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2605.07684 2026-05-11 astro-ph.GA

The diverse morphologies and evolution of low-luminosity edge-brightened radio galaxies

B. Barkus, J. H. Croston, B. Mingo, M. J. Hardcastle, G. Gürkan, V. H. Mahatma

AI总结 该研究探讨了低光度边缘亮化射电星系(FRII类)的形态多样性及其演化特征,通过高分辨率的1.5 GHz VLA观测,对LOFAR巡天中选出的19个低光度FRII样本进行了详细分析。研究发现,这些低光度FRII在核心和热点分布上与传统高光度FRII相似,但表现出更高的核心比例和更复杂的活动特征,表明低光度FRII的动力学过程与高光度同类相似,但整体群体具有高度多样性。研究强调了在分析射电星系演化时,应谨慎使用二元形态分类,以更全面地理解喷流生命周期的复杂性。

Comments 16 pages, 7 figures, 8 tables. Accepted for publication in MNRAS

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英文摘要

Fanaroff-Riley class I (FRI) radio galaxies show centre-brightened emission from disrupted lower power jets, while traditionally more luminous class II (FRIIs), are edge-brightened, with relativistic jets terminating in hotspots. Population studies of radio-loud AGN (RLAGN) with low frequency, deep, wide-field surveys have revealed FRII-like radio structures at lower luminosities. We present the first high-resolution morphological investigation of a representative LOFAR-selected sample of low-luminosity FRIIs, to determine whether this new population is physically distinct from traditional high-luminosity FRIIs. Using new $1.5$-GHz Jansky Very Large Array (VLA) observations for a sample of 19 low-luminosity FRIIs, from the LOFAR Two Metre Sky Survey Data Release 1 (LoTSS DR1), with luminosities up to three orders of magnitude lower than the typical FR break ($L_{150} = 10^{26}$ W Hz$^{-1}$). We examine the compact features and perform spectral index analysis to identify hotspots, cores and signatures of restarting or remnant activity. We find a higher prevalence of cores and a comparable number of hotspots in the low-luminosity FRII sample compared to a randomly-selected sample of luminous ($L_{150}>10^{26}$ W Hz$^{-1}$) FRIIs selected from the same parent LOFAR sample. Approximately 32 per cent of low-luminosity FRIIs show restarting or remnant behaviour, while $\sim 32$ per cent are active FRIIs with compact hotspots. Our results show that FRII source dynamics occur at low radio luminosities, but reinforce earlier conclusions that the population of low-luminosity edge-brightened RLAGN is highly diverse. Binary morphological classifications should be used cautiously as a first step towards more nuanced investigations of the complexity of jet life cycles and evolution.

2605.07682 2026-05-11 math.DG math-ph math.MP math.RT

Virasoro extensions for diffeomorphisms with breaks

Anton Izosimov, Boris Khesin, Howard Xiao

AI总结 本文研究的是在有限个点处不光滑的圆周同胚变换,即“断点微分同胚”。这些变换不构成李群,但可以自然地组织成一个李群胚。作者构造了该群胚的一个非平凡的n维中心扩张,并指出当限制在光滑微分同胚时,该扩张退化为经典的Virasoro群。此外,还定义了相应的“断点Virasoro”李胚,作为圆周上带有n个断点的光滑向量场的非平凡n维中心扩张,从而推广了Virasoro代数。作为副产品,作者还研究了区间上的类似情形,构造了固定端点微分同胚的非平凡中心扩张及相关结构。

Comments 20 pages

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英文摘要

We study homeomorphisms of the circle that are smooth diffeomorphisms away from a finite set of $n$ points. These "broken diffeomorphisms" do not form a Lie group, but instead naturally assemble into a Lie groupoid. We construct an explicit nontrivial $n$-dimensional central extension of this groupoid, which restricts to the classical Virasoro group when confined to smooth diffeomorphisms. We further describe the associated "broken Virasoro" algebroid, defined as a nontrivial $n$-dimensional central extension of the Lie algebroid of vector fields on the circle that are smooth except at $n$ points. This construction generalizes the Virasoro algebra. As a byproduct, we analyze a related setting on an interval: we construct a nontrivial central extension of the Lie algebra of vector fields vanishing at the endpoints, together with the corresponding central extension of the group of diffeomorphisms fixing the endpoints. We also describe the associated Lie algebroid and groupoid obtained by allowing the endpoints to vary.

2605.07681 2026-05-11 physics.ins-det

Test-Beam Performance of the AstroPix Silicon Sensor for Imaging Calorimetry

Yoonha Hong, Jeongsu Bok, Geunpil An, Joonsuk Bae, Yunseul Bae, Regina Caputo, Yun Eo, Wooseok Ham, Woohyeon Heo, Yoonha Hong, Manoj Jadhav, Seo Yun Jang, Jinryong Jeong, Hyon-Suk Jo, Sylvester Joosten, Beomkyu Kim, Bobae Kim, Chong Kim, Dongguk Kim, Minsuk Kim, Shin Hyung Kim, Woojong Kim, Wonjun Ko, Changhui Lee, Hyungjun Lee, Jason Sang Hun Lee, Jongwon Lee, Kyeongpil Lee, Sehwook Lee, Sangwoo Park, Jaehyeok Ryu, Bogyeong Seo, Jessica Metcalfe, Minsub Shim, Junseop Shin, Hwidong Yoo, Maria Żurek, Sanghoon Lim

AI总结 AstroPix 是一种用于未来空间伽马射线探测任务的高压 CMOS 单片有源像素传感器,同时也被考虑用于未来电子-离子对撞机实验中的成像量能器。本文报告了在 KEK 和 CERN 测试束流中对 AstroPix 第三代原型 AstroPix-v3 的性能评估结果,展示了其在高能电子和强子束流下的稳定表现及成像能力。实验表明,AstroPix-v3 能有效捕捉电磁簇射的发展过程,并通过切连科夫粒子识别技术实现电磁与强子簇射的区分,验证了其作为高精度成像层在下一代量能器中的适用性。

Comments 9 pages, 9 figures

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AstroPix is a high-voltage CMOS HVCMOS monolithic active pixel sensor MAPS developed for future space-based gamma-ray missions. It is also a candidate technology for the imaging layer of the Barrel Imaging Calorimeter BIC in the ePIC experiment at the future Electron-Ion Collider EIC. We report the first AstroPix test-beam results obtained at the KEK Photon Factory Advanced Ring PF-AR and the CERN Proton Synchrotron PS T10 beam line in 2025, using the third prototype AstroPix-v3. AstroPix-v3 sensors were operated as both standalone tracking layers and imaging layers interleaved with prototype lead/scintillating-fiber Pb/SciFi calorimeter modules, using electron and hadron beams in the few-GeV/c momentum range. Event synchronization between the continuous readout of AstroPix-v3 and the trigger-based readout of the Pb/SciFi calorimeter was achieved using a common timestamp. The AstroPix-v3 sensors exhibit stable performance, reaching a maximum hit efficiency of 68 percent at a bias voltage of -400 V under pion-dominated beam conditions. When combined with the Pb/SciFi calorimeter, the AstroPix layers successfully capture the development of electromagnetic showers. Using Cherenkov-based particle identification, electron-induced events exhibit significantly higher hit multiplicities and broader spatial distributions than pion-induced events, thereby providing clear discrimination between electromagnetic and hadronic showers. These results demonstrate that AstroPix-v3 provides effective, high-granularity imaging of shower development and is well suited as an imaging layer in future calorimeter systems for both collider and space-based experiments.

2605.07680 2026-05-11 astro-ph.HE

Advance warning of $γ$-ray blazar flares from \textit{Fermi}-LAT light curves: a strictly causal machine-learning backtest

Zahir Shah, Sikandar Akbar

AI总结 该研究利用费米卫星的长期伽马射线观测数据,构建了一个严格因果的机器学习框架,用于提前预测耀变体爆发。通过贝叶斯块方法识别爆发区间,并从光变曲线中提取42个可变性特征,分别训练了用于预测未来90天和45天内爆发的WATCH和TRIGGER模型。实验表明,多项式逻辑回归模型在预测性能上表现最佳,能够在爆发前数天发出预警,展示了光变曲线中蕴含的预测爆发信息价值。

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英文摘要

Long-term \textit{Fermi}-LAT monitoring makes it possible to ask whether a blazar light curve shows signs of an upcoming flare before the flare becomes obvious in the $γ$-ray emission. We present a strictly causal machine-learning framework for forecasting $γ$-ray blazar flares from 3-d binned LAT light curves. Flare intervals are identified with Bayesian Blocks, and each light curve is sampled with 365-d trailing windows from which 42 variability features are measured. We train separate WATCH and TRIGGER models: WATCH predicts whether flare activity will appear within the next 90 d, while TRIGGER predicts whether a new flare onset will occur within the next 45 d. To avoid temporal leakage, all scaling, calibration, threshold selection, and validation use only the pre-cutoff data before MJD 60000. We apply the method to the FSRQ 4FGL\,J1048.4$+$7143, using 13 bright blazars as auxiliary training sources. Among logistic regression, polynomial logistic regression, and random forest classifiers, polynomial logistic regression gives the strongest held-out WATCH performance, with ROC AUC $=0.891$, average precision $=0.396$, and a block-permutation probability $p_{\rm perm}=0.006$. At the selected WATCH threshold, it recovers 18 of the 21 positive windows in the held-out WATCH set, corresponding to a recall of 0.86. The same model also gives the best held-out TRIGGER ranking, with TRIGGER AUC $=0.770$ and TRIGGER AP $=0.123$, although no reliable pre-onset TRIGGER alert is obtained. The WATCH state appears before both held-out flare episodes, with final alerts 4.5 and 2.5 d before onset. The corresponding broader WATCH-active periods begin 88.5 and 72.5 d before flare onset. These results suggest that long-term {\fermi} light curves contain useful predictive information about the build-up to blazar flares.

2605.07679 2026-05-11 math.CO

On uniform Higmanian association schemes

Grigory Ryabov

AI总结 本文研究了秩为5的非本原对称不可分解关联方案,特别关注具有两个非平凡旁系的Higmanian关联方案的均匀性条件。作者给出了这类方案为均匀的充要条件,并构造了若干均匀的Higmanian Cayley 方案,为该领域的理论发展提供了新的例子和判断依据。

Comments 12 pages

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An imprimitive symmetric indecomposable association scheme of rank $5$ is said to be Higmanian. In the present paper, we prove a necessary and sufficient condition for a Higmanian association scheme with two nontrivial parabolics to be uniform. We also provide examples of uniform Higmanian Cayley schemes.

2605.07678 2026-05-11 cs.SE

Characterizing and Mitigating False-Positive Bug Reports in the Linux Kernel

Jiashuo Tian, Dong Wang, Chen Yang, Haichi Wang, Zan Wang, Junjie Chen

AI总结 本文研究了Linux内核开发中常见的误报错误报告问题,即正确系统行为被错误标记为缺陷的情况。通过手动构建包含2006个错误报告的数据集,分析发现误报消耗了与真实错误相当的开发者资源,并主要集中在文件系统和驱动模块中。为解决此问题,作者评估了大语言模型在自动识别和缓解误报中的应用,其中检索增强生成(RAG)方法表现出色,达到91%的召回率和88%的F1分数,展示了LLMs在提升Linux内核错误处理效率中的潜力。

Comments Accepted in the Research Track in FSE 2026

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False-positive bug reports represent a significant yet underexplored challenge in the development and maintenance of the Linux kernel. They occur when correct system behavior is mistakenly flagged as a defect, consuming developer effort without leading to actual code improvements. Such reports can mislead developers, waste debugging resources, and delay the resolution of real bugs. In this paper, we present the first comprehensive empirical study of false-positive bug reports in the Linux kernel. We manually construct a dataset of 2,006 bug reports comprising 1,509 genuine bugs and 497 false positives collected from Bugzilla and Syzkaller. Our analysis indicates that false positives demand effort comparable to real bugs, often requiring extended discussions and non-trivial closure time. They occur in several components, especially File Systems and Drivers, mainly due to external dependencies and semantic misunderstandings. To address this challenge, we evaluate large language models (LLMs) for automated false-positive bug report mitigation. Among various prompting strategies, retrieval-augmented generation (RAG) performs best, achieving 91% recall and an F1 score of 88%. These findings highlight the non-negligible cost of false positive bug reports and show the promise of LLMs for more efficient false positive mitigation in the Linux kernel.

2605.07673 2026-05-11 math.CA math.AP math.CV

Hermite expansions of functions from the weighted Hardy class

Satyajyoti Achar, Manish Chaurasia, Ramesh Manna

AI总结 本文研究了一类具有高斯衰减和指数增长特性的加权Hardy空间中的函数,分析了其Hermite展开的性质。通过研究对数型权重,建立了函数Hermite系数的衰减估计,并结合Hermite函数的渐进行为,证明了谐振子薛定谔方程解的衰减速率。此外,还分析了Laguerre展开和短时傅里叶变换,证明了Hermite投影算子在这些空间中的指数衰减,并对次临界Hardy不确定性原理进行了改进。

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In this paper, we analyze a function space consisting of functions for which both the function and its Fourier transform exhibit Gaussian decay together with exponential growth governed by suitable weight functions. First, we examine logarithmic-type weights, in which case these function spaces are equivalent to Pilipović spaces. In this setting, we establish a decay estimate for the Hermite coefficients of functions. Furthermore, by combining these estimates with the asymptotic behavior of Hermite functions, we prove a decay rate for solutions to the harmonic oscillator Schrödinger equation. Second, we consider a class of weights and prove the exponential decay of the Hermite projection operators on these spaces by analyzing Laguerre expansions and the short-time Fourier transform. Additionally, we revisit the subcritical Hardy uncertainty principle and obtain a partial improvement toward a conjecture posed by Vemuri.

2605.07672 2026-05-11 math.CO

On separability of Tatra association schemes

Grigory Ryabov

AI总结 本文研究了由有限域乘法群子群定义的对称双线性形式所诱导的Tatra关联方案的可分离性问题。作者证明了每个Tatra关联方案都是2-可分离的,即其同构类由其二维交集数的张量唯一确定。这一结果为理解此类关联方案的结构提供了重要的代数刻画。

Comments 10 pages

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A Tatra association scheme is an association scheme arising from a symmetric bilinear form defined on the equivalence classes of nonzero $2$-dimensional vectors modulo some subgroup of the multiplicative group of a finite field. In the present paper, we prove that every such association scheme is $2$-separable, i.e. it is determined up to isomorphism by the tensor of its $2$-dimensional intersection numbers.

2605.07670 2026-05-11 cond-mat.mtrl-sci

Harnessing Structural Disorder: Unraveling Hydrogen Evolution in Monolayer Amorphous Carbon via First-Principles Simulations and Machine-Learned Potentials

Sreehari M S, Ashutosh Krishna Amaram, Raghavan Ranganathan

AI总结 该研究通过第一性原理计算和机器学习势模型,系统探究了单层非晶碳(MAC)在析氢反应(HER)中的催化性能,并与石墨烯等晶体碳材料进行对比。研究发现,MAC中丰富的五元、六元和七元环结构以及局部无序特性,使其在HER中表现出更广的吉布斯自由能变化范围,并具有优化活性位点的潜力。研究还表明,七元环、曲率和波纹高度等因素对HER活性有显著促进作用,为设计高性能非晶碳催化剂提供了理论指导。

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Disorder and defective coordination in the catalytic plane are crucial for enhancing the Hydrogen Evolution Reaction (HER) on two-dimensional catalysts. Amorphous materials are disordered, making them catalytically adaptive for many reactions. In this work, the HER capabilities of Monolayer Amorphous Carbon (MAC) were studied in comparison with crystalline carbon derivatives, such as pristine graphene (GE) and graphyne derivatives. MAC generated from melt-quench simulations revealed a diverse framework of predominantly sp2 and sp3 carbons with numerous 5-, 6-, and 7-membered rings. Density Functional Theory (DFT) calculations investigated free-energy variations in hydrogen adsorption for each material. According to Sabatier's principle, optimum activity is achieved when the Gibbs free energy (Delta GH) change approaches zero. Crystalline carbon materials possess limited active sites, with beta-graphyne showing the best Delta GH value of +0.34 eV. The adsorption study for MAC was conducted in 30 distinct local environments, where core structural properties were analyzed against varying radii. Calculations showed a Delta GH distribution for MAC ranging from -0.02 eV to +1.35 eV. To evaluate activity across the entire MAC surface, a MACE MLIP foundation model was finetuned, achieving optimal energy and force fitting of 1.67 meV/atom and 29.15 meV/A, respectively. The MLIP predicted Delta GH values from -0.91 eV to +1.70 eV, with approximately 15% of sites exhibiting values below +0.25 eV. Feature analysis revealed that 7-membered rings, curvature, and ripple height enhance HER activity. Our findings suggest that, with careful optimization of local features, MAC can be tuned to compete with noble metal catalysts.

2605.07669 2026-05-11 math.AP

The Cauchy problem for the improved Boussinesq equation with spatially quasi-periodic initial data

Zhiqiang Wan, Wenji Wu, Heng Zhang

AI总结 本文研究了改进型Boussinesq方程在实数线上具有空间准周期初始数据的柯西问题。作者针对非共振频率向量,证明了在两个傅里叶空间类中存在唯一性经典的准周期解,并保持相同的频率向量。对于指数衰减和多项式衰减的初始傅里叶系数,分别得到了相应衰减性质在时间区间内保持的准周期解,并将结果推广到更高次非线性项 $u^p$ 的情形。

Comments 33 Pages, 1 Figure

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We study the Cauchy problem for the improved Boussinesq equation \[ u_{tt}-u_{xx}-u_{xxtt}-(u^2)_{xx}=0 \] on the real line with spatially quasi-periodic initial data. For a non-resonant frequency vector $ω\in\mathbb R^ν$, we prove local existence and uniqueness of classical spatially quasi-periodic solutions with the same frequency vector $ω$ in two Fourier-side classes. First, for exponentially decaying initial Fourier coefficients, we obtain a spatially quasi-periodic solution whose Fourier coefficients remain exponentially decaying on an explicit time interval. Second, for initial Fourier coefficients $c(n)$ and $d(n)$ satisfying the polynomial decay $ |c(n)|+|d(n)|\lesssim (1+|n|)^{-r}, \; r>ν+2, $ we prove that the corresponding spatially quasi-periodic solution preserves the same polynomial decay rate as the initial data. We also extend these results to the nonlinearity $u^p$ with integer $p \geq 3$.

2605.07668 2026-05-11 quant-ph

Bridging Krylov Complexity and Universal Analog Quantum Simulator

Shuo Zhang, Yuzhi Tong, Pengfei Zhang, Zeyu Liu

AI总结 本文研究了如何在模拟量子系统中定量评估实现特定量子操作的复杂性,提出了广义Krylov复杂度作为衡量这一复杂性的新指标。通过构建由一组哈密顿量生成的块Krylov基,该方法能够有效组织模拟器原生相互作用及其嵌套交换作用所生成的操作空间。研究还表明,目标操作的广义Krylov复杂度可作为预测其在模拟器中实现所需最短时间的有力指标,为设计高效的模拟控制协议提供了直观而实用的工具。

Comments 9 pages, 4 figures

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Quantum simulation of complex many-body systems beyond classical computational capabilities provides a promising route toward understanding novel quantum phases and their transitions. In particular, analog quantum simulators with global control fields have attracted considerable attention due to their potential to simulate arbitrary Hamiltonians and perform quantum computing tasks. However, a clear, quantitative measure for the complexity of implementing specific quantum operations in such systems is still lacking. In this Letter, we address this challenge by introducing generalized Krylov complexity, a concept originating from operator growth dynamics, as a direct diagnosis for this synthesis complexity. We construct the block Krylov basis generated by a set of Hamiltonians, which naturally organizes the operator space achievable through the simulator's native interactions and their nested commutators. By analyzing representative systems including Rydberg atom arrays, we demonstrate that the generalized Krylov complexity of a target operation serves as a strong predictor of the minimum time required for its realization. Our results establish Krylov complexity as an intuitive and predictive tool for designing efficient control protocols in analog quantum simulators.

2605.07667 2026-05-11 math.CA

Dyadic Martingale Transforms and Weighted Walsh-Carleson Operators

Ushangi Goginava, Farrukh Mukhamedov

AI总结 本文研究了与Walsh-Fourier部分和相关的二元鞅变换所引发的加权Walsh-Carleson极大算子。在满足统一的二元变分条件和顶阶二元尺度上界条件的权重下,作者证明了沿子序列的相应极大算子的弱型$(1,1)$估计,并给出了与权重在顶阶二元尺度附近行为相关的发散判据。研究还应用到Walsh-Fourier部分和的矩阵变换,包括de la Vallée Poussin平均、变参数Cesàro平均、Nörlund对数平均等,并证明了Walsh-Paley版本的Leindler-Tandori定理及多种求和方法的处处发散结果。

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We study weighted Walsh--Carleson maximal operators arising from dyadic martingale transforms associated with Walsh--Fourier partial sums. For weights satisfying a uniform dyadic variation condition and a uniform bound at the top dyadic scale, we prove weak type~$(1,1)$ estimates for the corresponding maximal operators along subsequences. We also give divergence criteria in terms of the behavior of the weights near the top dyadic scale and, under suitable admissibility assumptions, relate these criteria to explicit ratio conditions. As applications, we obtain results on matrix transforms of Walsh--Fourier partial sums, including de la Vallée Poussin means, Cesàro means with varying parameters, Nörlund logarithmic means, and general Nörlund means. In particular, we prove a Walsh--Paley analogue of the Leindler--Tandori theorem and establish everywhere divergence results for several summability methods.

2605.07666 2026-05-11 math.RA math.FA

Commutativity preserving mappings in Banach algebras

M. Brešar, G. M. Escolano, A. Peralta, A. R. Villena

AI总结 本文研究了在满足特定条件的巴拿赫代数之间保持交换性的映射的结构。作者证明了若一个满的加法映射使得每个元素的平方像与其自身像交换,则该映射可表示为一个加法同态或反同态的直接和与中心元素的线性组合。这一结果揭示了此类映射的代数结构特征,为巴拿赫代数理论提供了新的见解。

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Let $A$ and $B$ be unital complex Banach algebras having no quotients isomorphic to $\mathbb{C}$ or $M_2(\mathbb{C})$. Assume additionally that $B$ is semisimple. If a surjective additive mapping $Φ\colon A\to B$ satisfies $[Φ(x^2),Φ(x)] = 0$ for all $x\in A$, then there exist a surjective direct sum of an additive homomorphism and an additive anti-homomorphism $Ψ\colon A\to B$, an invertible element $λ\in\mathcal{Z}(B)$, and an additive mapping $ζ\colon A\to\mathcal{Z}(B)$ such that $Φ(x)=λΨ(x)+ζ(x)$ for all $x\in A$.

2605.07664 2026-05-11 math.CO

Benjamini-Schramm convergence and subtrees of trees

Stijn Cambie, Stephan Wagner, Ruoyu Wang

AI总结 本文研究了一类在Benjamini-Schramm意义下收敛的树序列的子树数量及其密度的渐进行为。作者证明,当树序列收敛时,子树熵(即子树数量的对数除以树的规模)会收敛到仅由极限树决定的常数,类似地,子树密度在排除极限中存在长路径的情况下也具有相同的收敛性质。此外,研究还表明子树密度和平均子树熵在单位区间内对一般树和简化树分别具有稠密性。

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In this paper, we study the asymptotic behaviour of the number of subtrees and the subtree density for a sequence of trees that converges in the Benjamini-Schramm sense. Benjamini-Schramm convergence, also called local weak convergence, describes the local behaviour of a sequence of graphs. Here we show that for a Benjamini-Schramm-convergent sequence of trees, the subtree entropy, i.e., the logarithm of the number of subtrees divided by the order, converges to a constant depending only on the limit. The same holds true for the subtree density, i.e., the probability of a uniformly random vertex being contained in a uniformly random subtree, provided that long paths are ruled out in the limit. Related to this, we show that the subtree density and the average subtree entropy are dense in different parts of the unit interval $[0,1]$ for both general trees and series-reduced trees.

2605.07659 2026-05-11 math-ph math.MP

Superintegrability in the interaction of two particles with spin: First-order pseudo-scalar integrals of motion

Fatih Turkkan, O. Ogulcan Tuncer, I. Yurdusen

AI总结 本文研究了两个非相对论性自旋-$1/2$粒子在三维欧几里得空间中相互作用的量子超可积系统,重点探讨了具有第一阶伪标量运动积分的系统。通过构建最一般的旋转不变哈密顿量,并构造相应的第一阶伪标量算符,作者推导出一组确定方程并求解,从而对这类超可积系统进行了完整分类,并确定了对应的伪标量运动积分。该研究发现了新的依赖自旋的超可积系统家族,丰富了与核子-核子相互作用相关的可积模型,并为分类具有自旋的量子超可积系统提供了重要进展。

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英文摘要

In recent work, we initiated a research program aimed at the systematic investigation of quantum superintegrable systems describing the interaction of two non-relativistic spin-$1/2$ particles in three-dimensional Euclidean space. In that study, we classified all such superintegrable systems admitting additional first-order scalar integrals of motion. In the present paper, we continue this program by focusing on systems that admit additional pseudo-scalar integrals of motion. Starting from the most general rotationally invariant Hamiltonian for two interacting spin-$1/2$ particles, we construct the most general first-order pseudo-scalar operator in the form of a matrix polynomial in the momenta. Imposing the commutativity of this operator with the Hamiltonian leads to a system of determining equations. By solving these equations, we obtain a complete classification of such superintegrable systems and determine the corresponding pseudo-scalar integrals of motion. The resulting classification provides new families of superintegrable systems with spin-dependent interactions. These systems enrich the class of integrable models relevant to nucleon--nucleon interactions and contribute to the broader program of classifying superintegrable quantum systems with spin. For selected cases, we further construct the associated polynomial symmetry algebras generated by the integrals of motion, providing additional insight into the algebraic structure of the systems.

2605.07658 2026-05-11 eess.SY cs.SY

Spatiotemporal Trust Evaluation for Collaborator Selection via Customized GNN-Mamba

Botao Zhu, Xianbin Wang

AI总结 本文研究了如何在协作任务中有效选择可信的合作者,提出了一种基于定制化图神经网络与Mamba模型的时空信任评估方法。该方法结合历史协作中的空间信任关系与设备在特定任务下的资源能力评估,能够准确捕捉设备信任的短期波动与长期演化。实验表明,该模型在信任评估的准确性与稳定性方面优于现有方法。

Comments IEEE ICC 2026

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英文摘要

The successful completion of collaborative tasks relies on the effective selection of trustworthy collaborators. To accurately evaluate the trustworthiness of potential collaborators, it is necessary to combine insights from their past collaborations with assessments of their resource capabilities under specific task contexts. However, the coexistence of diverse trust perspectives, along with complex spatiotemporal dependencies among devices, makes accurate trust evaluation particularly challenging. To address these challenges, we propose a customized Graph Neural Network (GNN)-Mamba (GM) model for trust evaluation and collaborator selection. In this model, the GNN model performs spatial trust fusion by leveraging inter-device spatial dependencies extracted from historical collaborations, while the Mamba-based temporal model captures both short-term fluctuations and long-term evolution of device trust. In addition, task-specific resource trust is incorporated to reflect the practical capabilities of devices under varying task conditions. Experimental results demonstrate that the proposed GM model outperforms baseline approaches in terms of the accuracy and stability of trust evaluation.

2605.07657 2026-05-11 eess.SY cs.SY

Electric Axle and Wheel Module Driveline Concepts for Self-propelled Agricultural Machinery and Equipment Carriers

Timo Oksanen, Karl Th. Renius

AI总结 本文研究了用于自推进农业机械和设备运输车的电动驱动轴和轮模块概念,旨在提升底盘和悬挂系统设计的自由度并降低能量损耗。研究对比了轴模块和轮模块在负载、效率、转向性、可控性等方面的性能,指出轮模块在设计灵活性和冗余性方面具有优势,而轴模块则在成本和结构刚性方面更具优势。两种模块均集成了分布式控制和转向功能,只需车辆提供直流电源和通信接口即可实现协同工作。

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Journal ref
Technical University of Munich. 2026. ISBN 978-3-911430-15-9. https://mediatum.ub.tum.de/1854369
英文摘要

Direct electric drivelines without power-split open new design freedom for frame and suspension design, along with often lower energy losses. This paper focuses on self-propelled agricultural machinery (combine and forage harvest-ers, root crop harvesters), equipment carriers, propelled trailers and field robots. For a typical vehicle with four driven wheels, the electric motors can be packaged as two axle modules or four wheel modules, both defined herein as self-contained mechatronic units with integrated power electronics, distributed control intelligence and steering. Axle module and wheel module concepts are compared in detail against engineering requirements including loads, effi-ciency, steerability, controllability, braking, suspension, structural load support, asymmetric wheel loading and manu-facturing cost. The wheel module offers maximum design freedom, redundancy and controllability, while the axle module provides lower cost, structural rigidity, automatic load sharing through the differential and the ability to be used in existing vehicle structures. Both concepts are defined such that distributed control intelligence and steering are integral to each unit, requiring only a DC power bus and communication interface from the vehicle.

2605.07656 2026-05-11 cond-mat.supr-con cond-mat.str-el

Finite temperature pair density wave superconductivity in $d$-wave altermagnets

Amrutha N Madhusuthanan, Madhuparna Karmakar

AI总结 本文研究了在二维$d$-波反铁磁材料中实现有限动量超导性的机制。通过非微扰的静态路径近似蒙特卡洛方法,作者发现$d$-波反铁磁态能够稳定支持一种具有有限动量的配对密度波(PDW)超导态,并在一定温度范围内抵抗热涨落的影响。该机制源于动量依赖的自旋劈裂效应,能够在无外加Zeeman场的情况下增强有限中心动量的配对不稳定性,为实现热稳定性良好的有限动量超导提供了新的途径。

Comments 13 pages, 10 figures. This manuscript supersedes arXiv:2603.25314

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英文摘要

We demonstrate that altermagnetism provides a field-free mechanism for stabilizing finite-momentum superconductivity in two dimensions. Using a non-perturbative static path approximation Monte Carlo approach, we show that a d-wave altermagnet supports a robust pair-density-wave (PDW) phase that persists over a finite temperature window despite strong thermal fluctuations. The underlying mechanism originates from momentum-dependent spin splitting, which effectively enhances pairing instabilities at finite center-of-mass momentum without Zeeman fields. We identify distinct thermal scales associated with phase coherence, gap closing, and pseudogap formation, and establish characteristic spectroscopic and real-space signatures of the PDW state. Our results reveal altermagnetism as a robust route to thermally stable finite-momentum superconductivity and provide experimentally testable signatures for altermagnetic materials.

2605.07652 2026-05-11 astro-ph.EP astro-ph.GA

Origin and evolution of NiI and FeI in the coma of the interstellar comet 3I/ATLAS throughout its trajectory

Damien Hutsemékers, Jean Manfroid, Cyrielle Opitom, Emmanuël Jehin, Aravind Krishnakumar, Fernando Massa Fernandes, Michele Bannister, Dennis Bodewits, Rosemary Dorsey, Fiorangela La Forgia, Brian Murphy

AI总结 本研究通过高分辨率的UVES+VLT观测,分析了星际彗星3I/ATLAS在近日点之后彗发中中性镍和铁原子的产生与演化。研究发现其金属产生率远高于典型太阳系彗星,并表现出明显的不对称性,镍与铁的丰度比在近日点后逐渐趋于太阳系彗星的水平。研究提出并扩展了羰基化合物光解离假说,解释了观测到的金属产生速率和镍/铁比值,表明镍羰基化合物的挥发性更高,且彗星核内部可能存在浅温度梯度和额外的瞬时热源。

Comments Submitted to A&A

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英文摘要

We present high-resolution UVES+VLT observations of neutral nickel and iron atoms in the coma of the interstellar comet 3I/ATLAS taken after perihelion. Metal emission was strong shortly after perihelion and persisted at large heliocentric distances. At $r_h \sim 2$ au the total metal production rate was found to be at least an order of magnitude larger than that of typical solar-system comets. Post-perihelion production rates exhibit pronounced asymmetry compared to the pre-perihelion behavior: production rates are higher after perihelion and decline more gradually with $r_h$, the difference being stronger for FeI. The NiI/FeI abundance ratio, initially anomalously large before perihelion, evolved toward values comparable to solar-system comets near 2 au, and shows a weaker $r_h$ dependence after perihelion. To interpret these results, we revisited and extended the carbonyl hypothesis in which FeI and NiI are produced by the rapid photodissociation of Fe(CO)$_5$ and Ni(CO)$_4$ vaporized from the nucleus. Fits that include direct sublimation of carbonyls reproduce the observed rates and the high NiI/FeI line ratio, which is determined by the higher volatility of Ni(CO)$_4$. Desorption of carbonyls from sublimating CO$_2$ and H$_2$O ices is found to be negligible. The temperature profiles needed to reproduce the observations were found to be shallower than the equilibrium $T \propto r_h^{-1/2}$ relation, suggesting that the sublimation could occur below the surface of the nucleus. Fits using temperature profiles from thermal models require sublimation from depths of several cm, especially post-perihelion. An additional transient heat source ($T \simeq$ 100-140~K), possibly linked to the amorphous-crystalline ice transition, is proposed to explain the early NiI excess before perihelion.

2605.07651 2026-05-11 hep-ph

Conditions for boundedness from below of a $Δ(54)$-symmetric three-Higgs-doublet model

Darius Jurčiukonis, Luís Lavoura

AI总结 本文研究了一个具有 $Δ(54)$ 对称性的三希格斯二重态模型中标量势的轨道空间,分析了其下界有界性的条件。研究发现,若势能具有 $CP$ 对称性,则其三维轨道空间为多面体;若无 $CP$ 对称性,则四维轨道空间的边界有时略微凹陷,但似乎从未凸起。基于此,作者提出了势能下界有界的必要且充分条件,并通过大量势能的暴力最小化验证了该猜想的正确性。

Comments 11 pages, 2 figures

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英文摘要

We investigate the orbit space of the scalar potential of a $Δ(54)$-symmetric three-Higgs-doublet model. We find that, if the potential enjoys $CP$ invariance, then its three-dimensional orbit space is a polytope; if the potential has no $CP$ symmetry, then its four-dimensional orbit space has a boundary that is sometimes slightly concave, but seems never to be convex. Consequently, we conjecture necessary and sufficient conditions for the potential to be bounded from below; brute-force minimization of a large number of potentials affirms the accuracy of our conjecture. We list all possible charge-conserving and charge-breaking minima of the potential.

2605.07645 2026-05-11 math.AG

Root bounds of vertical systems using tropical geometry

Elisenda Feliu, Paul Alexander Helminck, Oskar Henriksson, Yue Ren, Benjamin Schröter, Máté L. Telek

AI总结 本文研究了具有垂直系数依赖的稀疏多项式系统在复数域和正实数域上的根数上界问题。作者利用热带几何方法,将这类系统的复根数量与热带线性空间和经典线性空间的交数联系起来,并在特定情况下将其表示为混合体积。此外,作者还给出了正实根数量的上下界,特别地,当正根具有环状结构时,提供了更简洁的上界估计,相关算法已在Julia中实现。

Comments 30 pages, 3 figures. Comments welcome!

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英文摘要

Sparse polynomial systems with vertical coefficient dependencies arise naturally when describing the critical points of optimization problems and, when augmented with linear forms, the steady states of chemical reaction networks. Moreover, any polynomial system is the specialization of such a parametrized system. We prove that the generic number of complex zeros of an augmented vertically parametrized system is the tropical intersection number of a tropical linear space and a classical linear space. In the special case when the matroid of the tropical linear space is cotransversal, we express this number as a mixed volume. We also obtain bounds on the maximal number of positive zeros, which is often the significant number in applications. We derive lower bounds from the number of intersections between positive tropicalizations, and when the positive zeros have toric structure, we provide upper bounds that are simpler and in some cases smaller than the generic root count. The resulting algorithms are implemented in Julia.

2605.07644 2026-05-11 cs.DS

Faster Deterministic Streaming Vertex Coloring

Shiri Chechik, Hongyi Chen, Tianyi Zhang

AI总结 本文研究了图着色问题在半流模型下的确定性算法,目标是以少量颜色对图进行着色,同时仅使用 $\tilde{O}(n)$ 的内存。此前研究表明,确定性算法在单次遍历中需要指数级颜色,而随机算法可在一次遍历中实现 $(Δ+1)$-着色。本文提出了一种新的确定性半流算法,能够在 $O(\sqrt{\log Δ})$ 次遍历中实现 $O(Δ)$-着色,首次在次对数遍历次数下实现了与 $Δ$ 线性相关的调色板大小的确定性着色。

Comments To appear in ICALP 2026

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英文摘要

Graph coloring is a fundamental problem in computer science. In the semi-streaming model, an input graph $G$ on $n$ vertices and maximum degree $Δ$ is presented as a stream of edges, and the goal is to compute a vertex coloring using a small number of colors while storing only $\tilde{O}(n)$ bits of memory. Recent work has revealed an exponential separation between randomized and deterministic approaches in this setting: while randomized algorithms can achieve a $(Δ+1)$-coloring in a single pass [Assadi, Chen, and Khanna, 2019], any single-pass deterministic algorithm requires $\exp(Δ^{Ω(1)})$ colors [Assadi, Chen, and Sun, 2022]. Consequently, deterministic algorithms that use few colors must necessarily make multiple passes over the stream. Prior to this work, the best known deterministic trade-offs were: an $O(Δ^2)$-coloring in 2 passes, an $O(Δ)$-coloring in $O(\log Δ)$ passes [Assadi, Chen, and Sun, 2022], and a $(Δ+1)$-coloring in $O(\log Δ\cdot \log\log Δ)$ passes [Assadi, Chakrabarti, Ghosh, and Stoeckl, 2023]. It remained open whether better trade-offs -- particularly with sub-logarithmic pass complexity and linear-in-$Δ$ palette size -- were achievable. In this paper, we present a new deterministic semi-streaming algorithm that computes an $O(Δ)$-coloring in $O(\sqrt{\log Δ})$ passes. This is the first deterministic streaming algorithm to achieve a coloring with palette size linear-in-$Δ$ using sublogarithmic-in-$Δ$ passes.

2605.07643 2026-05-11 cond-mat.mes-hall

Bias-Engineered Synthetic Antiferromagnets Hosting sub-20 nm Zero-Field Skyrmions at Room Temperature

Emily Darwin, Riccardo Tomasello, Reshma Peremadathil Pradeep, Mario Carpentieri, Giovanni Finocchio, Hans J. Hug

AI总结 该研究提出了一种新型的合成反铁磁(SAF)偏置系统,用于在零磁场下稳定亚20纳米尺度的反铁磁斯格明子(SAFsk),并在室温下实现其可控生成。通过设计和集成多层结构,并结合预处理磁场循环,实现了对斯格明子极性和稳定性的精确调控。该方法不仅克服了零场下斯格明子稳定性的难题,还为未来斯格明子器件的规模化应用提供了可靠且可扩展的解决方案。

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英文摘要

Synthetic antiferromagnetic skyrmions (SAFsk) are nanoscale, topologically protected spin textures with strong potential for spintronic technologies because of their high stability and the absence of the skyrmion Hall effect. However, robust zero field stabilization remains a central challenge. Here, a synthetic antiferromagnetic (SAF) bias system is introduced as a novel strategy to stabilize both ferromagnetic skyrmions (FMsk) and SAFsk at zero field. Ferromagnetic (FM) and SAF multilayers are designed, fabricated and integrated with the SAF bias system to enable controlled skyrmion stabilization and polarity setting via multilayer design and a preparatory field cycle. Combining quantitative and high-sensitivity magnetic force microscopy (MFM) with micromagnetic modeling, reliable zero field skyrmion formation is demonstrated and sub 20nm SAFsk are directly observed, the smallest SAFsk reported to date. Moreover, the SAF bias system concept introduced here offers a robust and scalable route to bias future skyrmion multilayers, as its compensated nature suppresses domain formation and preserves a uniform exchange field.

2605.07641 2026-05-11 astro-ph.HE

KM3-230213A and potential astrophysical sources

Per Arne Sevle Myhr

AI总结 KM3NeT/ARCA 最近探测到超高能中微子 KM3-230213A,这是首个能量超过 100 PeV 的天体物理中微子,为研究超高能宇宙开辟了新的窗口。该研究综述了当前超高能中微子的观测现状,并探讨了该事件与 IceCube 和 Pierre Auger 实验现有限制之间的矛盾。同时,文章分析了可能的天体物理来源,并利用推断的弥漫中微子通量对潜在源群体的特性进行了约束。

Comments Contribution to the 2026 Very High Energy Phenomena in the Universe session of the 60th Rencontres de Moriond

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英文摘要

The recent detection of the ultra-high energy neutrino KM3-230213A by KM3NeT/ARCA marks the first observation of an astrophysical neutrino with energy above 100 PeV, opening a new window to the ultra-high energy Universe. In this contribution, the current global ultra-high energy neutrino landscape in light of this event is reviewed, including tension of this observation with existing limits set by the IceCube and the Pierre Auger Observatories. Different scenarios are discussed to explain its origin. Recent efforts to constrain features of potential source populations using the inferred diffuse ultra-high energy neutrino flux are also presented.

2605.07638 2026-05-11 math.AG math.AT

Relative $\mathbb{A}^1$-Contractibility of Smooth Schemes

Adrien Dubouloz, Krishna Kumar Madhavan Vijayalakshmi, Paul Arne Østvær

AI总结 本文研究了在非稳定 $\mathbb{A}^1$-同伦范畴中具有 $\mathbb{A}^1$-收缩性质的光滑态射,并证明在有限 Krull 维数的基概形上,此类态射的 $\mathbb{1}$-收缩性是纤维性质,即当且仅当所有几何纤维都是 $\mathbb{A}^1$-收缩的。文章进一步应用该结论于 $\mathbb{A}^n$-纤维空间,给出了其 $\mathbb{A}^1$-收缩性的几何刻画,并在低维情形下建立了刚性结果,同时构造了正特征和混合特征下的反例,并提出了关于奇异 $\mathbb{A}^1$-收缩曲面存在的开放问题。

Comments 22 pages; Comments welcome!

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英文摘要

We study smooth morphisms $f \colon X \to S$ that are $\mathbb{A}^1$-contractible in the unstable $\mathbb{A}^1$-homotopy category $\mathcal{H}(S)$. For base schemes $S$ of finite Krull dimension, we show that $\mathbb{A}^1$-contractibility is a fiberwise property: such a morphism is $\mathbb{A}^1$-contractible if and only if all its geometric fibers are $\mathbb{A}^1$-contractible. We apply this criterion to $\mathbb{A}^n$-fiber spaces, obtaining a geometric description of their $\mathbb{A}^1$-contractibility in terms of local factorizations as towers of torsors under vector bundles, building on results of Asanuma. In low relative dimensions, we establish rigidity results. In relative dimension $1$, $\mathbb{A}^1$-contractible morphisms over normal bases are precisely Zariski locally trivial $\mathbb{A}^1$-bundles. In relative dimension $2$, we show that over bases with characteristic zero residue fields, $\mathbb{A}^1$-contractible morphisms are $\mathbb{A}^2$-fiber spaces, and we obtain Zariski local triviality under additional hypotheses on the base. We also exhibit counterexamples in positive and mixed characteristic and formulate open problems concerning the existence of exotic $\mathbb{A}^1$-contractible surfaces.

2605.07636 2026-05-11 math.CV

Meromorphic functions and linearization phenomena in partial differential equations

Sujoy Majumder, Debabrata Pramanik, Jhilik Banerjee

AI总结 本文研究了涉及微分和函数算子的多复变数非线性偏微分方程的亚纯解。通过分析特定形式的方程,作者探讨了亚纯函数与整函数在复合运算下的线性化现象,并拓展了此前关于函数微分方程亚纯解的研究至多复变数情形,揭示了值分布性质对非线性函数方程所施加的刚性约束。

Comments 14

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英文摘要

In this paper, we investigate meromorphic solutions of certain nonlinear partial differential equations in several complex variables involving differential and functional operators. Let $f$ be a non-constant meromorphic function in $\mathbb{C}$, $g$ an entire function in $\mathbb{C}^n$, and $h(z)=f(z_1+z_2+\ldots+z_n)$. We study the equations \begin{align*} \frac{\partial h(z)}{\partial z_i}=a G^g_{h}(z)+bh(z)+c\;\;\text{and}\;\;\frac{\partial h(z)}{\partial z_i}=a(z)G^g_{h}(z)+b(z)h(z)+c(z), \end{align*} where $z\in\mathbb{C}^n$, $i\in\{1,2,\ldots,n\}$, $a(\neq 0), b, c\in\mathbb{C}$ or $a(z)(\not\equiv 0), b(z),c(z)$ are polynomials in $\mathbb{C}^n$, and $G^g_h(z)=h(g(z),g(z),\ldots,g(z))$. The results obtained in the paper, extend previous studies on meromorphic solutions of functional-differential equations to the setting of several complex variables, and further illustrate the rigidity imposed by value distribution properties on nonlinear functional equations.

2605.07629 2026-05-11 math.DG math.AP math.SP

Strichartz and Spectral Projection Estimates on Asymptotically Conic Manifolds

Zhexing Zhang

AI总结 本文研究了渐近锥形流形上的Strichartz估计与谱投影估计问题。作者在假设其捕获集足够邻域具有负曲率的条件下,证明了无损失的单位区间Strichartz定理以及具有欧几里得端的非正曲率流形上的谱投影定理。此外,还讨论了高维渐近欧几里得流形上的谱投影估计,并假设了一些局部平滑估计。

Comments arXiv admin note: text overlap with arXiv:2504.07238

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英文摘要

We prove the lossless unit interval Strichartz theorem on asymptotically conic surfaces, assuming that a large enough neighborhood of its trapped set has negative curvature. We also prove the spectral projection theorem on surfaces with Euclidean ends and nonpositive curvature, assuming a large enough neighborhood of its trapped set has negative curvature. We also discuss the spectral projection theorem on asymptotically Euclidean manifolds with dimension greater than or equal to 3, assuming some local smoothing estimates.

2605.07627 2026-05-11 quant-ph math.OC physics.atom-ph physics.comp-ph

A Unified Local Light-shifts Encoding For Solving Optimization Problems on a Rydberg Annealer

Kapil Goswami, Peter Schmelcher

AI总结 该论文提出了一种统一的本地光频移编码方法,用于在里德伯量子退火器上求解组合优化问题。通过将多种问题(如二元SAT、集合打包、蛋白质折叠等)映射到二次无约束二元优化(QUBO)形式,并利用里德伯原子的长程相互作用和可调本地失谐特性,实现了高效的量子退火求解。研究还引入了一种通用的难度参数,用于量化不同问题的优化景观复杂度,提升了框架的适用性和问题分析能力。

Comments 26 pages, 6 figures, 1 table

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英文摘要

Combinatorial optimization problems play a central role in computer science with many real world applications. A number of relevant problems remain computationally difficult to solve as they lie in the NP-hard complexity class. We present a unified framework for solving such optimization problems represented in the quadratic unconstrained binary optimization (QUBO) formalism, namely two-SAT, XOR-SAT, mixed-two-XOR-SAT, set packing, quadratic assignment, binary clustering, and protein folding, by expanding the domain of applications of \textit{PRR, 6(2), 023031}. A direct mapping from the QUBO form of these problems onto the Rydberg quantum platform is demonstrated as our first step. This mapping to the Rydberg system depends on distance-dependent long-range interactions and configurable local detuning, thus reducing resource overhead and improving scalability. Following-up on the encoding, the solution is reached by steering the system toward the ground state of the target Hamiltonian using an optimized quantum annealing protocol that controls the time-dependent detuning and Rabi frequency profiles. The framework can handle a variety of problems, each with different complexity. To quantify the complexity of any problem, a generalized hardness parameter is introduced that compares different problems based on the structure of their optimization landscapes. This is a proceedings contribution to the Athens Workshop in Theoretical Physics: 10th Anniversary, held at the National and Kapodistrian University of Athens on December 17-19 2025.

2605.07626 2026-05-11 math.NT

Weighted Distributions of Complex Multiplication Orders in Ordinary Isogeny Classes

Mohammed el baraka ans Siham ezzouak

AI总结 本文研究有限域上普通椭圆曲线同源类中复乘环的分布问题,提出了一种全局算术框架。通过引入加权类数,作者得到了整个同源类中复乘环的精确分布公式,并引入了加权精确分布和累积分布的概念,拓展了传统的局部观点。研究还揭示了复乘曲线的存在性与类域论之间的联系,并给出了具有指定复乘环的素数的自然密度,为同源图几何与类域论的结合提供了统一的理论基础。

Comments 11 pages

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英文摘要

We develop a global arithmetic framework for studying endomorphism rings inside ordinary elliptic isogeny classes over finite fields. Let p be a prime and let I(t,p) be an ordinary isogeny class over the finite field F_p with Frobenius trace t. The discriminant Delta = t^2 - 4p can be written as Delta = v^2 D_K, where D_K is the fundamental discriminant of an imaginary quadratic field K. In this setting, the possible endomorphism rings are precisely the quadratic orders O_f = Z + f O_K, with f dividing v. Building on Deuring's correspondence, we express the distribution of these orders in terms of weighted class numbers h*(D) = h(D)/w(D), and obtain explicit formulas for global distributions across the entire isogeny class. This approach goes beyond the classical local viewpoint, where the endomorphism ring is constant along each level of an ell-isogeny volcano. In particular, we introduce weighted exact and cumulative distributions of endomorphism rings. These distributions induce canonical laws for the ell-adic valuation of conductors and recover the vertical stratification of ell-volcanoes in an averaged sense. On the global side, by varying the prime p, we relate the existence of curves with a prescribed CM order O_D to splitting conditions in the associated ring class field L_D. Using the Chebotarev density theorem, we obtain the natural density 1/(2h(D)) for primes admitting CM by O_D. This gives a horizontal distribution law complementary to the vertical conductor distribution. These results establish a unified perspective linking Deuring theory, isogeny graph geometry, and class field theory. They also provide a natural framework for quantitative and algorithmic studies of ordinary isogeny classes.

2605.07625 2026-05-11 math.ST stat.ML stat.TH

Statistical Convergence of Spherical First Hitting Diffusion Models

Simon Bienewald, Lukas Trottner

AI总结 本文研究了球面支持的 Sobolev 光滑数据分布下,首次击中扩散模型(FHDM)在总变分意义下的统计收敛性质。该模型是一种具有随机生成时间的去噪扩散模型,能够高效生成定义在已知流形上的数据。作者证明了 FHDM 在对数因子范围内达到了最小最大最优收敛率,这是首次针对具有随机生成时间的去噪扩散模型的统计最优性结果。

详情
英文摘要

Denoising diffusion models have evolved into a state-of-the-art method for tasks in various fields, such as denoising and generation of images, text generation, or generation of synthetic data for training of other machine learning models. First hitting diffusion models (FHDM) are a particular class of denoising diffusion models with \textit{random} adaptive generation time tailored to generate data on a known manifold. Building on the conditioning framework of Doob's $h$-transform these models leverage the given information on the target data manifold to demonstrate strong performance across tasks while offering distinct features such as time-homogeneous dynamics of the generating process and a reduced average simulation time. Even though the theoretical investigation of standard forward-backward diffusion models has attracted much attention in the recent past, the statistical convergence properties of FHDMs are not yet understood. In this work, we show that, up to logarithmic factors, FHDMs achieve the minimax optimal convergence rate in total variation for spherically supported Sobolev smooth data distributions. In particular, this is the first statistical optimality result for denoising diffusion modelling with random generation time.