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2512.10240 2026-04-09 cs.SI cs.DL

The Circulate and Recapture Dynamic of Fan Mobility in Agency-Affiliated VTuber Networks

Tomohiro Murakami, Mitsuo Yoshida

Comments IEEE BigData 2025 Workshop : The 10th International Workshop on Application of Big Data for Computational Social Science (ABCSS 2025)

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英文摘要

VTuber agencies -- multichannel networks (MCNs) that bundle Virtual YouTubers (VTubers) on YouTube -- curate portfolios of channels and coordinate programming, cross appearances, and branding in the live-streaming VTuber ecosystem. It remains unclear whether affiliation binds fans to a single channel or instead encourages movement within a portfolio that buffers exit, and how these micro level dynamics relate to meso level audience overlap. This study examines how affiliation shapes short horizon viewer trajectories and the organization of audience overlap networks by contrasting agency affiliated and independent VTubers. Using a large, multiyear, fan centered panel of VTuber live stream engagement on YouTube, we construct monthly audience overlap between creators with a similarity measure that is robust to audience size asymmetries. At the micro level, we track retention, changes in the primary creator watched (oshi), and inactivity; at the meso level, we compare structural properties of affiliation specific subgraphs and visualize viewer state transitions. The analysis identifies a pattern of loose mobility: fans tend to remain active while reallocating attention within the same affiliation type, with limited leakage across affiliation type. Network results indicate convergence in global overlap while local neighborhoods within affiliated subgraphs remain persistently denser. Flow diagrams reveal circulate and recapture dynamics that stabilize participation without relying on single channel lock in. We contribute a reusable measurement framework for VTuber live streaming that links micro level trajectories to meso level organization and informs research on creator labor, influencer marketing, and platform governance on video platforms. We do not claim causal effects; the observed regularities are consistent with proximity engineered by VTuber agencies and coordinated recapture.

2512.10233 2026-04-09 cs.SI cs.DL

Understanding Toxic Interaction Across User and Video Clusters in Social Video Platforms

Qiao Wang, Liang Liu, Mitsuo Yoshida

Comments IEEE BigData 2025 Workshop : The 10th International Workshop on Application of Big Data for Computational Social Science (ABCSS 2025)

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英文摘要

Social video platforms shape how people access information, while recommendation systems can narrow exposure and increase the risk of toxic interaction. Previous research has often examined text or users in isolation, overlooking the structural context in which such toxic interactions occur. Without considering who interacts with whom and around what content, it is difficult to explain why negative expressions cluster within particular communities. To address this issue, this study focuses on the Chinese social video platform Bilibili, incorporating video-level information as the environment for user expression, modeling users and videos in an interaction matrix. After normalization and dimensionality reduction, we perform separate clustering on both sides of the video-user interaction matrix with K-means. Cluster assignments facilitate comparisons of user behavior, including message length, posting frequency, and source (barrage and comment), as well as textual features such as sentiment and toxicity, and video attributes defined by uploaders. Such a clustering approach integrates structural ties with content signals to identify stable groups of videos and users. We find clear stratification in interaction style (message length, comment ratio) across user clusters, while sentiment and toxicity differences are weak or inconsistent across video clusters. Across video clusters, viewing volume exhibits a clear hierarchy, with higher exposure groups concentrating more toxic expressions. For such a group, platforms should require timely intervention during periods of rapid growth. Across user clusters, comment ratio and message length form distinct hierarchies, and several clusters with longer and comment-oriented messages exhibit lower toxicity. For such groups, platforms should strengthen mechanisms that sustain rational dialogue and encourage engagement across topics.

2512.09600 2026-04-09 physics.ins-det cond-mat.supr-con

Advanced microwave SQUID multiplexer model incorporating readout power effects and Josephson junction inhomogeneities

Martin Neidig, Mathias Wegner, Sebastian Kempf

Comments This article has been submitted to Superconductor Science and Technology

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英文摘要

We present an advanced model for describing the readout power dependence of the resonance characteristics of a microwave SQUID multiplexer. Our model proves valid for SQUID screening parameters up to $β_\mathrm{L}<1$, hence covering the full range of practically relevant design parameters. We demonstrate that our model significantly improves agreement with experimental data compared to the existing models, thereby enabling optimization beyond the previously accessible parameter space. Moreover, our model supports non-sinusoidal current-phase relations of the rf-SQUID's Josephson junction, allowing, for the first time, for the modeling of devices based on Josephson tunnel junctions with inhomogeneous tunnel barriers. We show that the effects of such inhomogeneities are qualitatively similar to, yet distinct from, those of the screening parameter, making their inclusion essential for accurate characterization. Incorporating these effects yields great improved agreement with measurements, even at readout power conditions well beyond typical operating parameters.

2512.09379 2026-04-09 hep-ex

Probing $t$-channel single top-quark and antiquark production via differential cross-section measurements at $\sqrt{s}=$\SI{13}{\TeV} with the ATLAS detector

Lukas Kretschmann

Comments Poster at the 18th International Workshop on Top Quark Physics (Top2025), 21-26 September 2025

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英文摘要

The differential production cross-sections of single top quarks and top antiquarks produced via the $t$-channel process are measured in proton-proton collisions at $\sqrt{s}=13$TeV at the LHC with the full Run~2 ATLAS dataset corresponding to an integrated luminosity of \SI{140}{\femto\barn^{-1}}. The cross-sections are measured as a function of the transverse momentum and absolute rapidity of the top quark ($tq$) and top antiquark ($\bar{t}q$) at parton level. In addition, for the first time, the differential ratio of the $tq$ to $\bar{t}q$ cross-sections is presented. The results are compared to theoretical predictions from fixed-order calculations, various event generators, and different PDF sets. An interpretation in the framework of an effective field theory (EFT) is performed to constrain the Wilson coefficient $C^{3,1}_{Qq}$ of the four-fermion operator.

2512.07718 2026-04-09 cond-mat.mtrl-sci cs.SY eess.SY

Bimorph Lithium Niobate Piezoelectric Micromachined Ultrasonic Transducers

Vakhtang Chulukhadze, Zihuan Liu, Ziqian Yao, Lezli Matto, Tzu-Hsuan Hsu, Nishanth Ravi, Xiaoyu Niu, Michael E. Liao, Mark S. Goorsky, Neal Hall, Ruochen Lu

Comments 13 pages, 22 figures

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Journal ref
IEEE Transactions on Ultrasonics ( Early Access ) 2026
英文摘要

Piezoelectric micromachined ultrasonic transducers (PMUTs) are widely utilized in applications that demand mechanical resilience, thermal stability, and compact form factors. Recent efforts have sought to demonstrate that single-crystal lithium niobate (LN) is a promising PMUT material platform, offering high electromechanical coupling (k2) and bidirectional performance. In addition, advances in LN film transfer technology have enabled high quality periodically poled piezoelectric films (P3F), facilitating a bimorph piezoelectric stack without intermediate electrodes. In this work, we showcase a bimorph PMUT incorporating a mechanically robust, 20 $μ$m thick P3F LN active layer. We establish the motivation for LN PMUTs through a material comparison, followed by extensive membrane geometry optimization and subsequent enhancement of the PMUT's k2. We demonstrate a 775 kHz flexural mode device with a quality factor (Q) of 200 and an extracted k2 of 6.4\%, yielding a high transmit efficiency of 65 nm/V with a mechanically robust active layer. We leverage the high performance to demonstrate extreme-temperature resilience, showcasing stable device operation up to 600 $^\circ$C and survival up to 900 $^\circ$C, highlighting LN's potential as a resilient PMUT platform.

2512.06779 2026-04-09 cs.CE

A Texture-Generalizable Deep Material Network via Orientation-Aware Interaction Learning for Polycrystal Modeling and Texture Evolution

Ting-Ju Wei, Tung-Huan Su, Chuin-Shan Chen

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英文摘要

Machine learning surrogate models have emerged as a promising approach for accelerating multiscale materials simulations while preserving predictive fidelity. Among them, the Orientation-aware Interaction-based Deep Material Network (ODMN) provides a hierarchical homogenization framework in which material nodes encode crystallographic texture and interaction nodes enforce stress equilibrium under the Hill--Mandel condition. Trained solely on linear-elastic stiffness data, ODMN captures intrinsic microstructure--mechanics relationships, enabling accurate prediction of nonlinear mechanical responses and texture evolution. However, its applicability remains fundamentally limited by the absence of a parametric mapping from arbitrary microstructures to the ODMN parameter space. This limitation necessitates retraining for each new microstructure. To address this challenge, we reformulate ODMN generalization as a microstructure-to-parameter inference problem and propose the TACS--GNN--ODMN framework. The proposed framework combines a Texture-Adaptive Clustering and Sampling (TACS) scheme for texture representation with a Graph Neural Network (GNN) for inferring micromechanical equilibrium parameters. This strategy enables the construction of fully parameterized ODMNs for previously unseen microstructures without retraining. Numerical results demonstrate that the proposed framework accurately predicts nonlinear mechanical responses and texture evolution across diverse texture distributions. The predicted responses show close agreement with direct numerical simulations (DNS), highlighting the framework as a generalizable and physically interpretable surrogate model for microstructure-informed multiscale materials simulations.

2512.05876 2026-04-09 eess.SY cs.SY

Context-Aware Model Predictive Control for Microgrid Energy Management via LLMs

Ruixiang Wu, Jiahao Ai, Tinko Sebastian Bartels, Tongxin Li

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英文摘要

The optimal operation of modern microgrids, particularly those integrating stochastic renewable generation and battery energy storage system (BESS), relies heavily on load and disturbances forecasting to minimize operational costs. However, in environments with uncertainties in both generation and consumption, traditional numerical forecasting methods often fail to capture generation shifts and event-driven load surges. While contextual information regarding event schedules, system logs, and computational task records is easily obtainable, classic control paradigms lack a formal interface to integrate the unstructured, semantic data into the physical operation loop. This paper addresses this gap by introducing the InstructMPC framework, which utilizes a Large Language Model (LLM) paired with a tunable last layer mapping to translate unstructured operational context into predictive disturbance trajectories for the MPC controller. Unlike conventional forecasting methods, the proposed approach treats the last layer mapping as a tunable component, refined online based on the realized control cost. We establish a theoretical foundation for this closed-loop tuning strategy, proving a regret bound of $O(\sqrt{T \log T})$ for linear systems under a tailored task-aware loss function, together with robustness guarantees against uninformative or noisy textual inputs. The control strategy is experimentally validated on OpenCEM, a real-world microgrid with highly fluctuating generation and consumption. Experimental results demonstrate that the LLM-driven MPC significantly reduces cumulative grid electricity costs compared to classical context-agnostic baselines, validating the efficacy of integrating semantic information directly into physical control loops.

2512.04379 2026-04-09 math.CV

Properties for ($α,β$)-harmonic functions

Jinjing Qiao, Jiale Chang, Antti Rasila

Comments 32 pages

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英文摘要

We investigate properties of ($α,β$)-harmonic functions. First, we discuss the coefficient estimates for ($α,β$)-harmonic functions. In particular, we obtain Heinz's inequality for ($α,β$)-harmonic functions, propose a coefficient bound for normalized univalent ($α,β$)-harmonic functions and prove that this holds for the subclass that consists of starlike functions. Furthermore, by utilizing the relationship between ($α,β$)-harmonic functions and harmonic functions, we obtain Radó's theorem, Koebe type covering theorems and an area theorem. Finally, we show growth estimates and distortion estimates for ($α,β$)-harmonic functions by using the $L^p$ norms of the boundary functions.

2512.02632 2026-04-09 physics.optics

GaN mid-IR plasmonics: low-loss epsilon-near-zero modes

Julia Inglés-Cerrillo, Maria Villanueva-Blanco, Benjamin Damilano, Stéphane Vézian, Miguel Montes Bajo, Adrian Hierro

Comments 18 pages, 5 figures

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Journal ref
Adv. Optical Mater. 2026, e03829
英文摘要

Epsilon-near-zero (ENZ) materials, defined by $ | Re(ε) | < 1$, enable unique light propagation characteristics, including confinement within sub-wavelength regions. To reduce losses in this regime, materials with both near-zero permittivity and $n<1$ refractive index, known as near-zero-index (NZI) materials, are desired. When both conditions are satisfied, the resulting region is classified as a low-loss ENZ medium combining strong light confinement with reduced optical losses. To achieve this behavior in the mid-IR, heavily doped semiconductors are required, and those compatible with current technologies are most desirable. This work provides the first in-depth study, supported by experimental demonstrations, of the plasmonic properties of highly doped GaN thin films on Si, exhibiting low optical losses and low-loss ENZ characteristics up to $3μm$. From the extracted optical parameters, the ENZ and NZI regions are determined and compared with the existing literature. As a result of the large polar character of nitrides, a hybridization of the surface plasmon and phonon polaritons is observed, accompanied by a flat-dispersion of the high-energy mode (pinned near the plasma frequency) indicative of its ENZ character. Establishing GaN as a viable platform for mid-IR ENZ-based plasmonics paves the way for integration into future infrared photonic technologies.

2512.02503 2026-04-09 q-bio.NC

Individual-specific precision neuroimaging of learning-related plasticity

Simon Leipold, Ryssa Moffat

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英文摘要

Studying learning-related plasticity is central to understanding the acquisition of complex skills, for example learning to master a musical instrument. Over the past three decades, conventional group-based functional magnetic resonance imaging (fMRI) studies have advanced our understanding of how humans' neural representations change during skill acquisition. However, group-based fMRI studies average across heterogeneous learners and often rely on coarse pre- versus post-training comparisons, limiting the spatial and temporal precision with which neural changes can be estimated. Here, we outline an individual-specific precision approach that tracks neural changes within individuals by collecting high-quality neuroimaging data frequently over the course of training, mapping brain function in each person's own anatomical space, and gathering detailed behavioral measures of learning, allowing neural trajectories to be directly linked to individual learning progress. Complementing fMRI with mobile neuroimaging methods, such as functional near-infrared spectroscopy (fNIRS), will enable researchers to track plasticity during naturalistic practice and across extended time scales. This multi-modal approach will enhance sensitivity to individual learning trajectories and will offer more nuanced insights into how neural representations change with training. We also discuss how findings can be generalized beyond individuals, including through statistical methods based on replication in additional individuals. Together, this approach allows researchers to design highly informative longitudinal training studies that advance a personalized account of skill learning in the human brain.

2512.02305 2026-04-09 math.DG

Remarks on Kähler orbifolds of non-negative Ricci curvature

Yuguang Zhang

Comments Appendix A contains a corollary obtained by an AI

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英文摘要

This note proves orbifold versions of Kobayashi's theorem. The main result asserts that a compact Kähler orbifold with non-negative Ricci curvature, along with certain conditions regarding singularities, is simply connected.

2512.02156 2026-04-09 quant-ph gr-qc hep-th

Testing ER = EPR with Hydrogen

Irfan Javed, Edward Wilson-Ewing

Comments 7 pages. v2: Clarifications added. Published with the title "Testing wormhole-mediated entanglement with hydrogen"

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Journal ref
Phys. Rev. Lett. 136, 121501 (2026)
英文摘要

According to the ER = EPR conjecture, entangled particles are connected by quantum wormholes. Under the assumption that some of the electric field surrounding an entangled charged particle leaks into the wormhole, we show that this effect will modify the hyperfine structure of the hydrogen atom. In addition, if the quantum wormholes are non-traversable, this will also lead to a non-zero total effective charge for the hydrogen atom. These effects provide strong constraints on the amplitude of this potential ER = EPR effect, given high-precision measurements of the hydrogen atom's hyperfine structure and total charge.

2512.01982 2026-04-09 quant-ph physics.hist-ph

A Heptalemma for Quantum Mechanics

John B. DeBrota, Christian List

Comments 36 pages, 1 figure, 1 table. v2: Minor updates after feedback

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Journal ref
Foundations of Physics 56, 24 (2026)
英文摘要

We present a seven-pronged no-go result for quantum mechanics: a "heptalemma". It shows that seven initially plausible theses about physical reality are jointly inconsistent with the predictions of quantum mechanics, while any six are jointly consistent. We must then decide which theses to retain and which to give up. Since different interpretations of quantum mechanics entail different responses to the heptalemma, we get a novel taxonomy of such interpretations. Beyond the application to quantum mechanics, the heptalemma offers a general diagnostic criterion for determining whether a given scientific domain should count as classical or not, and if not, how it departs from classicality.

2512.01423 2026-04-09 stat.ME

Active Hypothesis Testing under Computational Budgets with Applications to GWAS and LLM

Qi Kuang, Bowen Gang, Yin Xia

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英文摘要

In large-scale hypothesis testing, computing exact $p$-values or $e$-values is often resource-intensive, creating a need for budget-aware inferential methods. We propose a general framework for active hypothesis testing that leverages inexpensive auxiliary statistics to allocate a global computational budget. For each hypothesis, our data-adaptive procedure probabilistically decides whether to compute the exact test statistic or a transformed proxy, guaranteeing a valid $p$-value or $e$-value while satisfying the exact budget constraint. Theoretical guarantees are established for our constructions, showing that the procedure achieves optimality for $e$-values and for $p$-values under independence, and admissibility for $p$-values under general dependence. Empirical results from simulations and two real-world applications, including a large-scale genome-wide association study (GWAS) and a clinical prediction task leveraging large language models (LLM), demonstrate that our framework improves statistical efficiency under fixed resource limits.

2512.00448 2026-04-09 q-fin.CP

Efficient Simulation and Calibration of the Rough Bergomi Model via Wasserstein Distance

Changqing Teng, Guanglian Li

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Despite the empirical success of the rough Bergomi (rBergomi) model in modeling volatility dynamics, its practical use remains challenging due to high computational complexity in both pricing and calibration arising from its non-Markovian structure. To address these difficulties, we develop an efficient computational framework. First, we propose a modified-sum-of-exponentials (mSOE) Monte Carlo scheme within the class of hybrid multifactor approximations. The method combines an exact treatment of the singular kernel over the first time step with a sum-of-exponentials approximation over the remaining time interval, and exact Gaussian simulation of the resulting multifactor components. For a fixed number of exponential terms, the method maintains linear online complexity with respect to the number of time steps. It achieves high pricing accuracy in numerical experiments, particularly for out-of-the-money options. Second, building on this pricing engine, we formulate a calibration approach based on distributional matching of the terminal underlying asset via the Wasserstein-1 distance. Instead of fitting option prices only at selected strikes, this method compares model-generated and market-implied terminal distributions through the Kantorovich-Rubinstein dual representation. Numerical experiments indicate that the mSOE scheme exhibits stable convergence, and the Wasserstein-based calibration scheme improves parameter recovery, optimization stability, and out-of-sample performance relative to conventional MSE-based fitting in the rBergomi setting considered in this paper.

2511.20326 2026-04-09 cond-mat.quant-gas

Bloch oscillations of a mobile impurity in a one-dimensional Bose gas

Saptarshi Majumdar, Aleksandra Petković

Comments 12 pages, 12 figures

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Journal ref
Phys. Rev. A 113, 043309, 2026
英文摘要

We study the motion of an impurity under the action of a constant force through a one-dimensional system of weakly-interacting bosons. The interplay of the impurity-boson interaction, the boson-boson interaction, and the driving force gives rise to a rich dynamics. We focus on the influence of a finite external force. Under these far-from-equilibrium conditions, we show that in a wide range of forces, one part of the momentum transferred to the system is periodically channeled into the Bose gas through the emission of dispersive density shock waves, solitons, density waves and the creation of additional phase gradients. As a result, the impurity velocity does not increase indefinitely, but periodically oscillates in time around the drift velocity. We uncover and characterize different dynamical regimes in a wide range of the impurity-boson coupling, the impurity mass and the external force. At a sufficiently large force, the Bloch oscillations cease and the impurity exhibits an unlimited acceleration.

2511.20239 2026-04-09 eess.SY cs.SY

Occlusion-Aware Multi-Object Tracking via Expected Probability of Detection

Jan Krejčí, Oliver Kost, Yuxuan Xia, Lennart Svensson, Ondřej Straka

Comments Accepted for publication in IEEE Transactions on Aerospace and Electronic Systems (TAES)

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英文摘要

This paper addresses multi-object systems, where objects may occlude one another relative to the sensor. The standard point-object model for detection-based sensors is enhanced so that the probability of detection considers the presence of all objects. A principled tracking method is derived, assigning each object an expected probability of detection, where the expectation is taken over the reduced Palm density, which means conditionally on the object's existence. The assigned probability thus considers the object's visibility relative to the sensor, under the presence of other objects. Unlike existing methods, the proposed method systematically accounts for uncertainties related to all objects in a clear and manageable way. The method is demonstrated through a visual tracking application using the multi-Bernoulli mixture (MBM) filter with marks.

2511.20164 2026-04-09 math.AG

Stability conditions on a singular quadric threefold

Tzu-Yang Chou

Comments 15 pages

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英文摘要

Let $X \subset \mathbb{P}^4$ be a quadric threefold with a single ordinary double point, and let $\mathcal{K}u(X)$ be its Kuznetsov component. In this paper, we construct a weak stability condition on Kuznetsov's categorical resolution $\widetilde{D} \subset \mathrm{D^b}(\widetilde{X})$, compatible with the Verdier localization $\mathbf{R}π_* \colon \widetilde{D} \to \mathrm{D^b}(X)$, and hence obtain a Bridgeland stability condition on $\mathrm{D^b}(X)$. Restricting the construction, we obtain the corresponding statement for $\mathcal{K}u(X)$ and its categorical resolution $\widetilde{D}'$. These can be viewed as a three-dimensional analogue of our previous result in \cite{Cho25}. We describe the geometry of the blow-up $π\colon \widetilde{X} \to X$ and obtain two semiorthogonal decompositions of $\mathrm{D^b}(\widetilde{X})$, arising from the projective bundle structure of $\widetilde{X}$ and from Kuznetsov's categorical resolution. Comparing them, we isolate an admissible subcategory $\widetilde{\mathcal{D}}\subset \mathrm{D^b}(\widetilde{X})$ resolving $\mathrm{D^b}(X)$ and show that it admits a full Ext-exceptional collection, from which we construct the localization-compatible weak stability condition.

2511.19568 2026-04-09 cs.IT eess.SP math.IT math.PR

Rao-Blackwellized Coverage Estimation in Poisson Networks: A High-Fidelity Hybrid Framework

Sunder Ram Krishnan, Junaid Farooq, Kumar Vijay Mishra, Xingchen Liu, S. Unnikrishna Pillai, Theodore S. Rappaport

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英文摘要

While stochastic geometry provides a powerful framework for the analysis of cellular networks, standard Monte Carlo simulations often suffer from slow convergence due to the stochasticity of the infinite far-field. This work introduces the \textit{Rao-Blackwellized Hybrid Estimator} (RBHE), which enhances simulation efficiency by analytically marginalizing the residual far-field interference via the conditional Laplace functional. By partitioning the interference field into $K$ dominant interferers and an infinite tail, we derive an estimator that combines exact spatial sampling with a rigorous analytical representation. We prove that the RBHE is an unbiased estimator for any finite truncation, while its systematic bias relative to the infinite-plane benchmark decays at a rate of $\mathcal{O}(K^{1-η/2})$. Numerical results demonstrate significant sample parsimony; in the high-reliability regime ($T = -10$ dB) with $K=2$, the RBHE yields a variance reduction gain of $90.75\times$, enabling a $98.90\%$ reduction in the spatial realizations required to reach a target precision. This framework effectively bridges the gap between tractable analytical models and high-fidelity simulations.

2511.14080 2026-04-09 gr-qc hep-th

Periodic orbits and their gravitational wave radiations in $γ$-metric

Chao Zhang, Tao Zhu

Comments 19 pages, 14 figures

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Journal ref
Eur. Phys. J. C 86, 350 (2026)
英文摘要

The $γ$-metric, also known as Zipoy-Voorhees spacetime, is a static, axially symmetric vacuum solution to Einstein's field equations characterized by two parameters: mass and the deformation parameter $γ$. It reduces to the Schwarzschild metric when $γ= 1$. In this paper, we explore potential signatures of the $γ$-metric on periodic orbits and their gravitational-wave radiation. Periodic orbits are classified by a rotational number specified by three topological numbers $(z, w, v)$, each triple corresponding to characteristic zoom-whirl behavior. We show that deviations from $γ=1$ alter the radii and angular momentum of bound orbits and thereby shift the $(z, w, v)$ taxonomy. We also compute representative gravitational waveforms for certain periodic orbits and demonstrate that $γ\neq 1$ can induce phase shifts and amplitude modulations correlated with changes in the zoom-whirl structure. In particular, larger zoom numbers lead to increasingly complex substructures in the waveforms, and finite deviations from $γ=1$ can significantly modify these features. Our results indicate that precise measurements of waveform morphology from extreme-mass-ratio inspirals may constrain deviations from spherical symmetry encoded in $γ$.

2511.11897 2026-04-09 eess.SY cs.SY

Sampling-Aware Control Barrier Functions for Safety-Critical and Finite-Time Constrained Control

Shuo Liu, Wei Xiao, Calin A. Belta

Comments 8 pages, 4 figures

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英文摘要

In safety-critical control systems, ensuring both safety and feasibility under sampled-data implementations is crucial for practical deployment. Existing Control Barrier Function (CBF) frameworks, such as High-Order CBFs (HOCBFs), effectively guarantee safety in continuous time but may become unsafe when executed under zero-order-hold (ZOH) controllers due to inter-sampling effects. Moreover, they do not explicitly handle finite-time reach-and-remain requirements or multiple simultaneous constraints, which often lead to conflicts between safety and reach-and-remain objectives, resulting in feasibility issues during control synthesis. This paper introduces Sampling-Aware Control Barrier Functions (SACBFs), a unified framework that accounts for sampling effects and high relative-degree constraints by estimating and incorporating Taylor-based upper bounds on barrier evolution between sampling instants. The proposed method guarantees continuous-time forward invariance of safety and finite-time reach-and-remain sets under ZOH control. To further improve feasibility, a relaxed variant (r-SACBF) introduces slack variables for handling multiple constraints realized through time-varying CBFs. Simulation studies on a unicycle robot demonstrate that SACBFs achieve safe and feasible performance in scenarios where traditional HOCBF methods fail.

2511.11120 2026-04-09 quant-ph hep-th math-ph math.MP

Magnetic flux and its topological effects in Aharonov-Bohm effect

Manvendra Somvanshi, D. Jaffino Stargen

Comments 7 pages, 1 figure

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英文摘要

The Aharonov-Bohm effect is a physical phenomenon in which the quantum state of a charged particle acquires a phase shift that is directly proportional to the magnetic flux, $Φ$, due to a (classical) magnetic field, ${\mathbf B}$, which is confined in a spatial region from which the magnetic field cannot escape. Even though the charged particle is not allowed to interact with the magnetic field, it accumulates a phase shift that affects the interference pattern produced. Not surprisingly, this apparent nonlocality is puzzling and counter intuitive. In this work, we provide an explanation that explains the physics underlying this apparent nonlocality. We find that the role of the confined magnetic field is to impart a puncture in the configuration space, $\mathbb{R}^2$, of the charge. Therefore, the quantum state corresponding to the charged quantum particle acquires the phase shift due to its response to the modified topology of the configuration space, $\mathbb{R}^2-\{0\}$, corresponding to the charge.

2511.10782 2026-04-09 astro-ph.EP astro-ph.IM

Historical Surveys to Rubin First Look: Absolute Colors of trans-Neptunian objects

Milagros Colazo, Alvaro Alvarez-Candal

Comments Submitted to The Planetary Science Journal (PSJ) on November 13, 2025

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英文摘要

We present a comprehensive photometric study of trans-Neptunian objects (TNOs) by combining data from SDSS, Col-OSSOS, DES, and the recent Rubin First Look (RFL) data. Our database comprises 43 677 measurements in the u, g, r, i, and z filters, from which we derived 2 193 phase curves for 781 unique objects. From these data, we computed 2 542 absolute color measurements for 633 objects, allowing a statistical characterization of phase coloring effects. Our results show correlations between colors at opposition and their variation with phase angle, indicating that redder (bluer) objects tend to become redder (bluer) as the phase angle increases. With a larger sample and the application of phase corrections, the colors show no strong bimodality nor correlation with orbital parameters. Notably, our dataset includes the first photometric measurements from Rubin Observatory during RFL, covering eight objects: five newly discovered TNOs and three previously known. These early LSST observations occupy sparsely sampled regions of parameter space, particularly at faint magnitudes, highlighting the discovery and characterization potential of the full survey.

2511.10249 2026-04-09 cs.NI

P4-TAS: P4-Based Time-Aware Shaper for Time-Sensitive Networking

Fabian Ihle, Moritz Flüchter, Michael Menth

Comments Uploaded peer-reviewed, accepted version

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英文摘要

Time-sensitive networking (TSN) is a set of IEEE standards that extends Ethernet with real-time capabilities. Among its mechanisms, the time-aware shaper (TAS) periodically opens and closes egress queues to protect scheduled traffic from lower-priority flows, ensuring low latency and bounded delay. Deterministic networking (DetNet), standardized by the IETF, provides similar guarantees at Layer 3 and can leverage TSN mechanisms such as the TAS. Commercially available TSN-capable switches implement TAS in hardware but rarely disclose internal delays in the TAS mechanism itself. Such delays directly affect scheduling precision, yet information about them is largely unavailable to system designers. In this work, we present P4-TAS, a P4-based implementation of the TAS on the Intel Tofino 2 switching ASIC that additionally supports per-stream filtering and policing (PSFP) and PTP time synchronization. First, we design a novel mechanism for periodic queue control that uses a continuous stream of internally generated control frames for time-triggered queue state updates. To the best of our knowledge, this enables TAS on a P4-programmable ASIC for the first time. P4-TAS additionally provides an MPLS/TSN translation layer that enables TSN time-based shaping to be applied at the boundary between TSN and DetNet domains, supporting line rates up to 400 Gb/s per port. Second, we identify and quantify three sources of internal delay that affect the precision of TAS gate transitions, providing transparency that enables more accurate TAS configuration. Our evaluation demonstrates a worst-case accumulated internal delay of 86 ns between time slices, which is well below values reported for commercial switches. Third, we propose a measurement methodology to externally measure TAS time slice accuracy, and introduce gate switching intervals (GSIs) to mitigate overlap between consecutive time slices.

2511.08734 2026-04-09 eess.SY cs.SY

Hierarchical Strategic Decision-Making in Layered Mobility Systems

Mingjia He, Zhiyu He, Jan Ghadamian, Florian Dörfler, Emilio Frazzoli, Gioele Zardini

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英文摘要

Mobility systems are complex socio-technical environments influenced by multiple stakeholders with hierarchically interdependent decisions, rendering effective control and policy design inherently challenging. We bridge hierarchical game-theoretic modeling with online feedback optimization by casting urban mobility as a tri-level Stackelberg game (travelers, operators, municipality) closed in a feedback loop. The municipality iteratively updates taxes, subsidies, and operational constraints using a projected two-point (gradient-free) scheme, while lower levels respond through equilibrium computations (Frank-Wolfe for traveler equilibrium; operator best responses). This model-free pipeline enforces constraints, accommodates heterogeneous users and modes, and scales to higher-dimensional policy vectors without differentiating through equilibrium maps. On a real multimodal network for Zurich, Switzerland, our method attains substantially better municipal objectives than Bayesian optimization and Genetic algorithms, and identifies integration incentives that increase multimodal usage while improving both operator objectives. The results show that feedback-based regulation can steer competition toward cooperative outcomes and deliver tangible welfare gains in complex, data-rich mobility ecosystems.

2511.07859 2026-04-09 cs.DS

Deterministic Padded Decompositions and Negative-Weight Shortest Paths

Jason Li

Comments STOC 2026, 12 pages

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英文摘要

We obtain the first near-linear time deterministic algorithm for negative-weight single-source shortest paths on integer-weighted graphs. Our main ingredient is a deterministic construction of a padded decomposition on directed graphs, which may be of independent interest.

2511.06091 2026-04-09 cs.SI

Characterizing AI Manipulation Risks in Brazilian YouTube Climate Discourse

Wenchao Dong, Marcelo S. Locatelli, Virgilio Almeida, Meeyoung Cha

Comments Published at the Special Track on AI for Social Impact at AAAI 2026

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英文摘要

Climate change poses a global threat to public health, food security, and economic stability. Addressing it requires evidence-based policies and a nuanced understanding of how the threat is perceived by the public, particularly within visual social media, where narratives quickly evolve through voices of individuals, politicians, NGOs, and institutions. This study investigates climate-related discourse on YouTube within the Brazilian context, a geopolitically significant nation in global environmental negotiations. Through three case studies, we examine (1) which psychological content traits most effectively drive audience engagement, (2) the extent to which these traits influence content popularity, and (3) whether such insights can inform the design of persuasive synthetic campaigns--such as climate denialism--using recent generative language models. Another contribution of this work is the release of a large publicly available dataset of 226K Brazilian YouTube videos and 2.7M user comments on climate change. The dataset includes fine-grained annotations of persuasive strategies, theory-of-mind categorizations in user responses, and typologies of content creators. This resource can help support future research on digital climate communication and the ethical risk of algorithmically amplified narratives and generative media.

2511.05834 2026-04-09 stat.OT

Impacts of Data Splitting Strategies on Parameterized Link Prediction Algorithms

Xinshan Jiao, Yuxin Luo, Yilin Bi, Tao Zhou

Comments 18 pages, 3 figures. Published in Physica A (2026)

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Journal ref
Physica A: Statistical Mechanics and its Applications, 692 (2026), 131545
英文摘要

Link prediction is a fundamental problem in network science, aiming to infer potential or missing links based on observed network structures. With the increasing adoption of parameterized models, the rigor of evaluation protocols has become critically important. However, a previously common practice of using the test set during hyperparameter tuning has led to human-induced information leakage, thereby inflating the reported model performance. To address this issue, this study introduces a novel evaluation metric, Loss Ratio, which quantitatively measures the extent of performance overestimation. We conduct large-scale experiments on 60 real-world networks across six domains. The results demonstrate that the information leakage leads to an average overestimation of about 3.6%, with the bias reaching over 15% for specific algorithms. Meanwhile, heuristic and random-walk-based methods exhibit greater robustness and stability. The analysis uncovers a pervasive information leakage issue in link prediction evaluation and underscores the necessity of adopting standardized data splitting strategies to enable fair and reproducible benchmarking of link prediction models.

2511.03956 2026-04-09 physics.flu-dyn math-ph math.MP

Thin gap approximations for microfluidic device design

Lingyun Ding, Terry Wang, Marcus Roper

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英文摘要

Over 125 years ago, Henry Selby Hele-Shaw realized that the depth-averaged flow in thin gap geometries can be closely approximated by two-dimensional (2D) potential flow, in a surprising marriage between the theories of viscous-dominated and inviscid flows. Hele-Shaw approximation allows visualization of potential flows over 2D airfoils and also undergirds important discoveries in the dynamics of interfacial instabilities and convection, yet it has found little use in modeling flows in microfluidic devices, although these devices often have thin gap geometries. Here, we derive a Hele-Shaw approximation for the flow in the kinds of thin gap geometries created within microfluidic devices. Using the Method of Weighted Residuals (MWR), we reinterpret the Hele-Shaw approximation as the leading term of an orthogonal polynomial expansion that can be systematically extended to higher-order corrections. The resulting leading-order equation coincides with the previously derived 2D approximations, but our derivation is shorter and more direct. By extending the expansion beyond leading order, we obtain a new reduced model that captures non-parabolic gap-wise velocity profiles and out-of-plane flow effects. We provide substantial numerical evidence showing that approximate equations can successfully model real microfluidic and inertial-microfluidic device geometries. By reducing three-dimensional (3D) flows to 2D models, our validated model will allow for accelerated device modeling and design.

2511.03894 2026-04-09 cond-mat.mes-hall cond-mat.quant-gas physics.optics

Measuring non-Abelian quantum geometry and topology in a multi-gap photonic lattice

Martin Guillot, Cédric Blanchard, Martina Morassi, Aristide Lemaître, Luc Le Gratiet, Abdelmounaim Harouri, Isabelle Sagnes, Robert-Jan Slager, F. Nur Ünal, Jacqueline Bloch, Sylvain Ravets

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英文摘要

Recent discoveries in semi-metallic multi-gap systems featuring band singularities have galvanized enormous interest in particular due to the emergence of non-Abelian braiding properties of band nodes. This previously uncharted set of topological phases necessitates novel approaches to probe them in laboratories, a pursuit that intricately relates to evaluating non-Abelian generalizations of the Abelian quantum geometric tensor (QGT) that characterizes geometric responses. Here, we pioneer the direct measurement of the non-Abelian QGT. We achieve this by implementing a novel orbital-resolved polarimetry technique to probe the full Bloch Hamiltonian of a six-band two-dimensional (2D) synthetic lattice, which grants direct experimental access to non-Abelian quaternion charges, the Euler curvature, and the non-Abelian quantum metric associated with all bands. Quantum geometry has been highlighted to play a key role on macroscopic phenomena ranging from superconductivity in flat-bands, to optical responses, transport, metrology, and quantum Hall physics. Therefore, our work unlocks the experimental probing of a wide phenomenology of multi-gap systems, at the confluence of topology, geometry and non-Abelian physics.