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2606.14244 2026-06-15 astro-ph.HE 新提交

Exploring the nature of Galactic unassociated sources detected by the Fermi-LAT

探索Fermi-LAT探测到的银河系未关联源的性质

F. Acero, A. Acharyya, A. Adelfio, M. Ajello, E. Aviano, L. Baldini, J. Ballet, C. Bartolini, D. Bastieri, J. Becerra Gonzalez, R. Bellazzini, A. Bhat, E. Bissaldi, R. Bonino, P. Bruel, R. A. Cameron, P. A. Caraveo, F. Casaburo, F. Casini, E. Cavazzuti, N. Cibrario, S. Ciprini, G. Cozzolongo, P. Cristarella Orestano, F. Cuna, S. Cutini, F. D'Ammando, P. de la Torre Luque, D. Depalo, N. Di Lalla, A. Dinesh, L. Di Venere, A. Dominguez, J. Eagle, C. Fernandez-Suarez, A. Fiori, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, C. Gasbarra, D. Gasparrini, S. Germani, F. Giacchino, N. Giglietto, M. Giliberti, F. Giordano, M. Giroletti, I. A. Grenier, M.-H. Grondin, S. Guiriec, R. Gupta, M. Hashizume, E. Hays, J.W. Hewitt, A. Holzmann Airasca, D. Horan, X. Hou, T. Kayanoki, M. Kerr, M. Kuss, D.A. Langis, A. Laviron, M. Lemoine-Goumard, A. Liguori, J. Li, I. Liodakis, P. Loizzo, F. Longo, F. Loparco, S. Lopez Pérez, L. Lorusso, B. Lott, M. N. Lovellette, P. Lubrano, S. Maldera, D. Malyshev, G. Marti-Devesa, R. Martinelli, M. N. Mazziotta, I.Mereu, M. Michailidis, P. F. Michelson, T. Mizuno, P. Monti-Guarnieri, M. E. Monzani, A. Morselli, M. Negro, N. Omodei, M. Orienti, E. Orlando, D. Paneque, G. Panzarini, M. Persic, M. Pesce-Rollins, R. Pillera, T. A. Porter, G. Principe, S. Raino, R. Rando

AI总结 利用机器学习分类和蒙特卡洛模拟,研究Fermi-LAT在银道面附近探测到的未关联源,发现其具有陡峭弯曲谱和特殊纬度分布,可能源于弥散发射的误建模或新类型伽马射线源。

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Comments
Accepted for publication in the Astrophysical Journal Supplement. Data posted at this https URL (https://zenodo.org/records/20342245)
AI中文摘要

我们研究了Fermi-LAT在银道面附近(|b|<10°)探测到的未关联源的性质,这些源占4FGL-DR4星表中所有源的16%。这些源(称为软银河未关联源,SGUs)表现出已知伽马射线源类别中未发现的性质,这一点通过机器学习分类方法得到证实。具体而言,这些性质包括在1 GeV以下达到峰值的陡峭弯曲谱,以及具有窄分量和宽分量(分别称为尖峰和肩峰)的特定银纬分布。我们突出显示了一些源团。探索了新的可能源类别,但只有恒星形成区被发现占未关联源群体的显著比例(最多10%)。对175个最亮源对应体的彻底搜索发现了一些可能的对应体,但未揭示整个群体的性质线索。我们研究了SGUs起源于弥散发射误建模团块的可能性。使用蒙特卡洛模拟,在关于团块空间延伸的特定条件下,可以重现SGU谱。利用13CO MOPRA数据探索了SGUs与12CO示踪剂未计及的气体之间的可能联系,但结果不明确。SGUs起源于弥散发射的可能性仍然存在。然而,SGUs代表一类新的伽马射线源的场景也不能完全排除。

英文摘要

We investigate the nature of the unassociated sources detected by the Fermi-LAT close (|b|<10°) to the Galactic plane, representing 16% of all sources in the 4FGL-DR4 catalog. The bulk of these sources (referred to as soft Galactic unassociated sources, SGUs) exhibit properties not found in known classes of gamma-ray emitters, as confirmed by a machine-learning classification approach. In particular, these properties include a steep, curved spectrum peaking below 1 GeV and a specific Galactic-latitude distribution with both a narrow and a broad component (dubbed the spike and the shoulder, respectively). Some source clusters are highlighted. New plausible source classes are explored, but only star-forming regions are found to account for a significant fraction (at most 10%) of the unassociated population. A thorough search for counterparts to the 175 brightest sources brings out a number of plausible counterparts but does not reveal clues about the nature of the whole population. We investigate the possibility that SGUs originate from mismodeled clumps of diffuse emission. Using Monte Carlo simulations, the SGU spectra can be reproduced in this scenario under an ad hoc condition concerning the clump spatial extension. The possible connection between the SGUs and gas not accounted for by the 12CO tracer is explored using the 13CO MOPRA data but leads to inconclusive results. The origin of SGUs being related to diffuse emission remains plausible. However, a scenario whereby SGUs represent a new class of gamma-ray emitters cannot be fully excluded.

2606.14242 2026-06-15 physics.plasm-ph 新提交

Free-Molecular Face-Flux Preprocessing for Reduced Neutral-Continuity Modeling in Hall Thrusters: Particle-Based Reference and Deterministic SN-DFEM Realization

霍尔推进器中用于简化中性连续建模的自由分子面通量预处理:基于粒子的参考与确定性SN-DFEM实现

Yingjie Chen, Xi Chen, Yinjian Zhao

AI总结 针对霍尔推进器中中性气体输运的高计算成本问题,提出自由分子预处理策略,通过粒子参考和确定性SN-DFEM方法提供面通量闭合,显著降低统计误差。

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AI中文摘要

中性气体输运直接影响霍尔推进器中的电离源、推进剂利用率和低频放电振荡。高保真度的基于粒子的中性模型或DSMC方法可以描述稀薄气体输运,但计算成本高;相比之下,简化的中性连续模型更便宜,但需要对中性速度或面法向通量进行闭合。在低压无碰撞近似下,本文采用自由分子预处理策略,以与底层输运一致的方式提供参考密度场以及简化中性连续方程所用的平均速度或面法向通量闭合。在此基础上,基于粒子的自由分子面通量预处理器作为随机参考,并提出了SN-DFEM确定性自由分子预处理器,在统一的自由分子输运框架内生成相应的参考密度、速度矩和面法向通量。结果表明,在基线连续性恢复测试中,SN-DFEM预处理器保留了主要的中性密度和速度结构,并将面通量闭合的统计误差降低了约三个数量级。一个预设的中等电离损失案例进一步展示了该框架在具有体积中性移除的自由分子预处理中的扩展性。

英文摘要

Neutral gas transport directly affects the ionization source, propellant utilization, and low-frequency discharge oscillations in Hall thrusters. High-fidelity particle-based neutral models or DSMC methods can describe rarefied gas transport, but they are computationally expensive; in contrast, reduced neutral-continuity models are cheaper but require a closure for the neutral velocity or face-normal flux. Under a low-pressure collisionless approximation, this work adopts a free-molecular preprocessing strategy to provide a reference density field and the mean-velocity or face-normal-flux closure used by the reduced neutral-continuity equation in a manner consistent with the underlying transport this http URL this basis, a particle-based free-molecular faceflux preprocessor is used as a stochastic reference, and an SN-DFEM deterministic free-molecular preprocessor is proposed to generate the corresponding reference density, velocity moments, and face-normal fluxes within a unified free-molecular transport framework. Results show that the SN-DFEM preprocessor preserves the main neutral-density and velocity structures and reduces the statistical error in face-flux closure by about three orders of magnitude in the baseline continuity-recovery test. A prescribed moderate ionization-loss case further demonstrates the extension of the framework to free-molecular preprocessing with volumetric neutral removal.

2606.14241 2026-06-15 math.CO math.CA 新提交

An explicit formula for Koornwinder moments and Rains' positivity conjecture

Koornwinder矩的显式公式与Rains正性猜想

Younggwang Cho, Donghyun Kim, Jang Soo Kim, Hojoon Lee, Jing Liu, Minho Song

AI总结 本文推导了Koornwinder矩的显式公式,精确表述了Rains关于其最小分子正性的猜想,并在特殊参数下证明了推广猜想,通过非相交格路和演讲厅表给出了组合解释。

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33 pages, 4 figures
AI中文摘要

非对称简单排斥过程(ASEP)是一个重要的粒子模型,与正交多项式有深刻联系。受此启发,Corteel和Williams在$t=q$时引入了Koornwinder矩$M^{Z}_{\lambda}$,它推广了Askey-Wilson多项式的矩。他们证明了双物种ASEP的配分函数等于单行划分$\lambda$的$M^{Z}_{\lambda}$。本文研究了Rains关于Koornwinder矩$M^{Z}_{\lambda}$的最小分子正性的猜想。我们推导了该矩的第一个显式公式,从而通过确定$M^{Z}_{\lambda}$的最小分母得到了猜想的精确表述。我们还提出了一个关于更一般的由两个划分索引的Koornwinder矩$M^{Z}_{\lambda,\mu}$在特殊参数值下的推广猜想。我们在两个特殊情形下证明了推广的Rains猜想:$(\xi,q)=(1,0)$和$(\xi,q)=(1,1)$。对于$(\xi,q)=(1,0)$,我们构造了一个格路模型,并得到了$M^{Z}_{\lambda,\mu}$关于非相交格路的组合公式。对于$(\xi,q)=(1,1)$,我们建立了$M^{Z}_{\lambda,\mu}$的显式乘积公式,并利用演讲厅表给出了组合解释。

英文摘要

The asymmetric simple exclusion process (ASEP) is an important particle model with deep connections to orthogonal polynomials. Motivated by this connection, Corteel and Williams introduced the Koornwinder moments $M^{Z}_{\lambda}$ at $ t=q $, which generalize the moments of Askey--Wilson polynomials. They showed that the partition function of the two-species ASEP is equal to $M^{Z}_{\lambda}$ for a one-row partition $ \lambda $. In this paper, we investigate a conjecture of Rains on the positivity of the minimal numerator of the Koornwinder moment $M^{Z}_{\lambda}$. We derive the first explicit formula for this moment, thereby obtaining a precise formulation of the conjecture by determining the minimal denominator of $M^{Z}_{\lambda}$. We also propose a generalization of the conjecture for the more general Koornwinder moments $M^{Z}_{\lambda,\mu}$ indexed by two partitions at special parameter values. We prove the generalized Rains' conjecture in two special cases: $(\xi,q)=(1,0)$ and $(\xi,q)=(1,1)$. For $(\xi,q)=(1,0)$, we construct a lattice path model and obtain a combinatorial formula for $M^{Z}_{\lambda,\mu}$ in terms of non-intersecting lattice paths. For $(\xi,q)=(1,1)$, we establish an explicit product formula for $M^{Z}_{\lambda,\mu}$ and give a combinatorial interpretation using lecture hall tableaux.

2606.14236 2026-06-15 math.AG 新提交

Fano manifolds with complete intersection type VMRT

具有完全交型VMRT的Fano流形

Cenhao Li

AI总结 研究Picard数为一且VMRT为光滑线性非退化完全交的Fano流形,在附加条件下证明其双正则于标准超二次曲面。

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Comments
14 pages
AI中文摘要

我们研究Picard数为一且具有局部平坦VMRT结构的Fano流形,其一般点处的VMRT是光滑线性非退化完全交。我们证明,在满足两个附加假设之一时,这样的流形双正则于标准超二次曲面。证明使用了向量群$\mathbb C^n$的等变紧化、Euler对称射影簇、基本形式和特殊双有理变换。

英文摘要

We study Fano manifolds of Picard number one equipped with a locally flat VMRT structure whose VMRT at a general point is a smooth linearly non-degenerate complete intersection. We prove that such a manifold is biregular to the standard hyperquadric provided that one of two additional assumptions is satisfied. The proof uses equivariant compactifications of the vector group $\mathbb C^n$, Euler-symmetric projective varieties, fundamental forms, and special birational transformations.

2606.14234 2026-06-15 math.AG 新提交

Automorphism groups of non-normal affine toric surfaces

非正规仿射环面曲面的自同构群

Kirill Selin

AI总结 研究非正规仿射环面曲面的自同构群,发现当奇异轨迹含一维环面轨道时性质成立,否则可能不成立,并构造反例。

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15 pages, 4 figures
AI中文摘要

我们研究了非正规仿射环面曲面的自同构群。对于正规环面曲面,自同构群的连通分支总是由作用环面和根子群生成,但我们证明这对于非正规曲面一般不成立。具体地,我们证明当奇异轨迹包含一维环面轨道时该性质成立,但当奇异轨迹为孤立点时可能不成立。为说明这一点,我们在 $\mathbb{A}^4$ 中构造了一个显式的非正规仿射环面曲面,其恒等连通分支严格大于由该曲面的环面和根自同构生成的子群。

英文摘要

We investigate the automorphism groups of non-normal affine toric surfaces. While the connected component of the automorphism group of a normal toric surface is always generated by the acting torus and root subgroups, we prove that this fails for non-normal surfaces in general. Specifically, we show that the property holds if the singular locus contains a one-dimensional torus orbit, but can fail if the singular locus is an isolated point. To illustrate this, we construct an explicit non-normal affine toric surface in $\mathbb{A}^4$ whose connected component of the identity is strictly larger than the subgroup generated by the torus and root automorphisms of the surface.

2606.14233 2026-06-15 cs.SE cs.CR 新提交

Evaluating LLMs for Obfuscation Detection and Classification in Android Apps

评估LLMs在Android应用中的混淆检测与分类能力

Luca Ferrari, Marco Alecci, Jordan Samhi, Tegawende' F. Bissyande', Jacques Klein, Mariano Ceccato, Luca Verderame

AI总结 本研究通过大规模实验评估大型语言模型(LLMs)在无需手工规则或训练的情况下,通过语义推理检测Android应用中的代码混淆,并与现有SAST方法对比。

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AI中文摘要

Android应用程序(app)开发者越来越依赖代码混淆技术来阻碍逆向工程和保护知识产权。然而,混淆也降低了静态分析和漏洞检测工具的有效性,给Android安全分析带来了挑战。现有的Android应用混淆检测方法主要依赖手工启发式规则、工程化特征或特定任务的学习流程,这些方法可能难以泛化到不断演变的混淆策略。本文提出了一项大规模实证研究,调查大型语言模型(LLMs)通过语义推理检测Android应用中混淆的能力。我们的研究评估了现成的LLMs是否能够在没有手工规则、预定义签名或专用模型训练的情况下识别混淆代码。实证评估在包含使用多种技术混淆的app的受控基准数据集和从Google Play收集的真实世界Android应用数据集上进行。研究进一步考察了提示设计、模型选择和决策阈值对多个开源和专有LLMs的影响。最后,分析将基于LLM的推理与现有的基于SAST的混淆检测方法进行比较,并讨论了将LLMs应用于Android安全分析的更广泛意义和局限性。

英文摘要

Android applications (apps) developers increasingly rely on code obfuscation techniques to hinder reverse engineering and protect intellectual property. However, obfuscation also reduces the effectiveness of static analysis and vulnerability detection tools, creating challenges for Android security analysis. Existing approaches for detecting obfuscation in Android apps predominantly rely on handcrafted heuristics, engineered features, or task-specific learning pipelines, which may struggle to generalize across evolving obfuscation strategies. This paper presents a large-scale empirical study investigating the capability of Large Language Models (LLMs) to detect obfuscation in Android apps through semantic reasoning. Our study evaluates whether off-the-shelf LLMs can identify obfuscated code without relying on handcrafted rules, predefined signatures, or dedicated model training. The empirical evaluation is conducted on both a controlled benchmark containing an app obfuscated with multiple techniques and a real-world dataset of Android apps collected from Google Play. The study further examines the impact of prompt design, model selection, and decision thresholds across several open-weight and proprietary LLMs. Finally, the analysis compares LLM-based reasoning with existing SAST-based obfuscation-detection approaches and discusses the broader implications and limitations of applying LLMs to Android security analysis.

2606.14232 2026-06-15 astro-ph.SR 新提交

Magnetically Structured Oscillatory Power Along an Active-Region Transect in Near-UV Sunrise-III/SUSI Spectroscopy

沿活动区横断面的近紫外Sunrise-III/SUSI光谱中的磁结构振荡功率

Shahin Jafarzadeh, David B. Jess, Marco Stangalini, Peter H. Keys, Samuel D. T. Grant, Timothy J. Duckenfield, Glen Chambers, Sami K. Solanki, H. N. Smitha, Andreas Lagg, Achim Gandorfer, Alex Feller, Francisco A. Iglesias, Tino L. Riethmüller, Bianca Grauf, Johannes Hoelken, Yukio Katsukawa, Pietro Bernasconi, Thomas Berkefeld, Alberto Álvarez-Herrero, Masahito Kubo, David Orozco Suárez, Michael Carpenter, Alexander Bell, Valentín Martínez Pillet, Francisco Javier Bailén, Julian Blanco Rodríguez, Juan Sebastián Castellanos Durán, Edvarda Harnes, Ryohtaroh T. Ishikawa, Yusuke Kawabata, Takuma Matsumoto, Takayoshi Oba, Azaymi L. Siu-Tapia, Hanna Strecker, Dušan Vukadinović

AI总结 利用Sunrise-III/SUSI近紫外光谱,研究活动区不同磁环境中振荡功率的分布,发现功率在弱场区增强、强场区抑制,且存在谱线依赖性。

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Comments
Accepted for publication in The Astrophysical Journal Letters
AI中文摘要

我们利用来自Sunrise-III紫外光谱偏振成像仪(SUSI)的无大气影响、平流层近紫外光谱,对活动区不同磁环境中振荡功率的组织方式进行了多谱线表征。在富含谱线的327-329 nm窗口进行的短光栅扫描的两小时时间序列,沿一条包含以下区域的单一横断面采样:弱磁场环境、谱斑、太阳黑子和暗孔。从30条选定的相对未混合的吸收线中,我们提取了线心多普勒速度时间序列,并计算了Morlet小波细化全局光谱,从中形成了三个频段(2-4、4-6和6-12 mHz)的波段积分功率图。叠加的线分辨图揭示了清晰的依赖于环境的功率重新分布:2-4 mHz功率在弱场/谱斑段最强,但在本影和暗孔核中通常被抑制,而4-6 mHz和6-12 mHz功率在最强场区域相对增强,在半影和谱斑中表现出线依赖行为。在整个谱线集合中,这种宽频率结构是连贯的,但详细的空间分布和相对波段排名并非逐线相同——即使在有效形成深度相当的光谱线之间也是如此——表明清晰的谱线依赖性。这一新颖的结果意味着,单线测量可能遗漏局部波谱的次要成分,因为不同的谱线对共存扰动和模式的权重不同;因此,SUSI近紫外窗口提供了独特的诊断丰富的振荡映射,提供了传统单线或双线方法难以获得的优势。

英文摘要

We present a multi-line characterisation of how oscillatory power is organised across distinct magnetic environments in an active region using seeing-free, stratospheric near-ultraviolet spectroscopy from the Sunrise-III UV Spectropolarimeter and Imager (SUSI). A two-hour time series of short raster scans in the line-rich 327-329 nm window samples along a single transect that contains the following regions: weak magnetic-field surroundings, a plage, a sunspot, and a pore. From a set of 30 selected, relatively unblended absorption lines, we extract line-core Doppler-velocity time series and compute Morlet-wavelet refined global spectra from which we form band-integrated power maps for three frequency bands (2-4, 4-6, and 6-12 mHz). The stacked, line-resolved maps reveal a clear environment-dependent redistribution of power: 2-4 mHz power is strongest in the weak-field/plage segments but is commonly suppressed in the umbra and pore cores, while 4-6 mHz and 6-12 mHz power becomes relatively enhanced in the strongest-field regions, with line-dependent behaviour in the penumbra and plage. Across the line ensemble, this broad frequency structuring is coherent, but the detailed spatial distribution and relative band ranking are not identical from line to line - even among spectral lines with comparable effective formation depths - demonstrating clear line dependence. This novel result implies that single-line measurements may miss secondary components of the local wave spectrum because different lines weight co-existing perturbations and modes differently; therefore, the SUSI near-UV window provides a uniquely diagnostic-rich mapping of oscillations, offering leverage that is difficult to obtain with traditional one- or two-line approaches.

2606.14231 2026-06-15 cond-mat.quant-gas quant-ph 新提交

Spin mixing induced dynamics of spinor solitons in $F=1$ Bose Einstein condensates

$F=1$ 玻色-爱因斯坦凝聚体中自旋混合诱导的自旋孤子动力学

T. Panagos, A. Romero-Ros, G.C. Katsimiga, P. Schmelcher, P.G. Kevrekidis

AI总结 研究磁场下自旋$F=1$ BEC中暗-亮-暗和亮-暗-亮孤子相互作用,发现自旋相互作用导致束缚态破裂,并建立有效经典模型描述孤子动力学。

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AI中文摘要

我们探索了在磁场存在下均匀自旋$F=1$玻色-爱因斯坦凝聚体(BEC)中的孤子相互作用,重点关注暗-亮-暗和亮-暗-亮构型。我们研究了这些相互作用如何依赖于亮孤子之间的相位差以及它们在动力学过程中的影响。我们的发现与先前的非自旋结果一致,即在自排斥原子BEC中,同相亮孤子相互排斥,而异相亮孤子对相互吸引。潜在的亮孤子吸引力,加上暗-暗孤子相互作用的短程排斥,可能导致束缚态。然而,我们发现这些束缚态在自旋相互作用存在时由于组分超精细态之间的粒子交换动力学而破裂。此外,我们使用拉格朗日方法开发了一个有效的经典模型来描述孤子动力学。通过将模型与数值模拟进行比较,测试了模型的准确性。我们的结果表明,所提出的模型捕捉了自旋相互作用存在下孤子行为的基本特征,并在大多数情况下提供了一致的孤子轨迹和种间粒子交换动力学。

英文摘要

We explore soliton interactions in a homogeneous spinor $F=1$ Bose Einstein Condensate (BEC) in the presence of a magnetic field, focusing on dark bright dark and bright dark bright configurations. We investigate how these interactions depend on the phase differences among bright solitons and their influence during the dynamics. Our findings align with prior non spinor results, i.e., repulsion among in phase bright solitons and attraction among out of phase pairs in self repulsive atomic BECs. The potential bright soliton attraction, added to the short range repulsion of dark dark soliton interactions, can lead to bound states. However, we find that these bound states break in the presence of spinor interactions due to the particle exchange dynamics between the hyperfine states of the components. Additonally, we develop an effective classical model to describe the soliton dynamics, using a Lagrangian approach. The accuracy of the model is tested by comparing it against numerical simulations. Our results suggest that the proposed model captures the essential features of soliton behavior in the presence of spin interactions, and provides congruent soliton trajectories and interspecies particle exchange dynamics in most of the cases.

2606.14229 2026-06-15 astro-ph.HE 新提交

Fortifying gravitational-wave population inference with normalizing flows

利用归一化流强化引力波种群推断

Christian Adamcewicz, Hugh McDougall, Paul D. Lasky, Eric Thrane

AI总结 针对引力波事件后验样本近似误差导致种群推断不可靠的问题,提出使用嵌套样本或归一化流提高事件表征精度,确保大量事件合并时推断的可靠性。

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Comments
20 pages, 10 figures
AI中文摘要

随着LIGO-Virgo-KAGRA合作组(LVK)引力波瞬变目录的增长,我们从双黑洞并合的种群属性中获得了丰富的信息。目录中的事件由描述每个事件天体物理参数的后验样本表示。种群研究结合这些样本来测量黑洞质量和自旋等天体物理参数的分布。然而,每个事件的后验样本表示只是近似的。我们证明,当合并约300个事件时,数值误差可能变得足够大,导致种群推断结果不可靠。我们考虑两种解决方案。短期内,我们表明可以使用嵌套样本(LVK分析已产生)更准确地描述种群研究中的每个事件。但这只能提供暂时的缓解,直到嵌套样本表示变得不充分。长期来看,我们建议用归一化流表示每个事件。每个归一化流可用于生成任意大量新的后验样本,以便以足够的精度表示每个事件。

英文摘要

As the LIGO-Virgo-KAGRA collaboration's (LVK's) gravitational-wave transient catalog grows, we are learning a wealth of information from the population properties of binary black hole mergers. Events in the catalog are represented with posterior samples describing the astrophysical parameters for each event. Population studies combine these samples to measure the distribution of astrophysical parameters such as black hole masses and spins. However, the posterior-sample representation of each event is only approximate. We demonstrate that when $\gtrsim 300$ events are combined, the numerical error can become large enough that the resulting population inference is unreliable. We consider two solutions. In the short term, we show that nested samples (already produced by LVK analyses) can be used to more accurately describe each event in population studies. But this will only grant a temporary reprieve until the nested-sample representation becomes inadequate. In the longer term, we propose to represent each event with a normalizing flow. Each normalizing flow can be used to generate an arbitrarily large number of new posterior samples in order to represent each event with sufficient accuracy.

2606.14228 2026-06-15 cs.NI cs.DC 新提交

Selective Field Transmission: Bandwidth Efficient Communication under Standardized Message Schemas

选择性字段传输:标准化消息模式下的带宽高效通信

David Philipp Klüner, David Murach, Stefan Kowalewski, Alexandru Kampmann

AI总结 提出选择性字段传输(SFT)机制,通过动态适配传输内容至接收方实际需求,在保持标准接口不变的同时显著降低带宽消耗,且无额外延迟开销。

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Comments
8 pages, 9 figures, IEEE ETFA
AI中文摘要

在本文中,我们介绍并评估了选择性字段传输(SFT),这是一种中间件机制,它将发布-订阅系统中的传输内容与静态定义的消息类型解耦。工业和机器人开发者常常面临两难:他们可以遵循既定的最佳实践并使用标准消息类型(例如在机器人操作系统2(ROS 2)和COVESA项目中),以受益于可重用和可互操作的接口;或者他们可以引入专有的、针对项目定制的消息类型,以满足接收方需求从而减少带宽。SFT通过动态调整传输的消息组件以适应每个接收方的实际需求,同时保持未修改的标准接口,解决了这一权衡。接收方声明或自动推导所需的消息组件,并将其传达给发布方。然后,发布方仅序列化并传输每个接收方所需的组件子集,且开发者干预最小。我们的评估表明,SFT在无每消息可测量延迟开销的情况下实现了显著的带宽降低,节省量与未使用字段的数量和大小成正比。

英文摘要

In this paper, we introduce and evaluate Selective Field Transmission (SFT), a middleware mechanism that decouples transmission content from statically defined message types in publish-subscribe systems. Industrial and robotics developers often face a dilemma: They can follow established best practices and use standard message types, such as in the Robot Operating System 2 (ROS 2) and COVESA projects, to benefit from reusable and interoperable interfaces, or they can introduce proprietary, project-specific message types tailored to receiver requirements to reduce bandwidth. SFT resolves this trade-off by dynamically adapting the transmitted message components to each receivers actual needs while preserving unmodified standard interfaces. Receivers declare or automatically derive the required message components, which are communicated to the publisher. The publisher then serializes and transmits only the required component subset per receiver with minimal developer intervention. Our evaluation shows that SFT achieves significant bandwidth reductions without measurable per-message latency overhead, with savings proportional to the number and size of unused fields.

2606.14227 2026-06-15 physics.flu-dyn physics.ao-ph 新提交

Impact of alignments between fluctuating and mean density gradients on the scale-dependent energetics of stably stratified turbulence

波动密度梯度与平均密度梯度之间的对准对稳定分层湍流尺度依赖能量学的影响

Soumak Bhattacharjee, Stephen M. de Bruyn Kops, Andrew D. Bragg

AI总结 通过直接数值模拟,研究了稳定分层湍流中波动与平均密度梯度对准对湍动能和可用势能跨尺度输运的影响,发现对准与浮力通量反转及能量通量减弱相关,且强对准区域多出现在稳定区。

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AI中文摘要

涡量与应变率张量之间的非平凡对准在速度梯度演化和各向同性湍流的能量级联中起着重要作用。本文探讨了波动密度梯度与平均密度梯度之间的对准如何影响稳定分层湍流中跨尺度的湍动能(TKE)和可用势能(APE)的机制。这一研究受到分析结果的启发,该结果证明了它们之间的联系,并通过对强分层状态下$Pr = 1, 7, 50$的统计稳态稳定分层湍流进行直接数值模拟(DNS)来开展。在展示了梯度场对准如何依赖于尺度和$Pr$之后,我们表明对准与小尺度浮力通量的反转密切相关,并且强对准和弱对准区域对应于水平TKE跨尺度通量变弱的区域。APE通量也是如此,除了在较大尺度上,强对准区域与逆尺度APE通量相关。TKE和APE耗散率以及混合系数也显示出对准的强烈依赖性,尤其是对于$Pr=1$。最后,我们探讨了局部对准与流动稳定性之间的联系,并发现了一个非平凡的关系,即强对准区域令人惊讶地最常出现在稳定区域。这表明对准对流动能量学的动力学意义不能通过局部对准与局部流动稳定性之间的简单联系来理解。

英文摘要

Non-trivial alignments between vorticity and the strain-rate tensor play an important role in the evolution of velocity gradients and the energy cascade in isotropic turbulence. Here we explore how alignments between the fluctuating and mean density gradients impact the mechanisms governing the turbulent kinetic energy (TKE) and available potential energy (APE) across scales in stably stratified turbulence. This is motivated by analytical results that demonstrate a connection between them, and is conducted using direct numerical simulations (DNS) of statistically stationary, stably stratified turbulence for $Pr = 1, 7, 50$ in the strongly stratified regime. After demonstrating how the gradient field alignments depend on scale and $Pr$, we show that the alignments are intimately connected to the reversal of the buoyancy flux at small-scales, and that regions of strong alignment and misalignment correspond to regions where the horizontal TKE inter-scale flux becomes weak. The same is also true of the APE flux, except that at larger scales, regions of strong alignment are associated with an upscale APE flux. The TKE and APE dissipation rates, and the mixing coefficient also show a strong dependence on the alignment, especially for $Pr=1$. Finally, we explore the connection between the local alignment and stability of the flow, and we find a non-trivial relationship, with regions of strong alignment surprisingly occurring most often in stable regions. This demonstrates that the dynamical significance of the alignments on the flow energetics cannot be understood through a simple connection between the local alignments and local stability of the flow.

2606.14226 2026-06-15 quant-ph 新提交

Efficient Simulation of Szegedy Quantum Walk Formulations and Algorithms

Szegedy量子游走公式与算法的高效模拟

Sergio A. Ortega, Daniel K. Park

AI总结 提出基于基本更新和反射算子的框架,高效模拟Szegedy量子游走及其相位估计算法,对稠密图复杂度最优O(N^2),稀疏图线性于边数。

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Comments
27 pages, 15 figures (including Supplementary Material)
AI中文摘要

量子游走为广泛应用的量子算法提供了通用框架。我们开发了Szegedy量子游走的高效经典模拟方法,避免了完整幺正演化算子的显式构造。与先前局限于特定游走公式的方法不同,我们的框架基于基本更新和反射算子构建,能够模拟更广泛的Szegedy游走公式。我们进一步将这些方法扩展到与游走耦合的基于相位估计的算法,包括适用于大型稀疏图的实现。所得方法对具有N个节点的稠密图实现了最优的$O(N^2)$复杂度。对于稀疏图,计算成本随边数线性增长,在许多情况下为$O(N)$。我们在Python包SQWLib中实现了该框架,并通过模拟代表性算法(包括量子模拟退火和图上量子搜索)展示了其能力。这些结果为纯分析处理之外的Szegedy游走算法数值研究提供了实用工具。

英文摘要

Quantum walks provide a versatile framework for quantum algorithms across a wide range of applications. We develop efficient classical simulation methods for Szegedy quantum walks that avoid explicit construction of the full unitary evolution operator. Unlike previous approaches restricted to a particular walk formulation, our framework is built from fundamental update and reflection operators, enabling the simulation of a broader class of Szegedy walk formulations. We further extend these methods to phase-estimation-based algorithms coupled to the walk, including implementations suitable for large sparse graphs. The resulting methods achieve optimal $O(N^2)$ complexity for dense graphs with $N$ nodes. For sparse graphs, the computational cost scales linearly with the number of edges, which is $O(N)$ in many cases. We implement the framework in the Python package SQWLib and illustrate its capabilities through simulations of representative algorithms, including quantum simulated annealing and quantum search on graphs. These results provide a practical tool for studying Szegedy-walk-based algorithms numerically beyond purely analytical treatments.

2606.14225 2026-06-15 cs.IT cs.GT 新提交

The Algebraic Limits of Polynomial Information Measures

多项式信息度量的代数极限

Yuqing Kong

AI总结 研究满足独立零点和数据处理不等式的多项式依赖性度量,证明在非对称情况下不存在非零多项式,在对称情况下次数至少为2n,并应用于多任务同伴预测。

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AI中文摘要

本文研究两个随机变量之间依赖性的\emph{多项式}度量的存在性:联合分布的多项式函数,满足 (i) 在独立时为零,且 (ii) 在任一变量的后处理下不会增加(数据处理不等式,DPI)。互信息满足这两个性质,但它是联合分布的超越函数,因此无法从有限样本中无偏估计。多项式替代方案允许精确的有限样本无偏估计,多项式次数控制所需样本量。主要结果是负面的:在变量字母表大小不同的非对称情形(\(|X| > |Y|\))中,不存在非零多项式同时满足较大字母表一侧的 DPI 和在独立时为零。在对称情形 \(|X| = |Y| = n\) 中,我们建立了一个结构性结果:每个这样的多项式都被 \((\det U)^2\) 整除,其中 \(U\) 表示 \(n \times n\) 联合分布矩阵。因此,任何非平凡候选多项式的次数至少为 \(2n\)。基于行列式的互信息达到了这个下界。这些代数结果直接影响了\emph{多任务同伴预测},这是一个机制设计问题,其中委托人激励观察相关信号但没有真实情况的代理人诚实报告。每个运行在 \(\ell\) 个独立任务上的此类机制产生一个次数至多为 \(\ell\) 的多项式依赖性度量,因此我们的多项式次数下界直接转化为任务数量的下界:在非对称情形中,较大字母表一侧根本不存在有限任务机制,而在对称情形中至少需要 \(\ell \geq 2n\) 个任务。

英文摘要

The paper studies the existence of \emph{polynomial} measures of dependence between two random variables: polynomial functions of the joint distribution that (i) vanish on independence and (ii) cannot increase under post-processing of either variable (the data processing inequality, DPI). Mutual information satisfies both properties but is transcendental in the joint distribution, making it impossible to estimate without bias from finitely many samples. A polynomial alternative would admit an exact finite-sample unbiased estimator, with the polynomial degree controlling the required sample size. The main result is negative: in the asymmetric setting where the variables have different alphabet sizes (\(|X| > |Y|\)), no nonzero polynomial can simultaneously satisfy DPI on the larger-alphabet side and vanish on independence. In the symmetric case \(|X| = |Y| = n\), we establish a structural result: every such polynomial is divisible by \((\det U)^2\), where \(U\) denotes the \(n \times n\) joint distribution matrix. Consequently, any nontrivial candidate must have degree at least \(2n\). The determinant-based mutual information attains this lower bound. These algebraic results have direct consequences for \emph{multi-task peer prediction}, a mechanism-design problem in which a principal incentivizes honest reports from agents who observe correlated signals but no ground truth. Every such mechanism running on \(\ell\) independent tasks gives rise to a polynomial measure of dependence of degree at most \(\ell\), so our lower bounds on polynomial degree translate directly into lower bounds on the number of tasks: in the asymmetric case no finite-task mechanism exists on the larger-alphabet side at all, while the symmetric case requires at least \(\ell \geq 2n\) tasks.

2606.14224 2026-06-15 physics.optics 新提交

Analysis of a compact interferometric imager

紧凑型干涉成像仪分析

Laurent M. Mugnier, Vincent Michau, Hiyam Debary, Frédéric Cassaing

AI总结 研究用光子集成电路实现紧凑干涉成像仪的概念,分析其信噪比并与单孔径望远镜比较,发现低中空间频率噪声传播不利。

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AI中文摘要

光子集成电路(PIC)的出现将允许用密集的小孔径阵列干涉组合替代光学望远镜的大孔径。来自孔径对的光可以通过PIC组合,以提取称为复可见度的干涉图特征,从而重建观测目标。在这种紧凑型干涉成像仪中,常规望远镜中用于成像的光学组件不再必要。特别地,这种概念对于重量和尺寸至关重要的太空任务具有相关性。在本报告中,我们研究这种仪器概念,重点关注信噪比考虑。我们回顾了视场和空间分辨率的设计基础,并表明光谱分辨率必须不小于视场与分辨率之比。然后,我们分析了该概念的信噪比,假设每个空间频率仅记录一次,并将信噪比与单孔径望远镜进行比较。我们在傅里叶空间中对相同记录光子数进行比较。我们表明,干涉成像仪的噪声传播与具有平坦调制传递函数(水平大致由小孔径直径与最大基线之比决定)的单孔径望远镜相同。我们得出结论,在低和中等空间频率下,噪声传播对干涉成像仪不利。

英文摘要

The advent of photonic integrated circuits (PICs) will allow the replacement of the large aperture of an optical telescope by a dense array of small apertures combined interferometically. The light coming from aperture pairs can be combined by a PIC in order to extract interferogram characteristics known as complex visibilities, from which the observed object can then be reconstructed. In such a compact interferometric imager, the optical components dedicated to image formation in a regular telescope are no longer necessary. In particular, such a concept is relevant for space missions where weight and size are critical. In this communication, we study such an instrument concept, focusing on signal-to-noise considerations. We recall the design basis for the field and the spatial resolution, and we show that the spectral resolution must be no less than the field to resolution ratio. Then, we analyze the signal-to-noise ratio of this concept, assuming that each spatial frequency is recorded only once, and compare the signal-to-noise ratio with that of a monolithic telescope. We perform the comparison in Fourier space for an identical number of recorded photons. We show that the noise propagation of the interferometric imager is identical to that of a monolithic telescope that would have a flat Modulation Transfer Function with a level roughly given by the ratio of the small apertures' diameter to the maximum baseline. We conclude that the noise propagation in low and medium spatial frequencies is unfavorable for the interferometric imager.

2606.14223 2026-06-15 eess.SP 新提交

Event-Level Sensing for Intelligent 6G ISAC

面向智能6G ISAC的事件级感知

Haotian Liu, Zhiqing Wei, Xingwang Li, Ruizhong Xu, Zhiyong Feng

AI总结 本文提出事件级感知概念,通过连续时间状态建模实现目标意图和行为语义的持续识别与预测,推动6G ISAC从物理参数估计向深层环境理解演进。

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Comments
10 pages, and 5 figures
AI中文摘要

任务关键型网络(如车联网和低空经济)的智能化演进要求第六代(6G)网络超越离散物理参数估计,迈向更深层的环境理解。然而,现有集成感知与通信(ISAC)研究主要关注目标级感知,提供物理世界的碎片化快照,缺乏解释意图的行为语义能力。这一局限性阻碍了此类网络的智能化演进,并阻止6G获得必要的感知基础以演变为“智能服务引擎”。为弥补这一差距,ISAC必须向事件级感知推进,该感知通过建模连续时间状态实现对目标意图和行为语义的持续识别与预测。本文全面概述了6G ISAC网络中的事件级感知。我们首先介绍其基本概念、感知类型和代表性场景。然后回顾了波形设计、目标状态估计与跟踪以及事件识别等关键使能技术。此外,聚焦车联网和低空经济场景,讨论了ISAC事件级感知的代表性应用以及事件级信息对下游操作功能的智能增强。最后,我们强调了进一步推动ISAC事件级感知向智能和主动6G网络发展的未来研究趋势和潜在方向。

英文摘要

The intelligent evolution of mission-critical networks, such as the Internet of vehicles (IoV) and the low-altitude economy (LAE), requires sixth-generation (6G) networks to move beyond discrete physical parameter estimation toward deeper environmental understanding. However, existing integrated sensing and communications (ISAC) studies mainly focus on target-level sensing, which provides fragmented snapshots of the physical world and lacks the behavioral semantic capability to interpret intent. This limitation hinders the intelligent evolution of such networks and prevents 6G from acquiring the essential sensing foundation to evolve into an "intelligent service engine". To bridge this gap, ISAC must advance toward event-level sensing, which models continuous-time states to enable persistent recognition and prediction of target intent and behavioral semantics. This article presents a comprehensive overview of event-level sensing in 6G ISAC networks. We first introduce its fundamental concepts, sensing types, and representative scenarios. We then review key enabling techniques across waveform design, target state estimation and tracking, and event recognition. Furthermore, focusing on IoV and LAE scenarios, we discuss representative applications of ISAC event-level sensing and the intelligent enhancement of downstream operational functions enabled by event-level information. Finally, we highlight future research trends and potential directions to further advance ISAC event-level sensing toward intelligent and proactive 6G networks.

2606.14221 2026-06-15 math.DG math.AP 新提交

Regularity for the Geodesic X-Ray Transform in Nonsmooth Geometry

非光滑几何中测地线X射线变换的正则性

Pieti Kirkkopelto, Miika Manu, Mikko Salo

AI总结 本文研究非光滑简单流形上测地线X射线变换的正则性,通过符号平滑和低正则伪微分算子映射性质,改进了$L^p$函数上变换的单射性结果。

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Comments
19 pages
AI中文摘要

本文给出了非光滑简单流形上测地线X射线变换的正则性结果。作为应用,我们改进了作用于$L^p$函数的测地线X射线变换的先前单射性结果。这些结果基于正规算子的符号平滑论证以及低正则符号伪微分算子的映射性质。

英文摘要

In this article we give regularity results for the geodesic X-ray transform on nonsmooth simple manifolds. As an application, we improve previous injectivity results for the geodesic X-ray transform acting on $L^p$ functions. The results are based on symbol smoothing arguments for the normal operator and mapping properties of pseudodifferential operators with low regularity symbols.

2606.14220 2026-06-15 math.OC 新提交

A New Primal-Dual Algorithm with Convex Combination and Extrapolation for Convex-Concave Saddle Point Problems with Nonlinear Coupling Term

一种结合凸组合和外推的原始-对偶算法用于带非线性耦合项的凸-凹鞍点问题

Jialong Li, Zexian Liu, Xiaokai Chang

AI总结 针对带非线性耦合项的凸-凹鞍点问题,提出一种结合凸组合和外推策略的原始-对偶算法PDAce,通过在线性化点处计算雅可比矩阵并将外推移至映射空间,消除非线性残差项,实现无需线搜索的全局收敛,收敛率为O(1/N),加速版本aPDAce在强凸条件下达到O(1/N^2)甚至线性收敛。

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AI中文摘要

带非线性耦合项的凸-凹鞍点问题在信号处理、机器学习、鲁棒优化和生成模型等领域有广泛应用。原始-对偶算法广泛用于凸-凹鞍点问题。然而,在处理凸-凹鞍点问题中的非线性耦合项时,原始-对偶算法通常遇到变量空间与映射空间之间的几何不匹配、梯度信息延迟以及对线搜索的强依赖,导致性能不稳定且收敛分析复杂。为解决这些问题,我们提出了一种新的原始-对偶算法,命名为PDAce,通过结合凸组合和外推策略。具体而言,在原始变量的更新中,我们构造一个凸组合点来替代当前迭代点,并计算非线性耦合项中向量函数在该凸组合点处的雅可比矩阵。此外,我们利用凸组合点的最新信息将对偶变量更新中的外推扩展到映射空间。核心创新在于在凸组合点处对非线性耦合项中的向量函数进行线性化,并将外推从变量空间转移到非线性映射空间。这种设计完全消除了非线性残差项,并允许在没有线搜索的情况下进行严格的收敛分析。在温和的凸性假设下,我们构造了一个新的李雅普诺夫势函数,证明PDAce全局收敛,遍历收敛率为$\mathcal{O}(1/N)$。此外,我们开发了PDAce的加速版本aPDAce,在原始函数强凸时达到$\mathcal{O}(1/N^2)$的收敛率,当原始和对偶函数均强凸时达到线性收敛。

英文摘要

Convex-concave saddle point problems with nonlinear coupling term have wide applications in signal processing, machine learning, robust optimization, and generative models, among others. Primal-dual algorithms are widely used for convex-concave saddle point problems. However, when handling nonlinear coupling term in convex-concave saddle point problems, primal-dual algorithms usually encounter geometric mismatches between variable and mapping spaces, delayed gradient information, and strong dependence on linesearch, resulting in less stable performance and complex convergence analysis. To address these issues, we propose a new primal-dual algorithm named PDAce by combining convex combination and extrapolation strategies. More specifically, in the update of the primal variable, we construct a convex combination point to replace the current iterative point and compute the Jacobian matrix of the vector function in the nonlinear coupling term at the convex combination point. Besides, we use the latest information of convex combination points to extend extrapolation to the mapping space in the update of the dual variable. The core innovations lie in performing linearization of the vector function in the nonlinear coupling term at convex combination points and shifting extrapolation from the variable space to the nonlinear mapping space. This design completely eliminates nonlinear residual terms and allows for rigorous convergence analysis without linesearch. Under mild convex assumptions, we construct a new Lyapunov potential function to prove that PDAce is globally convergent with an ergodic convergence rate of $\mathcal{O}(1/N)$. Moreover, we develop an accelerated version of PDAce, termed aPDAce, which achieves $\mathcal{O}(1/N^2)$ rate under strong convexity of the primal function, and linear convergence when both the primal and dual functions are strongly convex.

2606.14214 2026-06-15 cs.NI eess.SY 新提交

StreamRTPS: Increasing DDS Bandwidth Efficiency by Reducing Protocol Overhead

StreamRTPS:通过减少协议开销提高DDS带宽效率

David Philipp Klüner, Stefan Kowalewski, Alexandru Kampmann

AI总结 提出三种扩展RTPS协议的方法:流协商机制、负载聚合方案和预测性心跳抑制策略,分别减少头部开销、IP/UDP开销和控制流量,在保持兼容性下最高降低带宽消耗50.6%。

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8 pages, 8 figures
AI中文摘要

本文提出了三种对实时发布订阅线协议(RTPS,数据分发服务DDS的基础)的扩展,以提高带宽效率。首先,一种流协商机制在发现阶段交换静态头部信息,运行时用紧凑的2字节标识符替代完整的RTPS头部。其次,一种负载聚合方案将同一定位器的样本聚合到单个UDP数据包中,减少IP和UDP头部开销。第三,一种预测性心跳抑制策略通过省略周期性通信模式的心跳来减少控制流量,在检测到丢失或时序违规时回退。所有三种机制通过扩展DDS发现以在支持时激活这些特性,保持与RTPS的兼容性。实验结果表明,在尽力传输下,流头部相比传统RTPS将带宽消耗降低高达27.9%,在可靠传输下,心跳抑制在流头部基础上进一步降低22.7%,同时两种情况下均保持传输延迟。

英文摘要

In this paper, we propose three extensions to the Real-Time Publish Subscribe wire protocol, on which Data Distribution Service (DDS) is based, to improve bandwidth efficiency. First, a stream negotiation mechanism exchanges static header information during discovery, replacing the full RTPS header at runtime with a compact 2 B identifier. Second, a payload aggregation scheme aggregates samples for the same locator into single UDP packets, reducing IP and UDP header costs. Third, a predictive heartbeat suppression strategy reduces control traffic by omitting heartbeats for periodic communication patterns, falling back upon detected loss or timing violations. All three mechanisms preserve Real-Time Publish Subscribe(RTPS) compatibility by extending DDS discovery to activate these features when supported. Experimental results show that stream headers reduce bandwidth consumption by up to 27.9 % compared to conventional RTPS under best-effort transport, and that heartbeat suppression yields a further 22.7 % reduction on top of stream headers under reliable transport, while preserving transmission latency in both cases.

2606.14213 2026-06-15 cond-mat.mtrl-sci cond-mat.soft 新提交

Vapor-to-glass preparation of biaxially aligned organic semiconductors

双轴取向有机半导体的气相到玻璃态制备

Jianzhu Ju, Debaditya Chatterjee, Paul M. Voyles, Harald Bock, Mark D. Ediger

AI总结 通过物理气相沉积结合表面平衡和模板生长,在远低于清亮点和玻璃化转变温度下制备了具有面内择优取向的双轴取向有机玻璃,为气相沉积玻璃增加了结构控制新维度。

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Comments
23 pages, 4 figures, SI included
AI中文摘要

物理气相沉积(PVD)提供了一种制备高稳定性和各向异性有机玻璃的途径,这些玻璃可用于有机发光器件等多层结构。先前的研究表明,PVD可以制备具有单轴对称性的各向异性玻璃,而本文制备了双轴取向玻璃,其中分子取向具有优选的面内方向。通过表面平衡机制和对齐基底上的模板生长的集体效应,在低于清亮点$T_{LC-iso}$高达180 K(以及低于玻璃化转变温度$T_g$ 50 K)的沉积温度下,使用单组分盘状(菲并苝酯)和棒状(伊曲康唑)介晶实现了宏观双轴取向。双轴取向有机半导体的制备为气相沉积玻璃增加了结构控制的新维度,并可能实现偏振发射和面内电荷迁移率控制。

英文摘要

Physical vapor deposition (PVD) provides a route to prepare highly stable and anisotropic organic glasses that are utilized in multi-layer structures such as organic light-emitting devices. While previous work has demonstrated that anisotropic glasses with uniaxial symmetry can be prepared by PVD, here, we prepare biaxially aligned glasses in which molecular orientation has a preferred in-plane direction. With the collective effect of the surface equilibration mechanism and template growth on an aligned substrate, macroscopic biaxial alignment is achieved in depositions as much as 180 K below the clearing point $T_{LC-iso}$ (and 50 K below the glass transition temperature $T_g$ ) with single-component disk-like (phenanthroperylene ester) and rod-like (itraconazole) mesogens. The preparation of biaxially aligned organic semiconductors adds a new dimension of structural control for vapor-deposited glasses and may enable polarized emission and in-plane control of charge mobility.

2606.14212 2026-06-15 math.AT math.GT 新提交

Coarse Homotopy Theory and Shape Theory

粗同伦理论与形状理论

Felix Lange

AI总结 建立欧几里得锥的粗同伦理论与紧度量空间形状理论的联系,通过逆极限序列和强形状等价刻画粗同伦等价,并证明粗Whitehead定理及其反例。

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Comments
Doctoral Dissertation submitted to and accepted by the University of Greifswald
AI中文摘要

本论文建立了欧几里得锥的粗同伦理论与紧度量空间形状理论之间的联系。对于紧度量空间$X$,欧几里得锥$cX$的粗同伦群由$X$的点状形状不变量决定,并嵌入到一个涉及Čech同伦群的$\varprojlim^1$序列中。利用逆映射望远镜和强形状理论,我们证明两个紧度量空间是强形状等价的当且仅当它们的欧几里得锥是粗同伦等价的。我们还证明了欧几里得锥的粗Whitehead定理的一个版本。相比之下,我们推导出任意固有度量空间的类似$\varprojlim^1$序列,并构造了一个反例表明粗Whitehead定理在这种一般情形下不成立。

英文摘要

This thesis establishes a connection between the coarse homotopy theory of Euclidean cones and the shape theory of compact metric spaces. For a compact metric space $X$, the coarse homotopy groups of the Euclidean cone $cX$ are determined by pointed shape invariants of $X$, fitting into a $\varprojlim^1$ sequence involving the Čech homotopy groups. Using inverse mapping telescopes and strong shape theory, we prove that two compact metric spaces are strong shape equivalent if and only if their Euclidean cones are coarsely homotopy equivalent. We also prove a version of the coarse Whitehead theorem for Euclidean cones. In contrast, we derive a similar $\varprojlim^1$ sequence for arbitrary proper metric spaces, and construct a counterexample showing that the coarse Whitehead theorem fails in this general setting.

2606.14208 2026-06-15 hep-th cond-mat.mes-hall quant-ph 新提交

Real-time pseudo entropy and modular-Hamiltonian correlations

实时伪熵与模哈密顿量关联

Tatsuhiro Misumi

AI总结 研究初始纯态经酉时间演化后的实时伪熵,发现其短时行为由物理哈密顿量与模哈密顿量的关联决定,虚部反映时间导向的模响应。

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12 pages, 3 figures
AI中文摘要

伪熵是约化转移矩阵定义的纠缠熵的复值推广。我们研究初始纯态与其酉时间演化之间的实时转移矩阵相关的伪熵。对于子系统 $A$,我们证明实时伪熵的短时行为由物理哈密顿量 $H$ 与初始约化态的模哈密顿量 $K_A=-\log\rho_A$ 之间的关联主导:$ S_A(t,0)=S_A(0)-it \langle K_A(H-\langle H\rangle)\rangle + \mathcal{O}(t^2)$。对于厄米动力学,初始虚部响应由 $H$ 和 $K_A$ 的对称协方差控制(带整体负号),而初始实部响应由它们的对易子决定。因此,实时伪熵的虚部不仅仅是分支伪迹:它是微观时间演化与子系统粗粒化之间的关联产生的时间导向模响应。我们阐明了这一结果与已知的伪熵第一定律的关系,在Schmidt对角模型中推导了全阶表达式,将热伪熵作为特例恢复,在双量子比特模型中说明了协方差/对易子分解,并在横场伊辛链淬火中确认了协方差响应,包括伊辛临界区附近模磁化率的有限尺寸研究。我们讨论了这种振幅级导向响应如何与普通熵产生相关联,并给出了一个具体的 $\mathcal{PT}$ 对称玩具模型来说明非厄米扩展。

英文摘要

Pseudo entropy is a complex-valued generalization of entanglement entropy defined from a reduced transition matrix. We study the pseudo entropy associated with a real-time transition matrix between an initial pure state and its unitary time evolution. For a subsystem $A$, we show that the short-time behavior of real-time pseudo entropy is governed by the correlation between the physical Hamiltonian $H$ and the modular Hamiltonian $K_A=-\log\rho_A$ of the initial reduced state, $ S_A(t,0)=S_A(0)-it \langle K_A(H-\langle H\rangle)\rangle + \mathcal{O}(t^2)$. For Hermitian dynamics, the initial imaginary response is controlled by the symmetrized covariance of $H$ and $K_A$ with an overall minus sign, while the initial real response is governed by their commutator. Thus the imaginary part of real-time pseudo entropy is not merely a branch artifact: it is a time-oriented modular response generated by the correlation between microscopic time evolution and subsystem coarse graining. We clarify the relation of this result to the known first law of pseudo entropy, derive an all-order expression in a Schmidt-diagonal model, recover thermal pseudo entropy as a special case, illustrate the covariance/commutator decomposition in a two-qubit model, and confirm the covariance response in transverse-field Ising-chain quenches, including a finite-size study of a modular susceptibility near the Ising critical region. We discuss how this amplitude-level oriented response can be related to ordinary entropy production, and also give a concrete $\mathcal{PT}$-symmetric toy-model illustration of the non-Hermitian extension.

2606.14207 2026-06-15 physics.chem-ph 新提交

Fast and accurate simulation of Raman spectra of gold-organic systems

金-有机体系拉曼光谱的快速准确模拟

Auguste Tetenoire, Vijaya Raghavan Kannan, Mikaël Kepenekian, Arnaud Fihey

AI总结 本文评估了DFTB方法在不同尺度金-有机体系中模拟拉曼光谱的精度,通过与DFT和实验对比验证,并讨论了模型选择(团簇或周期性表面)对结果的影响。

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AI中文摘要

解析接枝在金属基底上的分子的拉曼光谱特征通常是一项困难的任务,量子化学方法可以提供宝贵的额外合理化和信号归属,特别是用于探测与基底形成的键。在基于Au-C键的金-有机架构的具体情况下,文献中可用的实验和理论参考数据有限,基于量子力学的拉曼模拟随着系统尺寸的增加很快变得不可承受。在这项工作中,我们评估了一种成本高效的DFTB方法在不同尺度(从金配合物到功能化金表面)模拟金-有机体系拉曼光谱的精度。通过将有机金属金(I)和(III)配合物的DFTB拉曼光谱与DFT和实验参考数据进行仔细比较来验证该方法后,我们讨论了接枝在金聚集体上的分子的情况。对于这些模拟,模型(团簇或周期性表面)的选择似乎至关重要,并且当考虑完整的金属板时(由于该方法计算成本低而成为可能),会出现显著差异(峰的位置和强度)。

英文摘要

Resolving the spectral Raman signature of molecules grafted on a metallic support is often a difficult task, in which quantum chemistry methods allow for precious additional rationalization and signal attributions, especially to probe the formation of a bond with the support. In the specific case of gold-organic architectures based on a Au-C bond, only a limited amount of experimental and theoretical reference data are available in the literature, and Raman simulations based on quantum mechanics quickly become unaffordable with the size of the system. In this work, we evaluate the precision of a cost-efficient DFTB method to simulate Raman spectra of gold-organic systems at different scales, from gold complexes to functionalized gold surfaces. After a validation of the method through a careful comparison of DFTB Raman spectra of organometallic gold(I) and (III) complexes to DFT and experimental reference data, we discuss the case of molecules grafted on gold aggregates. For these simulations, the choice of the model (cluster or periodic surface) appears to be critical, and significant differences arise (positions and intensities of the peaks) when considering a full metallic slab, as allowed by the low computational cost of the method.

2606.14206 2026-06-15 quant-ph 新提交

Fourier analysis of quantum neural network with non-linear data embedding

非线性数据嵌入的量子神经网络的傅里叶分析

Haiyue Kang, Martin Sevior, Muhammad Usman

AI总结 本文通过傅里叶分析研究振幅嵌入变分量子电路的表达能力与贫瘠高原,推导了傅里叶系数的均值和方差,并分析了噪声的影响。

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26 pages, 12 figures
AI中文摘要

傅里叶分析已成为理解变分量子电路(VQC)模型表达能力的关键工具,也是贫瘠高原(BP)的重要指标。现有文献仅研究了无噪声环境下的角度嵌入VQC,本文则发展了具有非线性数据嵌入的VQC的傅里叶分析,特别关注振幅嵌入,它提供了一种自然紧凑的编码方案。我们首先研究了振幅嵌入中输入特征域的一个细微差异,这导致零频率傅里叶系数具有独特的表达能力。通过假设参数空间生成的酉系综至少构成关于酉群的2-设计,我们利用Weingarten微积分推导出傅里叶系数的均值集中在零,而方差关于多维频率幅度呈指数衰减阶。当考虑具有酉Kraus算子和概率$\{p_k\}$的噪声信道时,方差进一步被因子$\left(\sum_k p_k^2\right)^{Q}<1$抑制,其中$Q$是应用的信道实例数。此外,我们通过无噪声和噪声模拟演示并验证了分析结果,包括目标函数被分解为非整数频率的情况,突显了该方法的实际效用。我们的结果为振幅编码VQC建立了严格的傅里叶框架,提供了表达能力的理论保证,从而在频域中实现可训练性缩放,以及用于在噪声量子设备上部署的实际模拟。

英文摘要

Fourier analysis has become a crucial tool for understanding the expressivity of Variational Quantum Circuit (VQC) models, as well as an important indicator of barren plateaus (BP). While existing literature has only studied angle-embedded VQCs in a noiseless environment, here we develop the Fourier analysis of VQCs with non-linear data embedding, with particular focus on amplitude embedding, which provides a naturally compact encoding scheme. We first investigate a subtle difference in the domain of input features within amplitude embedding that leads to a distinct expressivity of the zero-frequency Fourier coefficient. By assuming that the ensemble of unitaries generated from the parameter space forms at least a 2-design with respect to the unitary group, we derive, via Weingarten calculus, that the mean of the Fourier coefficients is concentrated at zero, and the variance scales at an exponentially decaying order with respect to the multi-dimensional frequency magnitude. When a noise channel with unitary Kraus operators and probabilities $\{p_k\}$ is taken into account, the variance is further suppressed by a factor $\left(\sum_k p_k^2\right)^{Q}<1$, where $Q$ is the number of channel instances applied. Furthermore, we demonstrate and validate the analytical results through simulations, both noiseless and noisy, including a case where target functions are decomposed into non-integer frequencies, highlighting the practical utility of the approach. Our results establish a rigorous Fourier framework for amplitude-encoded VQCs, offering both theoretical guarantees on expressivity, hence trainability scaling in the frequency domain, as well as practical simulations for deployment on noisy quantum devices.

2606.14205 2026-06-15 cs.IT math.CO 新提交

Block Tensor Rank of Sum-Rank Metric Codes

和秩度量码的块张量秩

Huimin Lao, Huy Pham, Hoang Ta, Van Khu Vu

AI总结 本文引入和秩度量码的块张量秩,证明其可加性分解,并基于投影和坐标码导出下界,构造达到Singleton或Griesmer界的码族。

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AI中文摘要

和秩码为汉明码和秩度量码提供了广义框架,其码字表示为矩阵元组,权重由块秩之和给出。本文引入并研究了和秩度量码的块张量秩不变量。对每个码,我们定义其块张量秩:即线性张成该码所需的最小块简单张量(即支撑在单个块内的秩一矩阵)个数。通常,确定和秩码的块张量秩是困难的。我们的主要结构结果表明,块张量秩在码的块上可加性分解,从而将其计算简化为每个块投影上的张量秩问题。由此,我们推导出块张量秩的两个互补下界,分别称为投影界和坐标码界。此外,通过将坐标码界与汉明度量码的经典Singleton界和Griesmer界相结合,我们分别得到显式下界,称为Singleton坐标码界和Griesmer坐标码界。我们进一步构造了块张量秩达到Singleton或Griesmer坐标码界的和秩码族。这些构造基于达到相应经典界的汉明度量码。最后,我们证明在某些情况下,文献中两个已知和秩码族的块张量秩未能达到Singleton坐标码界。

英文摘要

Sum-rank codes provide a generalized framework for Hamming and rank-metric codes, with codewords represented as tuples of matrices and weight given by the sum of the block ranks. In this paper, we introduce and study a block-tensor-rank invariant for sum-rank metric codes. To each code, we associate its \emph{block tensor rank}: the smallest number of block-simple tensors, namely rank-one matrices supported inside single blocks, whose linear span contains the code. In general, determining the block tensor rank of a sum-rank code is challenging. Our main structural result shows that the block tensor rank decomposes additively across the blocks of the code, thereby reducing its computation to a tensor-rank problem on each block projection. Consequently, we derive two complementary lower bounds on the block tensor rank, referred to as the \emph{projection-wise bound} and the \emph{coordinate-code bound}. Moreover, by combining the coordinate-code bound with the classical Singleton and Griesmer bounds for codes in the Hamming metric, we obtain explicit lower bounds, called the \emph{Singleton coordinate-code bound} and the \emph{Griesmer coordinate-code bound}, respectively. We further construct families of sum-rank codes whose block tensor ranks attain the Singleton or Griesmer coordinate-code bounds. These constructions are based on Hamming-metric codes achieving the corresponding classical bounds. Finally, we show that, in certain cases, the block tensor ranks of two known families of sum-rank codes in the literature do not attain the Singleton coordinate-code bound.

2606.14204 2026-06-15 quant-ph 新提交

Simultaneous Estimation of Partial-Transpose Moments with Active Memory Independent of the Moment Order

与矩阶数无关的主动记忆下部分转置矩的同时估计

Junxiang Huang, Xiaoyang Wang, Xiao Yuan, Yukun Zhang

AI总结 提出一种主动量子记忆约束下同时估计部分转置矩的方法,使用最多2n+1个活跃量子比特(与K无关),以O(K log K/ε²)的副本复杂度实现均匀误差ε,并证明下界Ω(K/ε²)。

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24 pages, 6 figures, 1 table
AI中文摘要

我们研究了在显式主动记忆约束下,从独立副本中同时估计未知二分n量子比特态的部分转置矩$p_j(\rho_{AB})=\mathrm{Tr}[(\rho_{AB}^{T_B})^j]$,$j=2,\ldots,K$的问题。我们给出了一种部分转置置换的顺序量子比特重用实现,该实现最多使用$2n+1$个活跃量子比特,与$K$无关,并以总副本复杂度$O(K\log K/\epsilon^2)$将所有矩$p_2,\ldots,p_K$估计到均匀加性误差$\epsilon$。我们还证明了两个逆界。首先,任何均匀准确的同步估计器在最坏情况下需要$\Omega(K/\epsilon^2)$个副本。其次,相同的标度适用于一个显式的等谱两量子比特负部分转置(NPT)族,其普通矩为常数而部分转置矩变化。这些结果刻画了部分转置矩层次结构的副本复杂度(相差一个对数因子),并将同步非线性泛函估计从普通态幂扩展到在主动量子记忆下与目标矩阶数无关的部分转置谱数据。

英文摘要

We study the simultaneous estimation of partial-transpose moments $p_j(\rho_{AB})=\mathrm{Tr}[(\rho_{AB}^{T_B})^j]$, $j=2,\ldots,K$, of an unknown bipartite $n$-qubit state from independent copies under an explicit active-memory constraint. We give a sequential qubit-reuse realization of the partial-transpose permutation that uses at most $2n+1$ active qubits, independent of $K$, and estimates all moments $p_2,\ldots,p_K$ to uniform additive error $\epsilon$ with total copy complexity $O(K\log K/\epsilon^2)$. We also prove two converse bounds. First, any uniformly accurate simultaneous estimator requires $\Omega(K/\epsilon^2)$ copies in the worst case. Second, the same scaling holds on an explicit isospectral two-qubit negative-partial-transpose (NPT) family whose ordinary moments are constant while the partial-transpose moments vary. These results characterize the copy complexity of the partial-transpose moment hierarchy up to a logarithmic factor and extend simultaneous nonlinear-functional estimation from ordinary state powers to partial-transpose spectral data under active quantum memory independent of the target moment order.

2606.14203 2026-06-15 cs.IT physics.ins-det 新提交

Practical Low-Weight Codes for Energy-Efficient Bus Encoding

用于节能总线编码的实用低权重码

Lorenzo Valentini, Marco Chiani

AI总结 针对最小化连续消息间汉明距离的问题,提出两种基于预定义随机码本的实用编码方案,通过闭式表达式评估平均比特翻转次数,在64位数据加8位冗余时实现约24.7%的翻转减少,接近最优方案的26.4%。

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IEEE International Conference on Communications, 2026
AI中文摘要

我们考虑将数据编码为二进制消息的传输,目标是最小化连续消息之间的汉明距离(即比特翻转次数)。该问题对于增强非易失性存储器的寿命和减少数据总线中由翻转引起的能耗具有重要意义。在文献中,这被称为写高效存储器编码,传统上使用最优但复杂的方案来解决。在低功耗计算机系统中,同一主题被称为总线编码。在本文中,我们推导出闭式表达式来评估实用的次优编码方案的平均比特翻转次数,并提出了两种由预定义随机码本辅助的新方案。我们证明,低复杂度方案能够实现非常接近最优方案的性能,使其在能量敏感和内存关键的应用中具有吸引力。例如,通过向64位数据添加8个额外比特,次优方案可以实现约24.7%的比特翻转减少(与节能相关),而复杂度显著更高的最优方案则提供26.4%的减少。

英文摘要

We consider the transmission of data encoded into binary messages, with the goal of minimizing the Hamming distance, i.e., the number of bit-flips, between consecutive messages. This problem is relevant for enhancing the longevity of Non-Volatile Memories and reducing transition-induced energy consumption in data buses. Known as Write-Efficient Memory coding in the literature, this challenge has traditionally been addressed using optimal but complex schemes. In low-power computer systems the same topic is known as bus encoding. In this paper, we derive closed-form expressions to evaluate the average number of bit-flips for practical, sub-optimal encoding schemes, and propose two new schemes assisted by predefined random codebooks. We demonstrate that low-complexity solutions achieve performance very close to the optimal schemes, making them attractive for implementation in energy-sensitive and memory-critical applications. For instance, by adding 8 extra bits to 64-bits data, sub-optimal schemes can achieve a bit-flip reduction (related to energy saving) of approximately 24.7%, compared to the 26.4% reduction offered by the significantly more complex optimal scheme.

2606.14201 2026-06-15 cs.DB 新提交

TACO: A Benchmark for Open-Domain Text-to-SQL with Ambiguous and Cross-Database Queries

TACO:面向开放域、含歧义和跨数据库查询的文本到SQL基准

Chao Deng, Ju Fan, Yuyu Luo, Qinliang Xue, Meihao Fan, Yuxin Zhang, Min Zhang, Xiaofeng Jia, Jing Zhang, Xiaoyong Du

AI总结 提出TACO基准,包含1500个真实和13000个合成示例,覆盖开放域、歧义和跨数据库查询,通过基线TACO-SQL揭示现有方法的局限性。

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AI中文摘要

文本到SQL旨在将自然语言问题转化为结构化数据库上的可执行SQL查询。现有基准主要关注具有预定义数据库模式和明确问题的封闭域设置,但在应对开放域场景的挑战(如歧义问题、未指定数据库和跨数据库查询)方面存在不足。为弥补这一差距,我们引入了TACO,一个面向开放域、含歧义和跨数据库查询的文本到SQL基准。TACO包含基于智慧城市数据服务的1,500个真实世界文本到SQL示例,以及基于大规模开放数据门户生成的13,000个高质量合成示例,涵盖交通、医疗和金融等多个领域。为构建合成示例,我们开发了一种有效的数据合成流程,保留了真实世界查询的复杂性。为展示TACO的实用性,我们引入了一个基线TACO-SQL,由问题重写、表格链接和查询规划组成,以说明TACO带来的挑战,并更好地理解现有文本到SQL方法的局限性。在TACO上使用多种近期文本到SQL方法进行的大量实验表明,尽管TACO-SQL取得了最佳结果,但现有方法与人工编写的SQL之间仍存在显著差距。这些发现凸显了开放域文本到SQL的难度,并将TACO定位为推动未来研究的有价值基准。

英文摘要

Text-to-SQL aims to translate natural language questions into executable SQL queries over structured databases. Existing benchmarks mainly focus on closed-domain settings with predefined database schemas and well-specified questions, but they fall short in addressing the challenges of open-domain scenarios, such as ambiguous questions, unspecified databases, and cross-database querying. To bridge this gap, we introduce TACO, a benchmark for open-domain Text-to-SQL with Ambiguous and Cross-database queries. TACO consists of 1,500 real-world Text-to-SQL examples based on a smart city data service and 13,000 high-quality synthetic examples generated based on large-scale open data portals, covering diverse domains such as transportation, healthcare, and finance. To construct the synthetic examples, we develop an effective data synthesis pipeline that preserves the complexity of real-world queries. To demonstrate the utility of TACO, we introduce a baseline TACO-SQL composed of question rewriting, table linking, and query planning, to illustrate the challenges posed by TACO and to better understand the limitations of existing Text-to-SQL approaches. Extensive experiments on TACO using a variety of recent Text-to-SQL approaches show that, while TACO-SQL achieves the best results, a significant gap still remains between the existing approaches and human-written SQL. These findings highlight the difficulty of open-domain Text-to-SQL and position TACO as a valuable benchmark to drive future research.

2606.14198 2026-06-15 eess.SY 新提交

SOS-based Stability Verification for Saturated INDI Control of Hybrid-VTOL Aircraft Pitch Rate Dynamics

基于SOS的混合VTOL飞行器俯仰角速率饱和INDI控制稳定性验证

Dalim Wahby, Lorenzo Schenk, Guillaume Ducard

AI总结 针对混合VTOL飞行器的饱和增量非线性动态逆(INDI)俯仰角速率控制器,通过等效循环平衡网络(REN)表示,利用平方和(SOS)规划合成局部Lyapunov函数,获得考虑执行器饱和的吸引域内估计,实现非线性稳定性验证。

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AI中文摘要

增量非线性动态逆(INDI)是一种以鲁棒抗扰性著称的飞行控制策略;然而,其形式化稳定性验证传统上局限于线性化动力学模型。本文通过将INDI控制器表示为等效循环平衡网络(REN),为混合垂直起降(VTOL)飞行器的饱和INDI俯仰角速率控制器提供了形式化非线性稳定性证书。通过将饱和INDI架构转化为REN,闭环动力学被精确映射为增广状态反馈系统。这种结构等价性使得能够利用平方和(SOS)规划合成局部有效的Lyapunov函数,而无需依赖保守的边界近似。所得证书给出了明确考虑执行器饱和的吸引域(RoA)内估计,从而在标准线性裕度失效的运行状态下形式化验证了控制器的稳定性。

英文摘要

Incremental nonlinear dynamic inversion (INDI) is a prominent flight-control strategy valued for its robust disturbance rejection; however, its formal stability verification has traditionally been limited to linearized dynamical models. This paper presents a formal nonlinear stability certificate for a saturated INDI pitch-rate controller for a hybrid vertical take-off and landing (VTOL) aircraft by representing the INDI controller via an equivalent recurrent equilibrium network (REN). By casting the saturated INDI architecture as a REN, the closed-loop dynamics are exactly mapped to an augmented state-feedback system. This structural equivalence enables the use of sum of squares (SOS) programming to synthesize a locally valid Lyapunov function without relying on conservative bounding approximations. The resulting certificate yields an inner estimate of the region of attraction (RoA) that explicitly accounts for actuator saturation, formally verifying the controller's stability in operating regimes where standard linear margins lose their validity.

2606.14197 2026-06-15 astro-ph.HE gr-qc 新提交

Licence to Bin: Accurate and Scalable Inference for Binary Neutron Stars in Next-Generation Gravitational-Wave Detectors

许可二进制:下一代引力波探测器中双中子星的精确与可扩展推断

Nir Guttman, A. Makai Baker, Paul D. Lasky, Eric Thrane

AI总结 针对下一代引力波探测器长时双中子星信号,提出改进的降阶求积方法,结合自适应频率采样、磁盘流和子带构建,首次实现约2小时信号的贝叶斯推断,计算效率高且精度足够。

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Comments
18 pages, 7 figures
AI中文摘要

下一代引力波天文台将以更高的信噪比、更长的持续时间和更宽的频带观测双中子星合并,比当前探测器更优。这些长时信号对贝叶斯参数估计构成了重大计算挑战。降阶求积是一种有前景的加速推断方法,但在这种情况下,其标准构建遇到了严重的内存和精度限制。我们提出了一种实用的降阶求积构建方法,用于具有时变探测器响应和天文台自由光谱范围完整效应的长双中子星信号。我们的方法结合了改进的自适应频率采样、磁盘流和子带降阶求积构建,使得之前难以处理的信号能够高效且准确地建立降阶模型。我们首次在约2小时、低至5 Hz、信噪比为2090的双中子星信号上演示了降阶贝叶斯推断。结果表明,所得到的降阶求积对于实际推断仍然足够准确。完整分析使用128个CPU核心在大约48小时内完成。我们还发现,当包含时变探测器响应效应时,单个宇宙探索者探测器可以将此类信号定位到约41平方度的90%置信天区,这对多信使天文学和宇宙学具有重要意义。这些结果表明,降阶方法可以使下一代双中子星推断在计算上变得可行。

英文摘要

Next-generation gravitational-wave observatories will observe binary neutron-star mergers with much higher signal-to-noise ratios, over much longer durations and across broader frequency bands than current detectors. These long-duration signals present a major computational challenge for Bayesian parameter estimation. Reduced-order quadrature is a promising approach for accelerating inference, but in this regime its standard construction encounters severe memory and accuracy limitations. We present a practical reduced-order quadrature construction for long binary neutron-star signals with time-dependent detector response and full effects of the observatories' free-spectral range. Our approach combines improved adaptive frequency sampling, disk-backed streaming, and subbanded reduced-order quadrature construction, enabling efficient and accurate reduced-order models for signals that were previously intractable. We demonstrate for the first time reduced-order Bayesian inference on an approximately 2 h binary neutron-star signal extending down to 5 Hz and with signal-to-noise ratio 2090. We show the resulting reduced-order quadrature remains sufficiently accurate for practical inference. The full analysis is carried out in about 48 h using 128 CPU cores. We also find that, when time-dependent detector-response effects are included, a single Cosmic Explorer detector can localize such a signal to a 90% credible sky area of approximately $41~\mathrm{deg}^2$, with important implications for multimessenger astronomy and cosmology. These results demonstrate that reduced-order methods can make next-generation binary neutron-star inference computationally feasible.

2606.14196 2026-06-15 cond-mat.str-el cond-mat.mtrl-sci 新提交

Ferromagnetic Order of Reduced Magnetic Moments in a Frustrated Sawtooth Chain of the Magnetic Semiconductor ZnYb$_2$S$_4$

磁性半导体ZnYb$_2$S$_4$中受挫锯齿链中约化磁矩的铁磁序

Shinji Okada, Hiroto Suzuki, Nonoka Higa, Yasuyuki Shimura, Takanori Taniguchi, Takahiro Onimaru

AI总结 研究正交半导体ZnYb$_2$S$_4$中Yb$^{3+}$离子形成的锯齿链的磁性,发现铁磁序但磁矩因几何阻挫而大幅减小。

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Comments
6 pages, 6 figures
AI中文摘要

在锯齿自旋链中,竞争性的最近邻和次近邻相互作用抑制了长程有序,产生了诸如自旋二聚体单态、1/2磁化平台和自旋收缩等新奇量子态。这里,我们研究了正交半导体ZnYb$_2$S$_4$的磁性,其中有效自旋-1/2的Yb$^{3+}$离子沿$b$轴形成锯齿链。比热在${T}_{\rm m}$ $=$ 1.4 K处出现尖锐峰,此时磁熵$S_{\rm m}$仅达到$R$ln2的27%。$T_{\rm m}$处约化的$S_{\rm m}$表明即使在$T$ $>$ $T_{\rm m}$时,Yb$^{3+}$的基态二重态也释放了熵。0.28 K下的等温磁化$M(B)$在$\left|B\right| \leq 0.2$ T时表现出磁滞,并在$B > 0.2$ T时单调增加。自发磁化仅为0.1 ${\it \mu}_{\rm B}$$/$Yb,比Yb$^{3+}$基态二重态的预期值小一个数量级。此外,在粉末中子衍射测量中,对于$T$ $<$ $T_{\rm m}$,未观察到反铁磁序的超晶格反射。因此,在基态中,Yb磁矩呈铁磁排列,但其幅度因锯齿Yb链中的磁阻挫而减小。

英文摘要

In a sawtooth spin chain, competing nearest- and next-nearest-neighbor interactions suppress long-range order, yielding novel quantum states such as a spin-dimer singlet, 1/2 magnetization plateau, and spin contraction. Here, we investigate the magnetic properties of the orthorhombic semiconductor ZnYb$_2$S$_4$, in which Yb$^{3+}$ ions with an effective spin-1/2 form a sawtooth chain along the $b$-axis. The specific heat exhibits a sharp peak at ${T}_{\rm m}$ $=$ 1.4 K, at which the magnetic entropy $S_{\rm m}$ reaches only 27% of $R$ln2. This reduced $S_{\rm m}$ at $T_{\rm m}$ indicates the entropy release of the ground state doublet of Yb$^{3+}$ even for $T$ $>$ $T_{\rm m}$. The isothermal magnetization $M(B)$ at 0.28 K exhibits hysteresis for $\left|B\right| \leq 0.2$ T and increases monotonically for $B > 0.2$ T. The spontaneous magnetization is only 0.1 ${\it \mu}_{\rm B}$$/$Yb, an order of magnitude smaller than that expected for the ground state doublet of Yb$^{3+}$. Moreover, in powder neutron diffraction measurements, no superlattice reflections due to antiferromagnetic order are observed for $T$ $<$ $T_{\rm m}$. Therefore, in the ground state, the Yb moments are ferromagnetically aligned, but their amplitude is reduced by magnetic frustration in the sawtooth Yb chain.