maintaining an unaffected trapping surface without wire bonds. To interface the trap with external control electronics, a glass interposer providing signal fan-out to a larger pitch is designed and fabricated. The trap chip and the interposer are integrated using thermocompression bonding, forming a compact chip-to-chip assembly. The presented technology demonstrates the first fully integrated multilayer SEIT on fused silica incorporating void-free TGVs.
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All authors Eike Iseke, Jacob Stupp, Friederike Giebel, Nila Krishnakumar, Konstantin Thronberens, Nora D. Stahr, Md. Masum Billah, Marlon Kuhn, Christian Ospelkaus
Computation and Language
MakSafe: A Spatiotemporal Semantic Framework for Formal Specification and Compliance Checking of Road Vehicle Safety Rules
Maksym Labzhaniia, Julien Deantoni, Marie-Agnès Peraldi-Frati et al. (+1 more)
Scenario-based validation is essential for automated road vehicles but cannot cover the full variability of openworld traffic. We present MakSafe, a formal spatiotemporal framework for specifying and checking road vehicle safety rules through semantic zones, action-based forecasting, and trace-tree
reasoning, avoiding uniform time discretization. We formalize the road network, vehicle states, and occupancy zones, then build executable rules for front-vehicle identification and timeto-collision (TTC) verification. The evaluation combines a tracedependent case study with a scalability
benchmark over traffic density (N ), horizon (H), and branch factor (B). MakSafe yields branch-specific verdicts, deriving safe and unsafe outcomes from the same initial scene, and re-evaluates a scenario after a control update. A single rule check stays well below a millisecond across the reported sweep, and longer horizons slow the TTC check.
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All authors Maksym Labzhaniia, Julien Deantoni, Marie-Agnès Peraldi-Frati, Frédéric Mallet
Computer Vision
Object Pose from 2-D to 3-D Point and Line Correspondences
Thai Quynh Phong, Radu Horaud, Adnan Yassine et al. (+1 more)
In this paper we present a method for optimally estimating the rotation and translation between a camera and a 3-D object from point and/or line correspondences. First we devise an error function and second we show how to minimize this error function. The quadratic nature of this function is made possible by representing rotation and translation with a dual number quaternion. We provide a detailed account of the computational aspects of a trust-region optimization method. This method compares favourably with Newton's method which has extensively been used to solve the problem at hand, with Faugeras-Toscani linear method [6] for calibrating a camera, and with the Levenberg-Marquardt non-linear optimization method. Finally we present some experimental results which demonstrate the robustness of our method with respect to image noise and matching errors.
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All authors Thai Quynh Phong, Radu Horaud, Adnan Yassine, Pham Dinh Tao
Multiagent Systems
Exact Cut Complexity of Equal-Length Proportional Cake Cutting
Yasushi Kawase, Bodhayan Roy and Mohammad Azharuddin Sanpui
We study proportional cake cutting under an equal-length constraint, where each of $n$
agents must receive a bundle of length exactly $1/n$ that is worth at least $1/n$ to that
agent. Our main result determines the exact worst-case number of cuts needed to guarantee such an allocation, namely $2n-2$ for every $n$. This improves on the previously known quadratic upper bound. The proof combines the constrained necklace-splitting
theorem with a recursive assignment argument based on Hall's
theorem. The same bound extends to the stronger requirement of envy-freeness when $n$ is a
prime power, and an $O(n^{1.525})$ upper bound holds for arbitrary $n$. We then ask whether such allocations can be computed. We first show that no deterministic protocol in the Robertson–Webb model terminates after finitely many queries on every instance and always returns an exact equal-length proportional allocation, even for two
agents with identical valuations. For every $\varepsilon>0$, however, $O(n^2/\varepsilon)$ queries suffice to produce an allocation in which every
agent receives a bundle of length exactly $1/n$ and value at least $1/n-\varepsilon$, again using at most $2n-2$ cuts. Finally, we augment the Robertson–Webb model with two-knife queries. We show that recursive balanced halving attains the optimal bound of $2n-2$ cuts when $n$ is a power of two. For arbitrary $n$, we give a procedure using $O(n\log n)$ cuts.
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Neural and Evolutionary Computing
Controlling the latency in temporal coded spiking models for neuromorphic datasets
Alban Gattepaille and Alexandre Muzy
Exploiting temporal information in
datasets with high temporal dependencies (such as spoken keyword recognition) by spiking models is still an open problem. Promising frameworks include Time-To-First coding (TTFS) and the inclusion of synaptic delays into learning. In TTFS,
neurons are forced to spike at most once, forcing the network to found its learning on the spiking times of
neurons rather than their spiking rate. Some models use the TTFS framework to directly compute the spiking time of Integrate-and-Fire (IF) or Leaky Integrate-and-Fire (LIF)
neurons. However, most models built in the TTFS framework have not been tested against
datasets containing temporal information. Little is known about the latency of these models on temporal
datasets, where the latency is the time taken by the network to correctly classify a sample. In this work, we study the behaviour of Delay Neural Networks (DeNN) models, i.e. models that directly compute the spiking time of
neurons by bypassing the membrane potential and thresholding mechanisms of spiking
neurons. We show how to analytically control their latency, and empirically study the latency-accuracy tradeoff in a dynamic temporal
dataset.
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Machine Learning
What Happens to the Goal? Distinct Failures of Policy Alignment in Goal Misgeneralization
Julia Barth, Armin Sommer, Kunvar Thaman et al. (+1 more)
Goal misgeneralization is a common failure mode in which an
agent behaves competently out of distribution but does not pursue the intended goal. However, we still have a weak understanding of what happens to the intended goal in misgeneralizing
agents. Across three Procgen environments and five
robot tasks, we find three distinct forms of policy-goal misalignment: (1) functional target substitution, where behavior follows an alternative goal, (2) a policy shortcut, where behavior follows a learned action strategy, and (3) cue competition between intended and proxy goal cues. We distinguish these regimes by tracing where goal information remains available internally, how strongly it influences the policy, and what role it plays in action selection, and find that the goal is lost at different depths. Where the goal reaches the decision, as in cue competition, steering redirects the policy to the goal's location, raising intended-goal reach from 16.0% to 95.3%. Where it reaches the policy but not the decision, only new downstream wiring recovers goal reach, from 31.6% to 84.3% in the environment with the action shortcut. Where it is inert, neither works. Our results show that goal misgeneralization is not a single failure of goal representation, but distinct failures of policy
alignment at different depths, tightly connected to which recovery works.
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All authors Julia Barth, Armin Sommer, Kunvar Thaman, Jannik Schilling
Neural and Evolutionary Computing
Design and Analysis of Temporal Representations in Neural Networks
Alban Colas-Gattepaille and Alexandre Muzy
The ability to represent temporal information is often hypothesized to underlie the efficiency and learning capabilities of biological neural networks. This motivates the development of spiking neural networks. However, it remains unclear how temporal information is actually represented in neural networks and how different forms of temporal representation affect performance and computational efficiency. We introduce the notion of the degree of temporal representation of a neural network, defined by whether its constituent functions (activation, learning, encoding, and decoding) explicitly manipulate time as a computational variable. This perspective yields a continuum ranging from non-temporal representations, where time does not explicitly appear as a computational variable in the network functions, to fully temporal representations, where computations explicitly operate on temporal variables. Using a fixed deep architecture, we compare different encoding, activation mechanisms and decoding with increasing temporal expressiveness: non-temporal weighted-sum activations used in usual artificial neural networks, non-temporal binary spiking activations used in spiking neural networks, and spike-time-based activations used in delay neural networks. Experiments on event-based
datasets show that increasing the degree of temporal representation improves both performance and computational efficiency, allowing state-of-the-art performances on the Google
Speech Commands
dataset. We further analyze how temporal representations induce distinct forward and backward computational trajectories, leading to gradients that depend explicitly on the history of event times.
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Computer Vision
A Diagnostic Study of World-Space Human Recovery Under High Camera Dynamics
Hao-Jen Chien, Wei-Lun Chao and Yu-Lun Liu
Monocular world-space human recovery methods excel on current
benchmarks, but these rarely include fast camera motion. We introduce the K-Pop stress test, broadcast dance
videos that combine fast, large camera motion with dense multi-person choreography. Leading methods produce plausible per-frame meshes on these
videos, yet their world-space trajectories drift far from the performers' stage positions. Through a systematic diagnosis, we show that the camera and human estimates each remain self-consistent, and that the drift appears when they are combined at mismatched scales. Each is recovered at its own scale, so a mismatch between the two can turn camera motion into human drift that grows with camera displacement and becomes severe in broadcast dance
videos. We derive a closed-form correction that estimates this mismatch and applies one scale to all performers, removing the drift while keeping their relative positions in one shared world frame. It requires no retraining and works with existing backends. Combined with physical constraints, the correction yields stable world-space reconstruction for choreography modeling, scene editing, data generation, and virtual reshooting. Project page: https://chien90190.github.io/worldhmr-fastcam-website/
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Computer Vision
Zhixin Cai, Ruoqi Yuan, Xinchen Yang et al. (+4 more)
Video large
language models (
Video LLMs) often generate responses unsupported by the input
video. Contrastive decoding (CD) can mitigate these
hallucinations, but its effectiveness depends on how the negative branch weakens visual evidence. Existing methods rely on predefined perturbations or masking guided by question reconstruction, offering limited control over the model's visual reliance during answer generation. We introduce
Attention-guided Representation Perturbation for Contrastive Decoding (ARP-CD), a training-free framework for constructing contrastive negatives directly in representation space. ARP-CD uses the
attention mass assigned to visual
tokens at the answer-prediction position to guide bounded gradient updates of the
language model's input visual hidden states. These updates reduce visual
attention and produce a negative input, whose predictions are contrasted with those of the original branch throughout generation. Experiments across four
Video LLMs and four
benchmarks show that ARP-CD outperforms representative training-free baselines in most model–
benchmark settings, reducing
hallucinations while improving general
video understanding. Further analyses show that
attention-guided perturbation directions improve negative quality and that the resulting negatives provide effective contrastive references for correcting the original predictions.
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All authors Zhixin Cai, Ruoqi Yuan, Xinchen Yang, Zhuofan Chen, Jun Bai, Chuantao Yin, Wenge Rong
Strongly Correlated Electrons
Role of Gd 5d-Au 5d hybridization for the magnetic properties of Au-Al-Gd quasicrystal approximants
Goro Nozue, Hidenori Fujiwara, Satoru Hamamoto et al. (+18 more)
We have studied the electronic states of
magnetic Au-Al-Gd quasicrystal approximants, which exhibit different
magnetic ground states at low temperatures, by orbital-selective soft and hard x-ray electron spectroscopies in the paramagnetic phase. Our results reveal that the valence electronic states vary among the Au-Al-Gd approximants with different
magnetic ground states, whereas the Gd 4f electrons are localized in all of them. In particular, we find that the Gd 5d states are hybridized with the Au 5d states around the Fermi level, providing information about a local pathway for the intersite exchange interaction between the localized Gd 4f electrons. This hybridization strength varies among these samples. Our findings bring an orbital-resolved microscopic picture to the magnetism of rare-earth-based quasicrystals and approximants.
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All authors Goro Nozue, Hidenori Fujiwara, Satoru Hamamoto, Yuto Torii, Mai Sakaguchi, Sho Nakajima, Takuya D. Nakamura, Nonoka U. Sakamoto, Takayuki Kiss, Masaki Oura, Akira Yasui, Kotaro Higashi, Naomi Kawamura, Kojiro Mimura, Arata Tanaka, Asuka Ishikawa, Farid Labib, Shintaro Suzuki, Takafumi D. Yamamoto, Ryuji Tamura, Akira Sekiyama
Computer Vision
Generative World Simulation with DAO and JING
XGEN Team: Guohao Cai, Haoxuan Che, Frank Fan et al. (+15 more)
We present a Generative World Simulation framework that couples persistent shared world state with continuous first-person audiovisual generation. The framework integrates DAO, a computable world engine, and JING, an Egocentric Interactive Experience Model, to support sustained interaction for humans and
agents. DAO maintains the states of characters, objects, and spaces and their relationships, advancing the world according to interaction rules and world time while preserving the consequences of past actions. From this evolving state, DAO derives observer-specific conditions for JING, which combines these conditions with character, object, and scene references, observation history, and current actions to generate each observer's audiovisual experience. Users can explore environments, manipulate objects, and communicate with characters through viewpoint control and text instructions, with their actions shaping both the shared state and subsequent experiences. By connecting world-state
evolution with experience generation in a continuous interaction loop, the framework offers an approach to building interactive worlds that retain their history, evolve through action, and persist beyond any individual observer.
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All authors XGEN Team: Guohao Cai, Haoxuan Che, Frank Fan, Chenran Huang, Junjia Huang, Jiayi Jiang, Yanheng Li, Leon Liu, Shaoteng Liu, Xi Liu, Feng Nie, Zhefan Rao, An Wang, Hanwen Wang, Pengxiang Yan, Jieming Yu, Qian Zha, Wentao Zheng
Machine Learning
TimeRSI: Towards Self-Improved Agentic Deployment for Time-Series Foundation Models
Haoxin Liu, Deqing Fu, Lucheng Fu et al. (+4 more)
Time-series foundation models provide strong zero-shot forecast, but deployment for real-world applications still requires task-specific designs for model inputs and outputs. Direct inference can leave domain knowledge and recurring forecast errors unaddressed, while tailored pipelines require substantial human expertise and effort. We introduce TimeRSI, a self-improving agentic deployment system around frozen forecasting models. A coding
agent translates task descriptions into executable pipeline changes. It tests each revision on historical forecasting windows and uses observed errors to guide subsequent revisions. During deployment, an adaptive selector chooses among the resulting pipelines using completed forecasts under similar conditions. Across 198 tasks on TIME and fev-bench, TimeRSI outperforms all submissions on six point and probabilistic forecasting metrics. Controlled comparisons support the value of feedback-guided revision over non-iterative pipeline search. Further experiments verify the generalization with different coding
agents and forecasting models. Code is available at https://github.com/haoxin1998/TimeRSI.
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All authors Haoxin Liu, Deqing Fu, Lucheng Fu, Yiqiao Jin, Rushi Qiang, Harshavardhan Kamarthi, B. Aditya Prakash
Discrete Mathematics
Graphs with Bounded Push-Pop Walk Orderings
Antoine Amarilli, Claire David, Nadime Francis et al. (+3 more)
Consider a directed graph G and the (generally infinite) set Walks(G) of the walks in that graph. We are interested in ordering Walks(G) as w1, w2,... in a way that ensures that each walk is obtained from the previous one by a bounded number of elementary operations, namely, push operations (which add a new edge at either end of the walk) and pop operations (which remove the first or last edge of the walk). Our goal is to optimize the aforementioned bound, when it exists, in particular when imposing the additional requirement that walks must be ordered in increasing order of length. To this end, we introduce a condition on graphs inspired by earlier work, called inner-connectedness, which is testable in linear time; we show that inner-connected graphs are precisely those which admit bounded walk orderings. Focusing on such graphs, we then introduce and study the pp-rank and the pp-increasing-rank. Namely, the pp-rank of a graph is the best possible bound on the number of push-pop operations in a bounded walk ordering for that graph; and the pp-increasing-rank is the same where we further impose that shorter walks appear before longer walks in the ordering. We show that the pp-rank of inner-connected graphs is in fact always bounded by 3. The pp-increasing-rank of inner-connected graphs is also always finite, but it can be up to linear in the input graph. More precisely, we show that the pp-increasing-rank is related to a new parameter we introduce, the peripherality of graphs. In particular, for cyclic graphs, peripherality is related to the pp-increasing-rank up to multiplicative and additive constants. We last study how to compute these parameters, and show that while peripherality can be computed in
polynomial time, the pp-increasing-rank itself is generally NP-hard to compute.
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All authors Antoine Amarilli, Claire David, Nadime Francis, Victor Marsault, Mikaël Monet, Yann Strozecki
Computation and Language
Recognizing Dialogue Ambiguity via Candidate Set Visual Grounding
Shun Inadumi, Lee Sangmyeong and Koichiro Yoshino
Interpreting an ambiguous utterance in real-world interactions often requires context beyond a single utterance. When the utterance refers to objects in a visual scene, it is necessary to maintain and update the set of plausible referents as context accumulates, without assuming that the available information identifies a unique object. However, prior work on interactive visual grounding, which localizes objects referred to by linguistic expressions, has focused on identifying a unique object once sufficient dialogue context becomes available. To address this gap, we propose Candidate Set Visual Grounding (CSVG), a task for estimating the set of objects consistent with the given dialogue context. We further introduce CandVG, a
benchmark that evaluates how the candidate set changes across dialogue turns. Our evaluation of
vision-
language models shows that stronger visual grounding capability does not necessarily yield better CSVG performance. In particular, models have difficulty predicting the complete candidate set, owing to challenges in candidate generation and premature commitment to a small set of candidates in early turns. Nevertheless, we find that this limitation can be partially mitigated in the evaluated large-scale models using instructions designed for CSVG.
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Sound
ONCship: A Large-Scale Underwater Acoustic Corpus for Ship Recognition
Zhe Cao, Jichao Zhang and Xiao-Lei Zhang
Recent advances in deep learning have significantly improved underwater acoustic vessel recognition. However, existing publicly available
datasets are typically limited in scale, hindering large-scale representation learning and downstream task evaluation. To address this limitation, we introduce ONCship, a large-scale underwater acoustic
dataset comprising 4521 hours of curated recordings from Ocean Networks Canada (ONC) hydrophones and Automatic Identification System (AIS) data. We evaluate the proposed
dataset across three tasks: self-supervised representation learning, vessel-type classification, and MMSI-Level Vessel Classification. Experiments on DeepShip and ShipsEar demonstrate the effectiveness of ONCship for acoustic representation learning, with joint pre-training on ONCship and AudioSet achieving a classification accuracy of 62.45% on DeepShip through linear probing. Furthermore, incorporating ONCship as auxiliary training data improves downstream vessel-type classification performance. Beyond conventional vessel-type classification, we further investigate MMSI-Level Vessel Classification, treating each vessel as a distinct identity. Experimental results show that models fine-tuned with different loss functions achieve Top-1 accuracies exceeding 53% and Top-5 accuracies approaching 69%, demonstrating the feasibility of distinguishing individual vessels through MMSI-Level Vessel Classification. Overall, ONCship provides a valuable resource for underwater acoustic representation learning and vessel recognition, while its rich vessel-level metadata enables further exploration of MMSI-Level Vessel Classification.
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Artificial Intelligence
Articulation Upper Bounds for Language Models
Alexander Spangher, Daniel E. Ho, Diyi Yang et al. (+2 more)
Language captures only a subset of the perceptions, intuitions and intents that form meaning between speakers. What, then, are the limits of
language? We take steps towards measuring this in LLMs as follows: for a set of concepts, we measure how well each concept can be transmitted between two LLMs as their capabilities scale. This requires novel measurement tools: (1) optimal messages: we introduce a
prompt optimization
algorithm that beats existing
algorithms by up to 14% on
benchmarks and accurately estimates
prompt upper bounds. (2) A transmission measure: the sender is asked to label text; the receiver then tries to recover the sender's
prompt, and recovery is measured; we find this correlates strongly with human label error. With these measures, we use observational scaling laws to study how transmissibility of a concept, conveyed with optimal messages, increases as transmitter and receiver capacity grows: does it asymptote below or above a threshold? Measuring 1.2k concepts in eight domains, we find concepts that (a) can be fully articulated; these concepts usually depend on local patterns, e.g. "joke ends with surprise"; (b) might be articulated by future, stronger models; these rely on whole-text structural patterns, e.g. "story's worldbuilding coherence"; (c) concepts that face articulability limits; these concepts' meaning, we find, is tied to identity and social-group awareness, e.g. "comic voice". Interesting, these same concepts are not all challenging for humans: humans have moderate-to-high levels of agreement in 76% of concepts that LLMs struggle with; articulation limits, we find, are executor relative. Finally, we characterize the nature of improvement in each case: while recoverable concepts can be articulated through definitions and explanations, irrecoverable concepts cannot be transmitted, even with examples, and might require novel learning mechanisms.
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All authors Alexander Spangher, Daniel E. Ho, Diyi Yang, Noah Goodman, Sanmi Koyejo
General Economics
Which Text Matters: Handling Model Uncertainty in Text-as-Data Regressions, with an Application to Central Bank Communication
Martin Feldkircher, Bernd Prostmaier, Paul Hofmarcher et al. (+1 more)
Social scientists routinely convert text into
covariates like topic shares, ideal points or sentiment scores, and insert them into statistical models of interest. This two-step design is convenient, but it is rarely guided by theory: little tells the analyst which text-based
covariates to construct or include. Each approach embodies contestable measurement choices, and competing operationalizations of the same construct can support different conclusions, so a single research question gives rise to a menu of competing regression models. Which text constructed
covariates belong in a model, and in what functional form, is thus a problem of model uncertainty. We propose spike-and-slab generalized additive models (SSGAMs), which jointly select
covariates and determine whether their effects are linear or nonlinear. We illustrate the approach with the communication of a powerful unelected institution, asking which of 45 competing text indicators from 224 monthly European Central Bank press conferences, spanning late 2002 to mid-2025, track professional inflation expectations. A sparse set is selected; widely used alternatives, and every tested nonlinear effect, carry no incremental information.
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All authors Martin Feldkircher, Bernd Prostmaier, Paul Hofmarcher, Pierre Siklos
Artificial Intelligence
Learning Individual Scientific Taste with Privileged Hindsight Distillation
Hanwei Fan, Yanqiao Wang, Yiqi Zhu et al. (+3 more)
Scientific taste shapes which research directions researchers pursue, and it varies across individuals. Existing work evaluates research directions along multiple evaluation criteria or models scientific taste using community feedback signals such as citations and reviews, but neither directly captures how individuals translate assessments under the same criteria into different preferences. We model scientific taste as a researcher-specific mapping from criterion-level assessments in a shared, evidence-grounded evaluation space with proposal-visible evidence, to relative preferences. A population-level mapping learned from retrospective supervision provides a cold start when individual feedback is scarce. We introduce Privileged Hindsight
Distillation (PHD), which uses later-emerging scientific evidence during training to improve proposal-time criterion assessment and the population mapping, while exposing only proposal-visible information at inference. We evaluate our approach primarily in
quantum research, where structured public reviews are largely unavailable, and use pairwise proposal comparison as a direct interface for observing individual taste. With only 15 comparisons per researcher, our method captures sharply different tastes, including opposing preferences over the same research-direction pairs when they trade off across evaluation criteria. In an interactive study, personalized rankings also surface proposals associated with greater subsequent user engagement, connecting learned taste to downstream research exploration.
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All authors Hanwei Fan, Yanqiao Wang, Yiqi Zhu, Xuanyu Lei, Peng Li, Yang Liu
Solar and Stellar Astrophysics
Evidence for Suppressed Non-thermal Broadening in a Flare Ribbon from Stereoscopic Observations
Ziwen Huang, L. P. Chitta and L. Teriaca
Flare ribbons mark the footpoints of newly reconnected
magnetic loops and are commonly associated with strong
plasma flows and enhanced non-thermal broadening of transition-region lines due to impulsive energy deposition. However, the mechanisms governing energy transport into
flare ribbons remain uncertain, particularly under different
magnetic field configurations. We investigate the energy deposition process at a
flare ribbon near a sunspot by determining the physical nature of its small-scale downflows. We study small-scale downflows in a remote ribbon during the M7.7-class event on 30 September 2024, using coordinated observations from SDO, IRIS, and Solar Orbiter. We use stereoscopic imaging from Solar Orbiter and IRIS to detect plane-of-sky motions on small scales (200 km). We conduct spectroscopic analysis of IRIS Si IV profiles, complemented by C II and Mg II diagnostics. Apparent downflow speeds measured from Solar Orbiter imaging (limb view) are 85-130 km/s, while IRIS images (disk view) reveal plane-of-sky speeds of 70-85 km/s. In contrast, IRIS Si IV profiles at the brightest ribbon pixels are well approximated by a single Gaussian, with minimal Doppler shifts and unexpectedly small non-thermal widths (10 km/s). Peak Si IV emission also coincides with a deeper Mg II central reversal, while electron densities are one to two orders of magnitude higher than typical quiet-Sun values. The absence of significant line-of-sight velocities and non-thermal broadening differs from typical
flare-ribbon behavior. Our results are consistent with a scenario in which
plasma motions are guided by highly inclined (nearly horizontal)
magnetic fields in chromospheric canopy and are not accompanied by strong
turbulence or wave motions. This study suggests that
flare ribbons can exhibit a wide diversity of lower-atmospheric responses and emphasizes the critical role of
magnetic field geometry.
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Computer Vision
No Way To Steal My Face: Proactive Defense Against Identity-Preserving Personalized Generation
Lizhi Xiong, Jun Li, Ziqiang Li et al. (+2 more)
Recent advances in
diffusion models have enabled high-fidelity, identity-preserving image generation for personalized applications such as digital avatars and virtual try-on systems. However, their reliance on sensitive facial reference images raises growing
privacy concerns. Existing defense mechanisms are primarily designed for training-based personalization and struggle to generalize to emerging training-free approaches, due to fundamental differences in their identity integration paradigms. To bridge this gap, we propose IDGuardian-the first generalizable and model-agnostic identity protection framework capable of defending against both training-based and training-free personalization methods. IDGuardian abstracts the personalization process into two critical stages: identity extraction and identity injection. It then introduces crafted
adversarial perturbations to simultaneously disrupt both stages. Specifically, it degrades the identity features extracted by external encoders and establishes an
adversarial conceptual bridge that misdirects the generative trajectory away from the target identity. Extensive experiments show that IDGuardian effectively protects identity across various personalization pipelines and model architectures, while remaining robust to post-processing, adaptive attacks, and cross-
dataset generalization. Our code is available at https://github.com/OpenAscent-L/IDGuardian.git.
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All authors Lizhi Xiong, Jun Li, Ziqiang Li, Weiwei Jiang, Zhangjie Fu
Sound
Soloist: A Generative Model for Blind Voice Separation in the Wild
Chen Yang, ChuFan Yu, Botian Jiang et al. (+5 more)
Real-world voice separation must recover individual voices from overlapping
speech, environmental noise, and music, yet isolated source recordings are rarely available for supervision. We introduce Soloist, a generative model for blind voice separation that autoregressively generates individual voice streams as audio-codec sequences conditioned on the mixture, without requiring a target-speaker query or a predefined voice count. We propose a two-stage training paradigm to learn from synthetic mixtures and adapt to real recordings. The first stage combines supervised separation on synthetic mixtures with isolated source targets and an auxiliary task that predicts speaker timelines from real recordings, learning who speaks when from natural acoustics. The second stage applies reinforcement learning to real recordings, with rewards supplied by a model judge that compares candidate separations based on voice purity and content preservation without isolated source targets. Across diverse scenarios, Soloist recovers clean
speech from multi-speaker overlap and noisy recordings, and extracts singing vocals from music accompaniment while maintaining relatively high pitch accuracy and intelligibility. On real-world recordings with unknown voice counts, Soloist also separates voices well. Finally, we integrate Soloist into a full-duplex conversation processing pipeline that assembles separated outputs into continuous speaker tracks, demonstrating its practical utility in real conversations.
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All authors Chen Yang, ChuFan Yu, Botian Jiang, Jingqi Chen, Wenxuan Wang, Yitian Gong, Zhaoye Fei, Xipeng Qiu
Information Theory
Capacity Bounds for Optical Interference Channels Subject to Average Power Constraints
Viswanathan Ramachandran
Accurate information-theoretic analysis of multiuser wavelength-division multiplexed (WDM) optical links is complicated by Kerr nonlinearity and chromatic dispersion. Existing capacity bounds for first-order regular perturbative (RP) channel models have relied on per-symbol peak power constraints to simplify the underlying extremal analysis. In this paper, we replace these peak constraints with the more practically relevant average input power constraints and study the resulting RP WDM interference channel. Unlike the peak-constrained formulation, an exact finite signal-to-noise ratio (SNR) analysis under average power leads in general to a nonconvex, high-dimensional optimization problem with no closed-form solution. We show that the problem admits a tractable characterization in the high-SNR regime. Using a genie-aided argument, we derive closed-form single-user high-SNR capacity bounds for the RP interference channel and identify constant-amplitude interferer signaling as extremal. Furthermore, under an empirically validated non-negativity condition on the dominant RP kernels and within a truncated first-order RP model, we establish a finite-SNR extremality result, yielding a single-user capacity characterization within the RP model under average power constraints. Building on these single-user corner points, we construct an all-helpsone achievable region via time sharing, which strictly improves upon treating nonlinear interference as noise. Numerical results and split-step
Fourier simulations of the nonlinear Schrodinger equation channel confirm that the qualitative conclusions persist over practical launch powers. The results provide new insight into extremal signaling and multiuser trade-offs for nonlinear WDM systems within the RP approximation.
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Robotics
Uncertainty-Driven Self-Play for Robust Multi-Agent Driving Policies
Sajad Marvi, Julian Schmidt, Alessandro Canevaro et al. (+2 more)
Learning robust driving policies that generalize beyond their training domain remains a central challenge in motion planning. We propose an uncertainty-driven self-play scheme, in which half of the
agents are rewarded for increasing their neighbors' epistemic uncertainty, while the other half learn to drive safely as the exploring
agents continuously seek out their weaknesses. Epistemic uncertainty indicates where the policy is least confident and serves as an automatic proxy for scenario difficulty. Exploring
agents use this signal to seek out hard cases, generating a challenging curriculum without manual scenario design. The resulting policy outperforms standard self-play, achieving best-in-class zero-shot transfer to nuplan Val14 (99.12% vs. 97.97%) and Argoverse 2 (82.39% vs. 78.03%) without fine-tuning, while also improving performance over standard self-play on Waymo. Our diversity-driven approach achieves 85% higher LSTM hidden-state coverage than the baseline, indicating a much richer set of behaviors. Further analysis shows that epistemic uncertainty serves as a calibrated difficulty detector, with highest-uncertain
agents exhibiting 14.8 times the combined failure rate across collision, off-road, and DNF, of lowest-uncertain
agents, enabling automatic prioritization of challenging scenarios without ground-truth labels.
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All authors Sajad Marvi, Julian Schmidt, Alessandro Canevaro, Julian Jordan, Abhinav Valada
Strongly Correlated Electrons
Room-Temperature Metallic 2D Ferromagnetism Stabilized by Quantum Metric
Teng-Fei Ying, Jianqi Zhong, Songyuan Geng et al. (+3 more)
The recent discovery of long-sought dice-
lattice bands in layered electride YCl opens up unprecedented opportunities for studying correlated electrons in real dice
lattice systems. While the weakly dispersive band at the Fermi level is partially filled and density-wave states are expected due to Fermi surface nesting based on conventional theories, the ARPES measurement nevertheless revealed a uniform flat band splitting of 0.5 eV, suggesting unusual ferromagnetism (FM) borne out of the metallic 2D dice
lattice. In this Letter, we propose that the uniform metallic FM order is stabilized by the prominent
quantum metric near topological band crossing points at K and K', which reconstructs the
magnetic instability in the dice metal and tips the density-wave instability toward a uniform FM order. Importantly, our analysis based on random phase approximation (RPA) and Hartree-Fock theory predicts a remarkably high Curie temperature above room temperature for the 2D FM order. These findings establish the first example of a room-temperature 2D metallic magnet stabilized by
quantum metric, which not only exemplifies the fundamental significance of
quantum geometry in solids but also bears far-reaching applications in energy-efficient high-density
magnetic memories.
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All authors Teng-Fei Ying, Jianqi Zhong, Songyuan Geng, Fangjie Chen, Haoxiang Li, Benjamin T. Zhou
Machine Learning
New Model, Old Habits: Behavior Transfer under Model Swapping in Multi-Session LLM Agents
Youngbin Choi, Sehyun Hwang, Suhyeon Jun et al. (+4 more)
Multi-session
agents can switch between LLMs to balance performance and inference cost. Such switches require transferring a history for continuity, yet their effects on the recipient remain underexplored. Through controlled experiments with multi-session tasks, we uncover behavior transfer: recipients tend to adopt
reasoning and action patterns from the models that generated their histories. This effect is most evident with raw-history transfer but is substantially reduced by summarization. Based on these findings, we propose Direction- and Authorship-aware Summarization of History (DASH) that preserves stronger-model behavior while minimizing weak-to-strong transfer via summarization. Experiments with repeated swaps show that DASH outperforms raw-history transfer and naive summarization baselines. These results suggest that effective multi-model orchestration requires considering not only which model to use, but also which behavioral patterns to carry forward.
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All authors Youngbin Choi, Sehyun Hwang, Suhyeon Jun, Seoyeon Lee, Sunghyun Choi, MoonJeong Park, Dongwoo Kim