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2606.09282 2026-06-09 eess.SY cs.MA cs.SY 新提交

Revisiting mesoscopic traffic flow simulation in SUMO: Limitations, analysis, and an alternative

重新审视SUMO中的介观交通流仿真:局限性、分析与替代方案

Ying-Chuan Ni, Alina Akopian, Anastasios Kouvelas, Michail A. Makridis

AI总结 针对SUMO中Eissfeldt介观模型不遵循LWR理论的问题,提出基于链路传输模型的离散时间实现,显式考虑后向传播空间以精确捕捉拥堵动态。

Comments Presentation at SUMO Conference 2026

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AI中文摘要

介观交通流模型结合了宏观和微观模型的优点,既能详细捕捉个体车辆行为,又能保持计算效率。在本研究进行时,SUMO(城市交通仿真)使用了Eissfeldt(2004)提出的介观模型。车辆的运动由边缘之间的动态车头时距控制。然而,该模型并不完全符合Lighthill-Whitham-Richards(LWR)模型的原则。发现了若干问题,包括对队列动力学的不完整考虑以及后向传播空间的有限实现。两个案例研究场景表明,这些问题导致了不现实的拥堵形成和恢复模式。使用该模型通常低估了拥堵的严重程度。为了解决这些缺陷,提出了一种遵循LWR原则的链路传输模型的适当介观离散时间实现。通过显式纳入后向传播空间以捕捉队列溢出现象,所提出的模型提供了更精确的拥堵动态表示。链路密度输出与运动波理论和SUMO中的微观交通仿真一致,从而验证了其理论准确性。

英文摘要

Mesoscopic traffic flow models combines the merits of both macroscopic and microscopic models by capturing individual vehicle behavior in great detail and remaining the computational efficiency. At the time of this study, the mesoscopic model proposed by Eissfeldt (2004) is used in Simulation of Urban MObility (SUMO). The movement of vehicles is governed by dynamic headways between edges. However, the model does not fully comply with the principle of the Lighthill-Whitham-Richards (LWR) model. Several problems are identified, including the incomplete consideration of queue dynamics and the limited implementation of backward traveling spaces. Two case study scenarios demonstrate that the problems lead to unrealistic onset and recovery pattern of congestion. The magnitude of congestion is generally underestimated with this model. To address these drawbacks, a proper mesoscopic discrete-time implementation of link transmission model, which follows the LWR principle, is proposed. By explicitly incorporating backward traveling spaces to capture queue spillback phenomena, the proposed model provides a more precise representation of congestion dynamics. The link density outputs are consistent with the kinematic wave theory and the microscopic traffic simulation in SUMO, thus verifying its theoretical accuracy.

2606.09281 2026-06-09 cond-mat.mes-hall cond-mat.mtrl-sci cond-mat.supr-con 新提交

Unconventional incommensurate epitaxy of superconducting FeSe films on SrTiO$_3$

超导FeSe薄膜在SrTiO$_3$上的非常规非公度外延生长

M. Klement, K. M. Fijalkowski, M. Kamp, C. Gould, L. W. Molenkamp

AI总结 通过X射线衍射和透射电镜研究FeSe/FeTe多层膜,发现FeSe与SrTiO$_3$界面缺乏原子匹配,但保持定向对齐,揭示了一种无原子配准的外延新机制。

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Journal ref
Phys. Rev. Materials 10, 064801 (2026)
AI中文摘要

我们通过X射线衍射和透射电子显微镜研究了在SrTiO$_3$(001)衬底上分子束外延生长的超导FeSe/FeTe多层膜。虽然X射线衍射证实了FeSe、FeTe和衬底之间完美的面内外延对齐,但扫描透射电子显微镜揭示了FeSe/SrTiO$_3$界面处原子配准的惊人缺失。FeSe并未适应衬底晶格,而是保持其自身的面内晶格间距。观察到FeSe和SrTiO$_3$原子位置之间的周期性横向偏移,其配准重复长度与X射线衍射确定的晶格失配一致。界面处未检测到失配位错或其他弛豫特征。这种定向对齐与无配准生长的共存表明了一种非常规的外延机制,其中晶体学取向得以保持而无需原子匹配。这些发现为层状系统中的应变调节提供了见解,并可能对铁基超导体的界面工程产生影响。

英文摘要

We present a combined X-ray diffraction and transmission electron microscopy study of superconducting FeSe/FeTe multilayers grown by molecular beam epitaxy on SrTiO$_3$(001) substrates. While X-ray diffraction confirms perfect in-plane epitaxial alignment between FeSe, FeTe, and the substrate, scanning transmission electron microscopy reveals a surprising lack of atomic registry at the FeSe/SrTiO$_3$ interface. Instead of adapting to the substrate lattice, FeSe retains its own in-plane lattice spacing. A periodic lateral shift between the atomic positions of FeSe and SrTiO$_3$ is observed, with a registry recurrence length that matches the lattice mismatch determined by X-ray diffraction. No misfit dislocations or other relaxation features are detected at the interface. This coexistence of directional alignment and registry-free growth suggests an unconventional regime of epitaxy in which crystallographic orientation is maintained without atomic matching. The findings offer insight into strain accommodation in layered systems and may have implications for interface engineering in Fe-based superconductors.

2606.09280 2026-06-09 math.AP math.DG 新提交

The effect of geometric focusing on dispersive estimates for Schrödinger and wave equations

几何聚焦对薛定谔方程和波动方程色散估计的影响

Qiuye Jia, Junyong Zhang

AI总结 本文分类了非捕获渐近锥流形和精确度量锥上薛定谔方程和波动方程色散估计的长期衰减率,揭示了共轭点导致衰减阶损失和正则性指数偏移,并提出了可容许条件避免π距离共轭点对的损失。

Comments Comments welcome

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AI中文摘要

我们根据几何聚焦的强度,分类了非捕获渐近锥流形和精确度量锥上薛定谔方程和波动方程色散估计中的长期衰减率。设$X_0$为度量锥,我们的主要结果之一表明,在$Y=\partial X_0$上距离$\pi$内的每个共轭点重数会导致薛定谔方程色散估计中长期衰减阶的$|t|^{1/2}$损失和正则性指数的半阶偏移。出乎意料的是,当承载波传播的Legendre子流形满足我们提出的自然可容许条件时,$Y$上距离$\pi$的共轭点对不会造成损失。总之,我们给出了一个稳健的框架来证明色散估计,该框架在几何扰动下稳定,并且也适应势的扰动。

英文摘要

We classify the long-time decay rate in dispersive estimates for the Schrödinger and wave equations on non-trapping asymptotically conic manifolds and exact metric cones in terms of the intensity of geometric focusing. Letting $X_0$ be a metric cone, one of our main results demonstrates that each multiplicity of conjugate points within distance $π$ on $Y=\partial X_0$ leads to a $|t|^{1/2}$-loss in the long-time decay order and a half-order shift in the regularity index in the dispersive estimate for the Schrödinger equation. Unexpectedly, conjugate point pairs on $Y$ at distance $π$ do not cause loss when the Legendre submanifold carrying the wave propagation satisfies a natural admissible condition that we propose. In sum, we give a robust framework for proving dispersive estimates that is stable under geometric perturbations and also accommodates perturbations by potentials.

2606.09279 2026-06-09 cs.CE 新提交

Bridging nanoparticle morphology and viscoelastic behavior in epoxy nanocomposites: A coarse-grained simulation-informed constitutive model

桥接纳米颗粒形态与环氧纳米复合材料粘弹性行为:一种粗粒化模拟驱动的本构模型

Atiyeh Hentea, Shadab Zakavatib, Behrouz Arash, Maximilian Jux, Raimund Rolfes

AI总结 提出结合粗粒化分子模拟与实验的框架,开发预测纳米颗粒含量和团聚尺寸对环氧纳米复合材料率温依赖行为影响的本构模型,通过大规模CG模拟实现,并验证其预测能力。

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AI中文摘要

工程应用中对聚合物纳米复合材料在各种热机械载荷条件下材料行为的准确预测需求日益增长。本研究提出一个集成框架,结合粗粒化(CG)分子模拟和实验测试,开发纳米颗粒/环氧纳米复合材料的预测性本构模型。这项工作的关键贡献在于通过大规模CG模拟,表征了纳米颗粒含量和团聚尺寸对纳米复合材料速率和温度依赖行为的影响。所提出的框架成功捕捉了材料响应,包括非线性超弹性、软化行为以及速率和温度依赖特性,覆盖了广泛的应变率、温度、纳米颗粒尺寸和重量分数。使用未参与参数识别的额外实验数据验证了CG模拟驱动的本构模型的预测能力。通过减少对广泛实验测试的依赖同时保持高精度,这种模拟驱动方法为开发用于设计和优化先进纳米复合材料的稳健预测性本构模型提供了高效途径。

英文摘要

Accurate prediction of the material behavior of polymer nanocomposites under various thermomechanical loading conditions is increasingly demanded for engineering applications. This study proposes an integrated framework combining coarse-grained (CG) molecular simulations and experimental testing to develop predictive constitutive models for nanoparticle/epoxy nanocomposites. The key contribution of this work lies in characterizing the influence of nanoparticle content and agglomerate size on the rate- and temperature-dependent behavior of nanocomposites, enabled by large-scale CG simulations. The proposed framework successfully captures the material response, including nonlinear hyperelasticity, softening behavior, and rate- and temperature-dependent properties, across a broad range of strain rates, temperatures, and nanoparticle sizes and weight fractions. The predictive capability of the CG simulation-informed constitutive model is validated using additional experimental data that were not included in the parameter identification process. By reducing reliance on extensive experimental testing while maintaining high accuracy, this simulation-driven approach offers an efficient pathway for developing robust, predictive constitutive models for designing and optimizing advanced nanocomposites.

2606.09277 2026-06-09 cond-mat.mtrl-sci cond-mat.mes-hall 新提交

Layer-parity-defined surface polarization in Nb$_3$Cl$_8$ for excitonic modulation at van der Waals interfaces

Nb$_3$Cl$_8$中层奇偶性定义的表面极化及其在范德华界面激子调制中的应用

Xinyue Huang, Hansheng Xu, Yuchen Gao, Yushen Zhou, Zhijie Ma, Kenji Watanabe, Takashi Taniguchi, Zuxin Chen, Jianqi Huang, Jianpeng Liu, Teng Yang, Youguo Shi, Yu Ye

AI总结 通过开尔文探针力显微镜直接观测到Nb$_3$Cl$_8$薄片中的层依赖极化态,发现奇偶振荡的表面电势,并利用表面极化纹理有效调控MoSe$_2$的激子发射。

Comments 9 pages, 4 figures

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AI中文摘要

层状Nb$_3$Cl$_8$呼吸型kagome晶格中的内禀对称性破缺为实现电极化表面提供了独特机制。在每个单层中,Nb原子的三聚化破坏了反演和镜像对称性,产生面外电偶极子。AB堆叠的α相将相邻层偶极子反铁电排列,使得未补偿的表面极化严格由层奇偶性决定。这里,我们使用开尔文探针力显微镜模式的原子力显微镜,直接观察了剥离的Nb$_3$Cl$_8$薄片中层依赖的极化态,并解析出表面静电势的显著奇偶振荡。除了这种奇偶锁定的反铁电序,我们还识别了层内极化畴,其中呼吸型kagome网络的局部原子重构反转了表面层的面外偶极子,产生类铁电的堆叠构型。通过将单层MoSe$_2$与Nb$_3$Cl$_8$界面结合,我们证明这些表面极化纹理通过畴依赖的界面能带排列和电荷转移有效调制相邻的激子发射。我们的发现确立了Nb$_3$Cl$_8$作为内禀层极化范德华平台,并表明层奇偶性为编程范德华界面的激子和光电子响应提供了强大的结构自由度。

英文摘要

The intrinsic symmetry breaking in the breathing kagome lattice of layered Nb$_3$Cl$_8$ provides a unique mechanism for realizing electrically polar surfaces. In each monolayer, the trimerization of Nb atoms breaks inversion and mirror symmetries, generating an out-of-plane electric dipole. The AB-stacked $α$ phase arranges adjacent layer dipoles antiferroelectrically, leaving the uncompensated surface polarization strictly governed by layer parity. Here, using atomic force microscopy operated in Kelvin probe force microscopy mode, we directly visualize layer-dependent polarization states in exfoliated Nb$_3$Cl$_8$ flakes and resolve a pronounced odd-even oscillation of the surface electrostatic potential. Beyond this parity-locked antiferroelectric order, we further identify intralayer polar domains in which local atomic reconstructions of the breathing kagome network reverse the out-of-plane dipole of the surface layer, producing ferroelectric-like stacking configurations. By interfacing monolayer MoSe$_2$ with Nb$_3$Cl$_8$, we demonstrate that these surface-polarization textures effectively modulate adjacent excitonic emission through domain-dependent interfacial band alignment and charge transfer. Our findings establish Nb$_3$Cl$_8$ as an intrinsic layer-polarized van der Waals platform and show that layer parity provides powerful structural degree of freedom for programming excitonic and optoelectronic responses at van der Waals interfaces.

2606.09275 2026-06-09 math.NA cs.NA 新提交

An implicit octree-based adaptive Material Point Method

基于隐式八叉树的自适应物质点法

Robert E. Bird, William M. Coombs, Charles E. Augarde, Giuliano Pretti, Ted J. O'Hare

AI总结 提出首个基于八叉树的隐式物质点法,通过自适应网格和物质点离散化高效求解大变形连续体-结构接触问题,实现最高5.5倍加速和21倍CO2减排。

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AI中文摘要

物质点法为模拟刚体结构与周围连续体之间接触相互作用引起的大变形提供了有效方法。然而,求解这些问题需要准确表示连续体-结构界面,这要求高分辨率的背景网格和物质点离散化。这一要求,加上不断演变的连续体-结构界面以及大多数物质点法实现依赖于结构化网格的事实,可能导致大规模数值系统和长时间运行,尤其是在三维问题建模中。受此问题驱动,本文首次提出了基于八叉树的隐式物质点法,用于高效求解大变形连续体-结构相互作用问题。八叉树背景网格提供了一种自然的方式,基于结构与连续体之间相互作用的位置自动调整计算网格和物质点离散化。该新方法在多个大变形基准问题和连续体-结构相互作用问题上进行了验证,与使用一致网格获得的结果相比,在HPC上运行时实现了高达5.5倍的加速和随之而来的21倍CO2减排。

英文摘要

The Material Point Method provides an effective approach for modelling the large deformations that often arise from contact interactions between rigid structures and surrounding continua. However, solving these problems requires accurate representation of the continuum-structure interface, which necessitates high resolution background mesh and material point discretisations. This requirement, combined with evolving continuum-structure interfaces and the fact that most Material Point Method implementations are dependent on structured meshes, can result in large numerical systems and long run times especially when modelling problems in three-dimensions. Motivated by this issue, this paper provides the first octree-based implicit Material Point Method for efficient solution of large deformation continuum-structure interaction problems. The octree background mesh provides a natural way to automatically adapt both the computational mesh and the material point discretisation based on the position of the interaction between the structure and continuum. The new approach is demonstrated on a number of large deformation benchmark and continuum-structure interaction problems, where up to a 5.5-times speed up and a consequent 21-times CO2 saving is achieved when running on a HPC compared to results obtained using a conforming mesh.

2606.09274 2026-06-09 q-fin.RM q-fin.ST stat.ME 新提交

Reverse Stress Testing for Multivariate Scenarios: A Conditional Framework for Stressed Time Series

多变量场景的反向压力测试:压力时间序列的条件框架

Michele Sparviero, Lorenzo Viola

AI总结 提出一种反向压力测试方法,从单一资产类别的外生冲击出发,重建与市场经验依赖结构一致的多变量压力场景,并通过三种分布假设下的条件密度最大化求解。

Comments 26 pages, 5 figures, 2 tables

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AI中文摘要

本文开发了一种反向压力测试(RST)的方法框架,其中从单一资产类别上施加的外生冲击出发,重建与市场经验依赖结构一致的多变量压力场景。该问题被表述为在给定冲击下条件密度的最大化,并在三种逐渐减弱的分布假设下求解。在参数设置中,收益的联合高斯性产生了一个封闭形式的模态场景,该场景与非冲击分量的条件均值一致。在半参数设置中,通过经验似然方法非参数地估计模态场景,并通过高斯或学生t局部采样方案生成周围的压力轨迹。在完全非参数设置中,通过在估计场景的马氏邻域内对历史观测进行逆距离重采样来获得压力轨迹。这三种变体在实际市场数据上得到了验证。模拟的场景在经济上是一致的,并且能够再现压力市场体制中观察到的标准风险-回报不对称性。

英文摘要

This paper develops a methodological framework for reverse stress testing (RST) in which a multivariate stress scenario, coherent with the empirical dependence structure of a market, is reconstructed from a single exogenous shock prescribed on one asset class. The problem is formulated as the maximisation of the conditional density given the imposed shock, and is solved under three progressively weaker distributional assumptions. In the parametric setting, joint Gaussianity of the returns yields a closed-form modal scenario coinciding with the conditional mean of the non-shocked components. In the semiparametric setting, the modal scenario is estimated nonparametrically through the empirical likelihood methodology and the surrounding stressed trajectories are generated via a Gaussian or Student-t local sampling scheme. In the fully nonparametric setting, stressed trajectories are obtained by inverse-distance resampling of the historical observations within a Mahalanobis neighbourhood of the estimated scenario. The three variants are validated on real market data. The simulated scenarios prove to be economically coherent and capable of reproducing the standard risk-reward asymmetry observed in stressed market regimes.

2606.09272 2026-06-09 math.PR 新提交

A Guided Tour of the Equations of Nonlinear Filtering for Diffusion Processes

扩散过程非线性滤波方程导览

Fabien Campillo, Myriam Corso

AI总结 本文以教学方式介绍扩散过程的非线性滤波,通过状态-观测模型、马尔可夫半群、无穷小生成元和测度变换等工具,推导Kallianpur-Striebel公式、Zakai方程和Kushner-Stratonovich方程,强调直观理解与核心概念。

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AI中文摘要

这些教学笔记介绍了扩散过程的非线性滤波。非线性滤波的目标是从部分且带噪声的观测中估计未观测的随机状态,从而刻画给定观测历史下状态的条件分布。在介绍状态-观测模型之后,我们发展了理论的主要工具,包括马尔可夫半群、无穷小生成元和测度变换方法。这自然引出了Kallianpur-Striebel公式、非归一化滤波器的Zakai方程以及归一化滤波器的Kushner-Stratonovich方程。本讲义在很大程度上遵循了Bain和Crisan的《随机滤波基础》的经典阐述,同时特别强调直觉、动机以及主要概念和方程的解释。许多技术论证被重新审视,并附有额外的细节和评论,以方便读者对该主题的初次阅读。这些笔记无意成为随机滤波的详尽论述,而是旨在提供对其核心思想、方法和方程的一个导览。

英文摘要

These pedagogical notes provide an introduction to nonlinear filtering for diffusion processes. The objective of nonlinear filtering is to estimate an unobserved stochastic state from partial and noisy observations, and thereby characterize the conditional distribution of the state given the observation history. After introducing the state-observation model, we develop the main tools of the theory, including Markov semigroups, infinitesimal generators, and change-of-measure methods. This leads naturally to the Kallianpur-Striebel formula, the Zakai equation for the unnormalized filter, and the Kushner-Stratonovich equation for the normalized filter. The presentation follows, to a large extent, the classical exposition of Bain and Crisan's "Fundamentals of Stochastic Filtering", while placing particular emphasis on intuition, motivation, and the interpretation of the main concepts and equations. Many technical arguments are revisited, with additional details and comments intended to facilitate a first reading of the subject. These notes are not intended to be an exhaustive account of stochastic filtering. Their aim is instead to provide a guided tour of some of its central ideas, methods, and equations.

2606.09270 2026-06-09 math.FA 新提交

O'Neil-type inequalities in Morrey spaces on the set T^n

环面 T^n 上 Morrey 空间中的 O'Neil 型不等式

Ussentay A. B., Sadykova K. K

AI总结 本文在 n 维环面上的局部和广义 Morrey 空间中研究 O'Neil 型卷积不等式,通过二进分解推广了 O'Neil 不等式,并得到了卷积算子的有界性结果。

Comments 7 paged, 0 figures

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AI中文摘要

本文研究了 n 维环面上的局部和广义 Morrey 空间中的 O'Neil 型卷积不等式。我们将经典的 Minkowski 和 Young 不等式推广到 Morrey 空间,并得到了卷积算子的有界性结果。主要结果是通过二进分解将 O'Neil 不等式从 Lorentz 空间推广到 Morrey 型空间。我们推导了不同参数下 Morrey 空间之间卷积算子的范数估计,并刻画了保证有界性的指数允许范围。证明依赖于 Morrey 空间的内插理论、Köthe 对偶性和实内插方法。我们还建立了局部和广义 Morrey 空间之间的嵌入关系。这些结果推广了经典卷积不等式,统一了 Lorentz 和 Morrey 框架,并应用于偏微分方程和调和分析。

英文摘要

This paper studies O'Neil-type convolution inequalities in local and generalized Morrey spaces on the n-dimensional torus. We extend classical Minkowski and Young inequalities to the Morrey setting and obtain boundedness results for convolution operators. The main result is a generalization of O'Neil's inequality from Lorentz spaces to Morrey-type spaces via dyadic decompositions. We derive norm estimates for convolution operators between Morrey spaces with different parameters and characterize the admissible range of exponents ensuring boundedness. The proof relies on interpolation theory for Morrey spaces, Köthe duality, and real interpolation methods. We also establish embedding relations between local and generalized Morrey spaces. These results extend classical convolution inequalities and unify Lorentz and Morrey frameworks, with applications to partial differential equations and harmonic analysis.

2606.09269 2026-06-09 math.AP math.FA 新提交

Analysis of the Quasi-Static Maxwell Equations in Resistive Solid-State Particle Detectors

阻性固态粒子探测器中准静态麦克斯韦方程的分析

Alessandro Rosa

AI总结 通过将权重势分解为静态和动态分量,解决了阻性固态粒子探测器中准静态麦克斯韦方程组的混合边值问题,并建立了内部正则性结果。

Comments 26 pages, 1 figure

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AI中文摘要

我们求解了由准静态近似下的麦克斯韦方程组导出的边值问题,该问题控制着阻性固态粒子探测器中所谓权重势 $V_{\mathrm{w}}(t,x)$ 的时间演化。该模型简化为三阶时间相关偏微分方程 $$ \varepsilon\,\partial_t ΔV_{\mathrm{w}}(t,x) + \mathrm{div}\,\big(σ(x)\nabla V_{\mathrm{w}}(t,x)\big)=0 \quad\text{in } [0,T]\timesΩ,$$ 并补充了可能退化的混合 Neumann-Dirichlet 边界条件。我们的分析基于将权重势分解为静态和动态分量。静态部分求解一致椭圆混合边值问题,而动态部分满足退化抛物型柯西问题。我们还建立了内部正则性结果。

英文摘要

We solve a boundary value problem arising from Maxwell's equations in the quasi-static approximation, which governs the time evolution of the so-called weighting potential $V_{\mathrm{w}}(t,x)$ in resistive solid-state particle detectors. The model reduces to the third-order time-dependent PDE $$ \varepsilon\,\partial_t ΔV_{\mathrm{w}}(t,x) + \mathrm{div}\,\big(σ(x)\nabla V_{\mathrm{w}}(t,x)\big)=0 \quad\text{in } [0,T]\timesΩ,$$ supplemented with mixed Neumann-Dirichlet boundary conditions, possibly degenerate. Our analysis is based on the decomposition of the weighting potential into a static and a dynamic component. The static part solves a uniformly elliptic mixed boundary value problem, while the dynamic part satisfies a degenerate parabolic Cauchy problem. We also establish interior regularity results.

2606.09267 2026-06-09 cond-mat.mes-hall cond-mat.str-el 新提交

Non-Bloch band theory of boundary-controlled magnon edge modes in an antiferromagnetic chain

反铁磁链中边界控制磁子边缘模式的非布洛赫能带理论

Suman Debnath, Sonu Verma, Rohit Mukherjee, Arijit Kundu

AI总结 通过非布洛赫能带理论定义绕数,揭示一维反铁磁自旋链中磁子边缘模式的起源,并展示边界扰动可调控这些模式,解决传统体-边界对应失效问题。

Comments 12 pages. Comments welcome

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AI中文摘要

我们在非布洛赫能带理论框架内定义了一个绕数,该绕数捕捉了一维反铁磁自旋链中磁子边缘模式的出现,即使传统的布洛赫绕数是平凡的。在线性自旋波理论中,磁子激发由非厄米动力学矩阵控制,尽管底层哈密顿量是厄米的。该矩阵的对称性分类给出了平凡的体不变量,然而有限系统表现出边界局域模式,表明传统体-边界对应的失效。我们进一步展示了这些边缘模式可以通过边界扰动来控制。通过调节边界势,这些模式可以被驱动进入或离开体谱。为了解决体-边界不匹配,我们基于广义布里渊区和绕数发展了一个非布洛赫框架,该绕数正确预测了边缘态的存在。我们的结果建立了边界控制的拓扑相变,这些相变可以通过局域塞曼场或反铁磁范德华纳米结构中的修正边缘各向异性在实验上实现。

英文摘要

We define a winding number within the Non-Bloch band theory framework that captures the emergence of magnon edge modes in a one-dimensional antiferromagnetic spin chain, even when the conventional Bloch winding number is trivial. Within linear spin-wave theory, magnon excitations are governed by a non-Hermitian dynamic matrix, despite the underlying Hamiltonian being Hermitian. The symmetry classification of this matrix yields a trivial bulk invariant, however, finite systems exhibit boundary-localized modes, signaling a breakdown of the conventional bulk-boundary correspondence. We further show that these edge modes can be controlled via boundary perturbations. By tuning the boundary potential, the modes can be driven into or out of the bulk spectrum. To resolve the bulk-boundary mismatch, we develop a non-Bloch framework based on a generalized Brillouin zone and a winding number that correctly predicts the presence of edge states. Our results establish boundary-controlled topological transitions that are experimentally accessible through local Zeeman fields or modified edge anisotropy in antiferromagnetic van der Waals nanostructures.

2606.09265 2026-06-09 cond-mat.soft cond-mat.mtrl-sci 新提交

Curvature-guided topology and self-assembly in chiral nematics and liquid-crystal colloids

手性向列相和液晶胶体中的曲率引导拓扑与自组装

Ivan I. Smalyukh, Mykola Tasinkevych

AI总结 综述了液晶胶体和受限向列相中曲率如何产生拓扑缺陷和孤子结构,并基于亏格、欧拉特征、锚定和手性提出统一框架,探讨其在自组装和功能材料中的应用。

Comments 43 pages, 24 figures

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AI中文摘要

在软凝聚态物质中,曲率不仅仅扭曲有序介质:它有助于选择缺陷结构、重新分布弹性应力、偏置手性并引导自组装。本综述考察了液晶胶体和受限向列相中弯曲、多连通和结状边界如何产生拓扑缺陷和局域孤子纹理,以及这些结构如何介导介观尺度构建块之间的相互作用。我们引入一个基于亏格、欧拉特征、锚定和手性的统一框架,并用它来讨论球形、手柄体和带边界胶体,以及具有非平凡拓扑的液滴和聚合物分散向列相。特别强调了几何和拓扑在确定boojums、向错环、hedgehog电荷以及链接和结状缺陷结构中的相互作用。然后我们转向手性系统,其中包含斯格明子、torons、hopfions和相关局域纹理,突出了手性和限制如何稳定三维拓扑态。最后,我们讨论了这些概念如何转化为可控自组装、模板化和功能复合材料的设计原则。更广泛地说,我们认为液晶胶体和受限向列相提供了实验上可访问的模型系统,其中曲率、拓扑和手性可以作为可编程工具来设计有序软物质。

英文摘要

In soft condensed matter, curvature does more than simply distort an ordered medium: it helps select defect structures, redistribute elastic stress, bias chirality, and guide self-assembly. This review examines how curved, multiply connected, and knotted boundaries in liquid-crystal colloids and confined nematics generate topological defects and localized solitonic textures, and how these structures mediate interactions between mesoscale building blocks. We introduce a unifying framework based on genus, Euler characteristic, anchoring, and chirality, and use it to discuss spherical, handlebody, and boundary-bearing colloids, together with droplets and polymer-dispersed nematics of nontrivial topology. Particular emphasis is placed on the interplay of geometry and topology in determining boojums, disclination loops, hedgehog charges, and linked and knotted defect structures. We then turn to chiral systems hosting skyrmions, torons, hopfions, and related localized textures, highlighting how chirality and confinement stabilize three-dimensional topological states. Finally, we discuss how these concepts translate into design principles for controlled self-assembly, templating, and functional composite materials. More broadly, we argue that liquid-crystal colloids and confined nematics provide experimentally accessible model systems in which curvature, topology, and chirality can be harnessed as programmable tools for designing organized soft matter.

2606.09264 2026-06-09 eess.SP 新提交

Block-Term Decomposition Approach to Blind Multi-trial Functional Ultrasound Unmixing

块项分解方法用于盲多试验功能超声分离

Sofia-Eirini Kotti, Eleftherios Kofidis, Borbála Hunyadi

AI总结 提出基于块项张量分解的卷积模型,从多试验fUS数据中盲分离神经源并解卷积血流动力学响应,通过交替投影梯度下降优化,仿真验证了空间图恢复和激活时间估计的准确性。

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AI中文摘要

功能超声(fUS)因其高时空分辨率、低成本和潜在便携性而成为一种强大的神经成像模态。然而,fUS信号仅通过神经血管耦合提供神经元活动的间接观测,因此需要盲分离潜在神经源并解卷积其血流动力学响应。在这项工作中,我们提出了一种基于数据驱动的卷积块项张量分解模型,用于多试验fUS测量,其中每个源具有时空表示,包括低秩空间图和分段常数神经元激活信号,该信号与具有生理合理形状的试验和源依赖的血流动力学响应函数(HRF)卷积。我们提出了一个约束优化框架用于模型计算,包括交替投影梯度下降迭代。仿真结果表明,在各种噪声水平下,空间图的准确恢复和激活时间轮廓的可靠估计,同时确认HRF估计仍然是问题中最具挑战性的部分。

英文摘要

Functional ultrasound (fUS) has emerged as a powerful neuroimaging modality due to its high resolution in both space and time, low cost and potential portability. Nevertheless, fUS signals provide only indirect observations of neuronal activity through the neurovascular coupling, and hence require the blind separation of latent neuronal sources while also deconvolving their hemodynamic responses. In this work, we propose a data-driven convolutive block-term tensor decomposition-based model for multi-trial fUS measurements, where each source has a spatiotemporal representation comprising a low-rank spatial map and a piecewise-constant neuronal activation signal convolved with a trial- and source-dependent hemodynamic response function (HRF) with a physiologically plausible shape. We propose a constrained optimization framework for the model computation, which consists of alternating projected gradient descent iterations. Simulation results are reported that demonstrate accurate recovery of spatial maps and reliable estimation of activation temporal profiles across various noise levels, while confirming that HRF estimation remains the most challenging part of the problem.

2606.09263 2026-06-09 math.DG math-ph math.MP 新提交

Jet Bundles as Higher-Order Polarised $k$-Contact Manifolds

射流丛作为高阶极化 $k$-切触流形

Javier de Lucas

AI总结 本文证明射流丛的Cartan分布是$k$-切触分布,通过引入极化概念给出射流几何的$k$-切触刻画,并应用于偏微分方程。

Comments 61 pages

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AI中文摘要

设 $\pi:E\to Q$ 是一个纤维流形,其中 $\dim Q=n$,秩为 $m$。我们证明 $J^r\pi$ 上的 Cartan 分布 $C^r_\pi$ 是一个 $N^r_\pi$-切触分布,其中 $N^r_\pi=m\binom{n+r-1}{r-1}$,通过给出 $N^r_\pi$-切触形式的自然局部构造。这恢复了 $J^r\pi$ 的典范结构和 Spencer 收缩等结构。它还给出了 $J^r\pi$ 上的自然局部哈密顿结构,恢复并将特征的标准理论推广到 Cartan 分布的一般李对称性。\n我们引入了 $k$-切触分布的新极化类。这引出了我们的主要识别定理,该定理表明,极化 $k$-切触流形局部等价于有限阶射流丛及其 Cartan 分布,当且仅当其极化为射流型。这刻画了有限阶射流几何为射流型的极化 $N_\pi^r$-切触几何。此外,最高阶垂直极化、符号空间、垂直和水平微分、完整子流形以及微分方程的初始条件都通过 $k$-切触几何重建。例如,适应坐标成为 $k$-切触 Darboux 坐标,PDE 的解被视为极化 Legendrian 子流形,射流延拓被恢复为极化 Legendrian 延拓,等等。\n所得形式化对射流几何的多个部分给出了更深的几何理解,为在单一固定射流表示中笨拙的构造(如 Bäcklund 变换)提供了统一的内蕴语言,并允许射流理论扩展到新问题。特别是,我们的技术为 PDE 提供了非常一般的约化方法。结果应用于具有数学和物理相关性的 PDE。

英文摘要

Let $π:E\to Q$ be a fibred manifold, with $\dim Q=n$ and rank $m$. We prove that the Cartan distribution $C^r_π$ on $J^rπ$ is an $N^r_π$-contact distribution, where $N^r_π=m\binom{n+r-1}{r-1}$, by giving a natural local construction of an $N^r_π$-contact form. This recovers the canonical structure of $J^rπ$ and the Spencer contractions, among other structures. It also yields a natural local Hamiltonian structure on $J^rπ$, recovering and extending the standard theory of characteristics to general Lie symmetries of the Cartan distribution. We introduce new classes of polarisations for $k$-contact distributions. This leads to our main recognition theorem, which shows that a polarised $k$-contact manifold is locally equivalent to a finite-order jet bundle with its Cartan distribution precisely when its polarisation is of jet type. This characterises finite-order jet geometry as polarised $N_π^r$-contact geometry of jet type. Moreover, the highest-order vertical polarisation, the symbol spaces, the vertical and horizontal differentials, holonomic submanifolds, and initial conditions for differential equations are reconstructed via $k$-contact geometry. For instance, adapted coordinates become $k$-contact Darboux coordinates, solutions of PDEs are treated as polarised Legendrian submanifolds, jet prolongations are recovered as polarised Legendrian prolongations, and so on. The resulting formalism gives a deeper geometric understanding of several parts of jet geometry, provides a uniform intrinsic language for constructions that are awkward in a single fixed jet presentation, such as Bäcklund transformations, and allows jet theory to be extended to new problems. In particular, our techniques provide very general reduction methods for PDEs. The results are applied to PDEs with mathematical and physical relevance.

2606.09260 2026-06-09 cond-mat.mtrl-sci 新提交

The impact of interfacial chemistry on the band offset of GaAs/Ga$_2$O$_3$ heterostructures

界面化学对GaAs/Ga$_2$O$_3$异质结构能带偏移的影响

Sofia Apergi, Alfredo Pasquarello, Charles Cornet, Laurent Pedesseau

AI总结 采用杂化密度泛函理论系统研究GaAs/Ga$_2$O$_3$界面的能带排列,发现界面化学计量决定排列类型:Ga-O富集界面呈II型排列,As和As-O富集界面呈I型排列,归因于界面偶极形成。

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AI中文摘要

Ga$_2$O$_3$/GaAs异质结正成为下一代电力电子、光子学和能源器件的有前景候选材料,利用了Ga$_2$O$_3$的高击穿电压和热稳定性以及GaAs的成熟技术、高空穴迁移率和更高折射率。这些器件的效率强烈依赖于两种材料之间的能带排列,然而文献中对于这些异质结构同时报道了I型和II型排列。为了解决这一歧义,我们使用杂化密度泛函理论系统研究GaAs/Ga$_2$O$_3$界面的能带排列,重点关注界面化学的作用。通过考虑非晶和晶态Ga$_2$O$_3$相中Ga-O富集、As富集和As-O富集界面,我们证明界面化学计量决定了排列类型:Ga-O富集界面呈现II型排列,具有大的价带偏移(~3.1 eV),而As富集和As-O富集界面倾向于I型排列,具有减小的偏移(~2.3-2.6 eV)。这些趋势归因于由键合构型驱动的界面偶极形成。我们的发现提供了对GaAs/Ga$_2$O$_3$异质结构中化学与能带排列之间关系的洞察,使得能够针对特定器件应用进行定向优化。

英文摘要

Ga$_2$O$_3$/GaAs heterojunctions are emerging as promising candidates for next-generation power electronics, photonics, and energy devices, leveraging the high breakdown voltage and thermal stability of Ga$_2$O$_3$ alongside the mature technology, high hole mobility, and higher refractive index of GaAs. The efficiency of these devices depends strongly on the band alignment between the two materials, however both type-I and type-II alignment have been reported in the literature for these heterostructures. To address this ambiguity, we use hybrid density functional theory to systematically investigate the band alignment at GaAs/Ga$_2$O$_3$ interfaces, focusing on the role of interface chemistry. By considering Ga-O-, As-, and As-O-rich interfaces both in amorphous and crystalline Ga$_2$O$_3$ phases, we demonstrate that interface stoichiometry determines the alignment type: Ga-O-rich interfaces exhibit type-II alignment with large valence band offsets (~3.1 eV), while As-rich and As-O-rich interfaces favor type-I alignment with reduced offsets (~2.3-2.6 eV). These trends are attributed to interface dipole formation driven by bonding configuration. Our findings provide insight into the relationship between chemistry and band alignment in GaAs/Ga$_2$O$_3$ heterostructures, enabling targeted optimization for specific device applications.

2606.09259 2026-06-09 math.GN 新提交

Pseudocompact Topological \(MV\)-Algebras

伪紧拓扑 MV-代数

Li-Hong Xie, Jiang Yang

AI总结 研究伪紧拓扑MV-代数的性质,利用Mal'tsev空间理论和Reznichenko-Uspenskij定理证明任意族伪紧拓扑MV-代数的积仍伪紧,并建立Stone-Čech紧化与商结构。

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AI中文摘要

近年来,多位数学家研究了拓扑MV-代数。本文发现每个拓扑MV-代数都是Mal'tsev于1954年引入的Mal'tsev空间。因此,应用Reznichenko和Uspenskij关于伪紧Mal'tsev空间的定理,我们证明了任意一族伪紧拓扑MV-代数的积是伪紧的。我们还证明了每个σ-紧拓扑MV-代数是ccc的。其次,我们得到伪紧拓扑MV-代数的Stone-Čech紧化具有自然的紧拓扑MV-代数结构,且该结构扩展了原结构。最后,我们证明:设I是伪紧拓扑MV-代数A中的闭理想,且ι_1:A↪βA是自然单射;则cl_{βA}ι_1(I)是βA的闭理想,且βA/cl_{βA}ι_1(I)≅β(A/I)。

英文摘要

Recently, topological MV-algebras have been investigated by several mathematicians. In this paper, we find that every topological \(MV\)-algebra is a Mal'tsev space introduced by Mal'tsev in 1954. Hence, applying the theorem of Reznichenko and Uspenskij on pseudocompact Mal'tsev spaces, we show that the product of arbitrary family of pseudocompact topological \(MV\)-algebras are pseudocompact. We also prove that every $σ$-compact topological \(MV\)-algebra is ccc. Secondly, we obtain that the Stone-Čech compactification of a pseudocompact topological \(MV\)-algebra carries a natural compact topological \(MV\)-algebra structure extending the original one. Finally, we prove that: let \(I\) be a closed ideal in a pseudocompact topological \(MV\)-algebra \(A\) and \(ι_1:A\hookrightarrow\bet A\) is the naturally injective; then \(\cl_{βA}ι_1(I)\) is a closed ideal of \(βA\) and \( βA/\cl_{βA}ι_1(I)\cong β(A/I)\).

2606.09254 2026-06-09 hep-ph hep-ex hep-lat nucl-ex nucl-th 新提交

Meson-Nucleus Bound States with Neural-Network Quantum States

介子-原子核束缚态与神经网络量子态

Wei-Lin Wu, Liang-Zhen Wen, Shi-Lin Zhu

AI总结 基于HAL QCD近物理点介子-核子势,利用神经网络变分蒙特卡罗方法首次系统计算了φ、η_c和J/ψ与原子核(A≤12)的基态,发现束缚态形成阈值和结合能特征,预言了介子对核子分布的压缩及从晕到嵌入的演化。

Comments 12 pages, 6 figures

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AI中文摘要

我们首次基于HAL QCD近物理点介子-核子势,系统计算了φ、η_c和J/ψ与原子核(质量数A≤12)的基态。采用推广至包含介子自由度的神经网络变分蒙特卡罗框架求解(A+1)体薛定谔方程。在从^2H到^{12}C的轻核上基准测试得到的基态能量与实验一致。介子-原子核束缚态出现在:φ在A≥2时,J/ψ在A≥4时,η_c在A≥6时。φ-核系统束缚最强,结合能达到数十MeV。J/ψ-核和η_c-核系统分别在几MeV和亚MeV量级弱束缚。对于粲偶素系统,每核子结合能随A几乎线性加深,而φ-核系统呈现非单调行为,在^4He处达到峰值——这是短程强吸引φN相互作用的独特标志。介子压缩了相对于母核的核子分布,并随A增大从晕结构演变为嵌入核内。我们的结果为未来实验搜索提供了预言,并在格点QCD介子-核子相互作用与介子-原子核束缚态中涌现的多体现象之间建立了定量桥梁。

英文摘要

We present the first systematic calculations of $ϕ$-, $η_c$-, and $J/ψ$-nucleus ground states up to mass number $A{=}12$ based on the HAL QCD meson-nucleon potentials at near-physical point. The $(A{+}1)$-body Schrödinger equation is solved with a neural-network variational Monte Carlo framework, generalized to incorporate mesonic degrees of freedom. Benchmarking on light nuclei from $^2$H to $^{12}$C yields ground-state energies consistent with experiment. Meson-nucleus bound states emerge at $A\ge2$ for $ϕ$, $A\ge4$ for $J/ψ$, and $A\ge6$ for $η_c$. The $ϕ$-nucleus systems exhibit the strongest binding, with binding energies reaching tens of MeV. The $J/ψ$-nucleus and $η_c$-nucleus systems are weakly bound at the few-MeV and sub-MeV scale, respectively. The binding energy per nucleon deepens nearly linearly with $A$ for charmonium systems, whereas the $ϕ$-nucleus system exhibits a non-monotonic behavior peaking at $^4$He -- a distinctive hallmark of the short-range and strongly attractive $ϕN$ interaction. The meson compresses the nucleon distribution relative to the parent nucleus, and evolves from a halo configuration to one embedded inside the nucleus with increasing $A$. Our results provide predictions for future experimental searches, and establish a quantitative bridge between lattice QCD meson-nucleon interactions and the emergent many-body phenomena in meson-nucleus bound states.

2606.09252 2026-06-09 astro-ph.SR 新提交

A consistency check for the calibration of 5303Å solar coronal emission line observations with Aditya-L1/VELC

Aditya-L1/VELC 5303Å 太阳日冕发射线观测定标的一致性检验

V. Muthu Priyal, R. Ramesh, Jagdev Singh, K. Sasikumar Raja, P. Savarimuthu

AI总结 本文利用太阳自身观测对 Aditya-L1 上的 VELC 进行 5303Å 辐射定标,并通过天狼星 A 观测验证,结果表明日冕亮度测量及绝对物理单位转换可靠,同时测量了 VELC 的点扩散函数。

Comments Accepted for publication in Solar physics

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AI中文摘要

我们利用太阳本身的观测,对 Aditya-L1 上的可见发射线日冕仪(VELC)在 5303Å 处进行了辐射定标,这是一种与其他目前运行中的空间太阳日冕仪使用亮星定标不同的新方法。测量得到的 VELC 探测器计数对应于太阳盘面中心,约为 $(1.70\pm0.12)\times10^{8}\\, \rm sec^{-1}Å^{-1}$,这与太阳在 1 AU 处 5303Å 的通量 $\approx3.0456\times10^{6}\\, \rm {erg\\,sec^{-1} cm^{-2} Å^{-1}}$ 相关。我们利用亮星天狼星 A 的观测验证了上述定标,其在 1 AU 处 5303Å 的估计通量约为 $\approx1.44\times10^{-8}\\,\mathrm{erg\\,sec^{-1} cm^{-2} Å^{-1}}$。VELC 在此情况下的预期探测器计数约为 $\approx19\pm1.4\\, \rm sec^{-1}Å^{-1}$,而测量计数约为 $\approx23\pm0.4\\, \rm sec^{-1}Å^{-1}$。在 VELC 运行两年后进行的初步一致性检验中,天狼星 A 的预期值与观测值合理吻合,表明利用 VELC 在 5303Å 处测量日冕亮度并利用太阳盘面光观测将其转换为绝对物理单位的方法是可行的。利用天狼星 A 的观测,我们还测量了 VELC 在其 5303Å 通道的点扩散函数(PSF)。其半高全宽(FWHM)约为 $3.8^{\prime\prime}$。

英文摘要

We carried out radiometric calibration of the Visible Emission Line Coronagraph (VELC) onboard Aditya-L1 at 5303Å using observations of the Sun itself, a novel approach compared to the calibration using bright stars in the other currently operational space solar coronagraphs. The measured VELC detector count corresponding to the center of Sun's disk is ${\approx}(1.70{\pm}0.12){\times}10^{8}\, \rm sec^{-1}Å^{-1}$, which relates to Sun's flux at 1\,AU in 5303Å, ${\approx}3.0456{\times}10^{6}\, \rm {erg\,sec^{-1} cm^{-2} Å^{-1}}$. We verified the above calibration using observations of the bright star Sirius-A whose estimated flux at 1\,AU in 5303Å is ${\approx}1.44{\times}10^{-8}\,\mathrm{erg\,sec^{-1} cm^{-2} Å^{-1}}$. The expected detector count with VELC in this case is ${\approx}19{\pm}1.4\, \rm sec^{-1}Å^{-1}$, and the measured count is ${\approx}23{\pm}0.4\, \rm sec^{-1}Å^{-1}$. The reasonable agreement between the expected and observed values for Sirius-A in this initial consistency check after two years of observations with VELC, indicates that measurements of coronal brightness at 5303Å with the VELC and its conversion into absolute physical units using observations of the Sun disk light are in order. Using the Sirius-A observations we measured the point spread function (PSF) of the VELC in its 5303Å channel also. Its full width at half maximum (FWHM) is ${\approx}3.8^{\prime\prime}$.

2606.09247 2026-06-09 astro-ph.HE nucl-th 新提交

Bayesian analysis of the shear modulus in the neutron-star crust

中子星壳层剪切模量的贝叶斯分析

T. Diverrès, G. Montefusco, A. F. Fantina, F. Gulminelli

AI总结 通过贝叶斯分析评估中子星壳层剪切模量和剪切速度的不确定性,采用无信息先验和核物理信息先验,发现核物理先验显著降低预测不确定性,基频扭振模式频率与观测准周期振荡低频范围一致。

Comments 15 pages, 5 figures. Submitted to Astronomy & Astrophysics

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AI中文摘要

中子星壳层的弹性质对于壳层模式的计算至关重要。特别是,壳层支撑剪切应力的能力与准周期振荡的观测以及可能发射引力波的壳层形变有关。在这项工作中,我们评估了中子星外壳和内壳中剪切模量和剪切速度的不确定性。为此,我们从无信息先验和核物理信息先验出发,对零温度下中子星壳层的剪切性质进行了贝叶斯分析。对于壳层中非均匀物质的处理,我们依赖于单组分等离子体近似,并对离子进行(半)经典处理。我们表明,使用核物理信息先验对壳层弹性质的预测具有不可忽视的影响。我们获得的基频扭振壳层模式的频率与观测到的准周期振荡的低频范围兼容,我们的估计位于约20-50 Hz区间。尽管不同的先验导致兼容的结果,但在先验中包含核物理实验信息显著降低了壳层弹性质预测的不确定性,可能约束壳层模式的预测频率。

英文摘要

The elastic properties of the neutron-star crust are important for the calculations of crustal modes. In particular, the ability of the crust to support shear stresses has been connected to observations of quasi-periodic oscillations and to crust deformations potentially emitting gravitational waves. In this work, we assess the uncertainties in the shear modulus and shear speed in the neutron-star outer and inner crust. To this aim, we performed a Bayesian analysis of the shear properties of the neutron-star crust at zero temperature starting from both a non-informative and a nuclear-physics-informed prior. For the treatment of inhomogeneous matter in the crust, we relied on the one-component plasma approximation, with a (semi-)classical treatment of the ions. We show that the use of a nuclear-physics-informed prior has a non-negligible impact on the prediction of the elastic properties of the crust. The frequency of the fundamental torsional crustal modes we obtain is compatible with the low-frequency range of observed quasi-periodic oscillations, our estimates lying in the interval $\approx 20 - 50$~Hz. Although the different considered priors lead to compatible results, the inclusion of nuclear-physics experimental information in the prior considerably reduces the uncertainties in the prediction of the elastic properties of the crust, potentially constraining the predicted frequency of the crustal modes.

2606.09244 2026-06-09 cond-mat.mes-hall 新提交

Correlation enhanced resistance hysteresis near half filling in MoS2/WSe2 heterobilayer

MoS2/WSe2异质双层中半填充附近关联增强的电阻滞回

Yong Chen, Weikang Zhang, Meizhen Huang, Shengling Xiang, Zishu Zhou, Yaqi Ma, Chenxuan Lou, Haoxi Ji, Aoqian Zhang, Yifei Jin, Liheng An, Zefei Wu, Chun Cheng, Ning Wang

AI总结 在MoS2/WSe2莫尔超晶格器件中,通过电输运测量发现半填充附近存在关联绝缘态和显著的电阻滞回,其随温度和位移场变化证实了关联增强特性,归因于位移场诱导的金属-绝缘体转变与界面偶极的耦合。

Comments accepted in Chinese Physics Letters

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AI中文摘要

铁电性通常源于非中心对称晶格中的离子位移,使其在存储器件和传感器中具有应用潜力。二维材料和范德华异质结构的最新进展揭示了莫尔超晶格中的新型铁电现象,包括滑动铁电性和关联驱动铁电性。在本工作中,我们制备并研究了一种MoS2/WSe2莫尔超晶格器件,其具有高达17,650 $cm^2V^{-1}s^{-1}$的场效应迁移率。电输运测量显示,在半填充附近存在关联绝缘态,并伴有显著且可重复的电阻滞回。温度和位移场依赖性进一步证实了滞回的关联增强性质。我们的分析表明,位移场诱导的关联绝缘态处的金属-绝缘体转变与界面偶极的耦合导致了所观察到的电阻滞回。这些结果确立了MoS2/WSe2异质双层中半填充附近关联增强的电阻滞回,为探索新兴量子相和器件功能提供了机会。

英文摘要

Ferroelectricity, typically arising from ionic displacements in noncentrosymmetric lattices, enabling applications in memory devices and sensors. Recent advances in two-dimensional materials and van der Waals heterostructures have revealed novel ferroelectric phenomena, including sliding ferroelectricity and correlation-driven ferroelectricity in moire superlattices. In this work, we fabricate and study a MoS2/WSe2 moire superlattice device exhibiting a high field-effect mobility of 17,650 $cm^2V^{-1}s^{-1}$. Electrical transport measurements reveal correlated insulating states accompanied by a prominent and reproducible resistance hysteresis near half filling. Temperature and displacement field dependence further confirms the correlation-enhanced nature of the hysteresis. Our analysis suggests that displacement field-induced metal-to-insulator transition at correlated insulating state coupled with interfacial dipoles enables the observed resistance hysteresis. These results establish correlation enhanced resistance hysteresis near half filling in a MoS2/WSe2 heterobilayer, offering opportunities for exploring emergent quantum phases and device functionalities.

2606.09242 2026-06-09 cs.HC 新提交

Conceptualising Reflective Use: Toward A Process Perspective On Human-AI Interaction

概念化反思性使用:走向人机交互的过程视角

Thimo Schulz, Christina Speck

AI总结 提出反思性使用概念,涵盖使用前、中、后三阶段的认知行为能力,基于专家访谈和焦点小组识别四个核心组件,形成迭代能力循环,促进负责任的人机交互。

Comments 8 pages, 2 figures, 1 table, published in ECIS 2026 Proceedings

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AI中文摘要

生成式人工智能系统的快速扩散重塑了个人与信息系统的互动方式,要求用户监控、评估和调整与非确定性系统的交互。现有构念捕捉了这种互动的某些要素,但未能考虑生成式人工智能使用中整个评估过程的情境动态。这项正在进行的研究,作为更大规模量表开发工作的一部分,提出了反思性使用的初步概念化:一种行为-知识能力,跨越使用前、使用中和使用后阶段,并通过实践中获得的情境反思知识得到强化。基于专家访谈和焦点小组,我们识别出反思性使用的四个核心组件,并展示它们如何形成一个迭代的能力循环,该循环植根于自我决定理论所概述的动机需求。理解反思性使用对于确保适当的依赖和高决策质量至关重要,从而为促进负责任且有效的人机交互奠定基础。

英文摘要

The rapid diffusion of generative artificial intelligence (genAI) systems reshapes how individuals engage with information systems, requiring users to monitor, assess, and adapt their interaction with non-deterministic systems. Existing constructs capture elements of this engagement but do not account for the situated dynamics of the entire evaluative process in genAI use. This research-in-progress, situated in a larger endeavour towards a scale development, derives an initial conceptualisation of reflective use: a behavioural-knowledge capability that unfolds across pre-use, in-use, and post-use phases, reinforced through situated reflective knowledge gained in practice. Drawing on expert interviews and a focus group, we identify four core components of reflective use and show how they form an iterative capability cycle anchored within the motivational needs outlined in self-determination theory. Understanding reflective use is essential to ensure appropriate reliance and high decision quality, and thus provides a foundation for promoting responsible and effective human-AI interaction.

2606.09240 2026-06-09 gr-qc 新提交

Geodesic structure of the cosmological Levi-Civita spacetimes

宇宙学Levi-Civita时空的测地线结构

Adam Tyc, Martin Zofka

AI总结 研究具有非零宇宙学常数的静态柱对称时空中测地线的行为,利用对称性限制度量参数范围并解释坐标。

Comments This is the version of the article before peer review or editing, as submitted by an author to Classical and Quantum Gravity. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at 10.1088/1361-6382/ae68d1. 18 pages, 10 figures, 5 tables

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Journal ref
Class. Quantum Grav. 43 105010 (2026)
AI中文摘要

我们研究了在具有非零宇宙学常数的静态、柱对称时空中测地线行为的意义。我们考虑这些时空的对称性,以限制度量参数的允许范围,并形成对坐标的直观合理的解释。

英文摘要

We investigate the implications of the behavior of geodesics in static, cylindrically symmetric spacetimes with a non-zero cosmological constant. We consider the symmetries of these spacetimes to restrict admissible ranges of the metric parameters and to formulate an intuitively plausible interpretation of the coordinates.

2606.09238 2026-06-09 gr-qc astro-ph.IM 新提交

Detectability to extreme mass ratio inspirals with alternative space-based detector networks

替代空间探测器网络对极端质量比旋近的可探测性

Chao Zhang, Gang Wang

AI总结 研究LISA、天琴和两种太极轨道构型组成的探测器网络对EMRI的探测能力,发现联合观测可将源定位不确定性降低两个数量级,且三探测器网络一个月观测的参数约束可与LISA单独一年观测相当。

Comments 22 pages, 7 figures, 4 tables; comments are welcome

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AI中文摘要

极端质量比旋近(EMRI)是空间引力波(GW)探测器的主要目标之一,为研究绕超大质量黑洞(SMBH)运行的恒星质量致密天体以及探测强场引力提供了宝贵机会。由于LISA、太极和天琴任务预计在2035年左右运行,多个探测器的联合观测可能提供比单个任务更强的测量能力。本文研究了由LISA、天琴和两种替代太极轨道构型组成的全局探测器网络对EMRI的可探测性和参数约束前景。利用Fisher信息矩阵分析,我们发现联合观测相对于单独的LISA任务改善了源定位,对于一个月观测期,天区定位不确定性降低了多达两个数量级。我们进一步发现,运行一个月的三探测器网络(LISA-太极-天琴)产生的参数约束与LISA单独运行一年所获得的约束相当,在某些情况下甚至更紧。这一结果表明,网络观测可以在参数推断中部分补偿较短的观测持续时间。此外,我们评估了并发双信号场景下的测量不确定性:(i)两个EMRI绕同一SMBH运行,以及(ii)两个EMRI具有相同内在参数但不同天区位置和朝向。结果表明,与源几何相关的探测器响应差异降低了重叠信号之间的相关性,使得即使在单独任务中源也能保持可区分。在这些并发源场景中,多个探测器星座的加入进一步改善了源定位并收紧了参数约束。

英文摘要

Extreme mass ratio inspirals (EMRIs) are among the primary targets for space-based gravitational-wave (GW) detectors, providing valuable opportunities to study stellar-mass compact objects orbiting supermassive black holes (SMBHs) and to probe gravity in the strong-field regime. As the LISA, TAIJI, and TianQin missions are expected to operate around 2035, joint observations by multiple detectors may provide enhanced measurement capabilities compared to individual missions. In this work, we investigate the detectability and parameter-constraint prospects for EMRIs using global detector networks composed of LISA, TianQin, and two alternative TAIJI orbital configurations. Employing Fisher information matrix analysis, we find that joint observations improve source localization relative to a standalone LISA mission, with sky-localization uncertainties reduced by up to two orders of magnitude for a one-month observation period. We further find that a three-detector network (LISA-TAIJI-TianQin) operating for one month yields parameter constraints comparable to, and in some cases tighter than, those obtained from a one-year observation by LISA alone. This result indicates that network observations can partially compensate for shorter observation durations in parameter inference. Furthermore, we evaluate measurement uncertainties in concurrent dual-signal scenarios: (i) two EMRIs orbiting the same SMBH and (ii) two EMRIs with identical intrinsic parameters but different sky locations and orientations. The results indicate that differences in the detector responses associated with the source geometries reduce correlations between overlapping signals, allowing the sources to remain distinguishable even for a standalone mission. The inclusion of multiple detector constellations further improves source localization and tightens parameter constraints in these concurrent-source scenarios.

2606.09235 2026-06-09 math.DG math.AG 新提交

Semistability and asymptotics of geometric flows

几何流的半稳定性与渐近行为

Shing Tak Lam

AI总结 本文证明在斜率半稳定全纯向量丛上,Hermitian-Yang-Mills流的渐近行为由Haiden-Katzarkov-Kontsevich-Pandit迭代滤过代数几何地决定,并推广到Calabi流和矩映射流,将无限维流简化为有限维流。

Comments 39 pages, comments welcome

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AI中文摘要

我们证明,在紧Kähler流形上的斜率半稳定全纯向量丛上,Hermitian-Yang-Mills流的渐近行为由Haiden-Katzarkov-Kontsevich-Pandit定义的迭代滤过代数几何地决定。这证明了Haiden-Katzarkov-Kontsevich-Pandit在此设定下的一个猜想。此外,我们证明了一个非线性类比,将cscK流形附近的Calabi流的渐近行为与形变空间的迭代平衡滤过联系起来。在这两种设定中,我们遵循Chen-Sun的基础工作,将无限维流简化为有限维流。在有限维中,我们证明矩映射流的渐近行为由迭代平衡滤过决定,证明了Ibáñez Núñez的一个猜想。

英文摘要

We prove that the asymptotics of the Hermitian-Yang-Mills flow on a slope semistable holomorphic vector bundle over a compact Kähler manifold are determined algebro-geometrically, via the iterated filtration defined by Haiden-Katzarkov-Kontsevich-Pandit. This proves a conjecture of Haiden-Katzarkov-Kontsevich-Pandit in this setting. Moreover, we prove a non-linear analogue, relating the asymptotics of the Calabi flow near a cscK manifold to the iterated balancing filtration of the deformation space. In both settings, we reduce the infinite-dimensional flow to a finite-dimensional flow, following the foundational work of Chen-Sun. In finite dimensions, we prove that the asymptotics of the moment map flow are determined by the iterated balancing filtration, proving a conjecture of Ibáñez Núñez.

2606.09233 2026-06-09 physics.med-ph physics.app-ph 新提交

Slice-Profile-Enabled Phase Distribution Graphs for MRI Simulation

用于MRI模拟的切片轮廓使能的相位分布图

Snawar Hussain, Daniel C. Hoinkiss, Jörn Huber, Vincent Kuhlen, Matthias Günther

AI总结 提出一种统一的Bloch分辨PDG框架,通过将RF脉冲的切片轮廓效应编码为PDG状态图中的稀疏交叉阶耦合,实现切片轮廓感知的MRI模拟,在保持少量状态的同时与直接Bloch模拟高度一致。

Comments 10 pages, 8 figures, Preprint version

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AI中文摘要

MRI模拟通常将两种对真实序列分析都至关重要的描述分开:用于波形分辨射频(RF)激发的Bloch动力学,以及用于相干路径演化的相位图方法。扩展相位图(EPG)模型提供路径跟踪,而相位分布图(PDG)将此思想扩展到空间分辨的$k$-空间模拟,但现有的PDG公式依赖于硬脉冲RF混合,这是\textem{阶局部的}:RF脉冲在固定相干阶$n$处混合$F_n^+$、$F_n^-$和$Z_n$,而不耦合不同的$k_z$阶。本文引入了一个统一的Bloch分辨PDG框架,用于切片轮廓感知的MRI模拟。将扫描仪光栅化序列划分为对RF敏感的Bloch跨度段和非RF的相位图跨度段。对于每个唯一的RF跨度,在切片网格上求解Bloch动力学以获得空间变化的传播子$R(z)$。其傅里叶系数$\mathcal{R}_Δ$(由切片阶偏移$Δ$索引)被编译到PDG状态图中,作为$k_z$中的稀疏交叉阶耦合。通过保留主导傅里叶系数并剪枝低贡献PDG状态来控制图增长。这保留了PDG路径历史和体素级图像形成,同时结合了成形切片选择性和偏共振RF行为。实验表明,在重复激发下,与直接一维Bloch切片轮廓演化高度一致,同时仅保留几百个活跃PDG状态。图像模拟进一步展示了切片位置依赖性、脂肪抑制行为、测量的三维$B_0$场图以及与扫描仪数据的比较。所提出的框架能够在RF物理、空间编码、对象异质性和回波路径形成相互作用的场景中实现序列一致的模拟和信号形成理解。

英文摘要

MRI simulation often separates two descriptions that are both essential for realistic sequence analysis: Bloch dynamics for waveform-resolved radiofrequency (RF) excitation, and phase-graph methods for coherence-pathway evolution. Extended Phase Graph (EPG) models provide pathway tracking, and Phase--Distribution Graphs (PDG) extend this idea to spatially resolved $k$-space simulation, but existing PDG formulations rely on hard-pulse RF mixing that is \emph{order-local}: the RF pulse mixes $F_n^+$, $F_n^-$, and $Z_n$ at a fixed coherence order $n$, without coupling different $k_z$ orders. This work introduces a unified Bloch-resolved PDG framework for slice-profile-aware MRI simulation. A scanner-rasterized sequence is partitioned into RF-sensitive Bloch spans and non-RF phase-graph spans. For each unique RF span, Bloch dynamics are solved on a slice grid to obtain a spatially varying propagator $R(z)$. Its Fourier coefficients $\mathcal{R}_Δ$, indexed by slice-order offset $Δ$, are compiled into the PDG state graph as sparse cross-order coupling in $k_z$. Graph growth is controlled by retaining the dominant Fourier coefficients and pruning low-contribution PDG states. This retains PDG pathway history and voxel-wise image formation while incorporating shaped slice-selective and off-resonant RF behavior. Experiments show close agreement with direct one-dimensional Bloch slice-profile evolution through repeated excitations, while retaining only a few hundred active PDG states. Image simulations further illustrate slice-position dependence, fat-suppression behavior, measured three-dimensional $B_0$ field maps, and comparison with scanner data. The proposed framework enables sequence-consistent simulation and signal formation understanding in regimes where RF physics, spatial encoding, object heterogeneity, and echo-pathway formation interact.

2606.09232 2026-06-09 cond-mat.mes-hall 新提交

Strain-Induced Tuning of Third-Harmonic Generation in Monolayer Black Phosphorene

单层黑磷烯中应变诱导的三次谐波产生调谐

Yan Meng, Kainan Chang, Wei Song, Yuwei Shan, Jin Luo Cheng, Luxia Wang

AI总结 基于紧束缚模型和半导体布洛赫方程,揭示了应变工程调控单层黑磷烯三次谐波产生的微观机制,发现面内压缩和面外拉伸应变增强THG并导致红移,而面内拉伸和面外压缩则抑制THG并导致蓝移,调谐效率遵循z>y>x顺序。

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AI中文摘要

基于紧束缚模型和半导体布洛赫方程,本工作系统地揭示了应变工程调控单层黑磷烯(BP)中三次谐波产生(THG)的微观机制。结果表明,在无应变条件下,单层BP表现出显著的面内各向异性,其主导的磁化率分量达到最大值$χ^{(3);xxxx} = 1.8 \times 10^{-17} \, \text{m}^2/\text{V}^2$,与实验结果吻合良好。通过沿扶手椅($x$)、锯齿形($y$)和面外($z$)方向施加单轴和双轴应变,我们发现THG响应表现出强烈的方向依赖性和独特的光谱移动行为:面内压缩应变和面外拉伸应变均显著增强THG电导率并导致红移,而面内拉伸应变和面外压缩则导致抑制和蓝移,调谐效率遵循$z > y > x$的顺序。这些现象的微观起源被识别为应变对带隙和贝里连接的协同调制。此外,双轴应变的协同或竞争效应进一步丰富了THG信号的操控。应变工程可作为动态控制二维材料中非线性光学过程的有效策略,也为开发高性能可重构红外光子器件奠定了理论基础。

英文摘要

Based on the tight-binding model and the semiconductor Bloch equations, this work systematically reveals the microscopic mechanism of strain engineering in turning of third-harmonic generation (THG) in monolayer black phosphorene (BP). % The results show that under strain-free conditions, monolayer BP exhibits significant in-plane anisotropy, and its dominant susceptibility component reaches a maximum of $χ^{(3);xxxx} = 1.8 \times 10^{-17} \, \text{m}^2/\text{V}^2$, agreeing well with the experimental results. % By applying uniaxial and biaxial strains along the armchair ($x$), zigzag ($y$), and out-of-plane ($z$) directions, we find that the THG response presents strong direction dependence and unique spectral shifting behaviors: in-plane compressive strain and out-of-plane tensile strain both significantly enhance the THG conductivity and induce a redshift, whereas in-plane tensile strain and out-of-plane compression lead to suppression and a blueshift, with the tuning efficiency following the order of $z > y > x$. The microscopic origin of these phenomena is identified as the synergistic modulation of the bandgap and Berry connection by strain. % Furthermore, the synergistic or competitive effects of biaxial strain further enrich the manipulation of THG signals. % Strain engineering can serve as an effective strategy for dynamically controlling nonlinear optical processes in two-dimensional materials, and it also lays a theoretical foundation for the development of high-performance reconfigurable infrared photonic devices.

2606.09231 2026-06-09 math.CO 新提交

Constrained homomorphism orders

约束同态序

Jiri Fiala, Jan Hubicka, Yangjing Long

AI总结 研究有限图约束同态(如单同态、嵌入、满同态等)诱导的偏序,分析其核心、有限性、对偶性等结构性质,并统一框架。

Comments arXiv admin note: text overlap with arXiv:1404.5334

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AI中文摘要

我们研究由有限图同态的约束变体诱导的偏序:单同态、嵌入、全同态、顶点满射、边满射和满射同态,以及局部单射、局部满射和局部双射同态。对于每个序,我们寻求图同态序的标准结构性质的类比:典范核、过去或未来有限性、普适性、间隙和有限对偶性。比较表明哪些现象是普通同态特有的,哪些是更简单的序理论机制的后果。我们为全同态和满射同态识别核,将全同态核与点确定图联系起来,刻画全同态序中的间隙,并给出几个单边有限序的有限障碍界。我们还分析了连通图上的局部约束同态。特别地,局部单射同态将所有连通图作为核,在自然度细化假设下允许无限链密度,具有显式间隙见证,并且已经在有限连通二分次三次仙人掌图上具有普适性。本文重新组织并扩展了若干早期论证,为约束同态序建立了一个统一框架。

英文摘要

We study partial orders induced by constrained variants of finite graph homomorphisms: monomorphisms, embeddings, full homomorphisms, vertex-surjective, edge-surjective and surjective homomorphisms, and locally injective, locally surjective and locally bijective homomorphisms. For each order we ask for analogues of the standard structural properties of the graph homomorphism order: canonical cores, past- or future-finiteness, universality, gaps and finite dualities. The comparison shows which phenomena are specific to ordinary homomorphisms and which are consequences of simpler order-theoretic mechanisms. We identify cores for full and surjective homomorphisms, relate full-homomorphism cores to point-determining graphs, characterize gaps in the full homomorphism order, and give finite obstruction bounds for several one-sided finite orders. We also analyze locally constrained homomorphisms on connected graphs. In particular, locally injective homomorphisms have all connected graphs as cores, admit infinite-chain density under natural degree-refinement assumptions, have explicit gap witnesses, and are universal already on finite connected bipartite subcubic cactus graphs. The paper reorganizes and extends several earlier arguments into a single framework for constrained homomorphism orders.

2606.09229 2026-06-09 astro-ph.HE 新提交

GRB 250706B/C: Insight-HXMT Discovery of a High-Luminosity Burst as a Candidate for Fallback-Regulated Accretion in the Prompt Emission

GRB 250706B/C: Insight-HXMT发现的一个高光度暴,作为瞬时辐射中回落调节吸积的候选体

Chen-Wei Wang, R. Moradi, Shao-Lin Xiong, Shuang-Nan Zhang, Zheng-Hang Yu, Wen-Jun Tan, Hao-Xuan Guo, Xiao-Bo Li, Cheng-Kui Li, Jia-Cong Liu, Xing-Hao Luo, Yang-Zhao Ren, Yue Wang, Sheng-Lun Xie, Wang-Chen Xue, Yuan-Zao Xue, Peng Zhang, Chao Zheng

AI总结 基于Insight-HXMT观测到的长暴GRB 250706B/C,发现其瞬时辐射同时具有极短时标变化和缓慢演化的包络,支持回落吸积盘在高光度分支工作的模型。

Comments Accepted for publication in The Astrophysical Journal Letters

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AI中文摘要

坍缩星模型中的回落吸积通常与低光度伽马射线暴(GRB)相关,导致普遍观点认为回落供能的引擎本质上难以产生高光度事件。本文中,我们介绍由\textit{Insight}-HXMT观测到的明亮长暴GRB 250706B/C,它展现出极短时标变化和相干大尺度时间演化的不寻常组合。瞬时辐射包含至少79个分辨脉冲,最小变时标约为11毫秒。脉冲宽度几乎与光子能量无关,分布广泛,中值半高全宽约为0.30秒,而相邻脉冲之间的等待时间中值约为0.38秒。瞬时辐射包络呈现持续上升,由$F(t)\propto (t-t_0)^{0.47\pm0.01}$描述,随后快速下降。尽管脉冲间存在显著涨落,但在主辐射阶段,脉冲宽度和等待时间均未表现出显著的长期演化。这些特征表明两种不同时间成分共存:缓慢演化的上升光度包络和快速随机变率。这种行为与以下情景一致:时变的引擎供能历史调控大尺度辐射,而相对论性出流内的内部耗散产生脉冲结构。在此背景下,GRB 250706B/C可能代表一个在高光度分支上运行的回落供能坍缩星,表明回落本身并不必然限制GRB的光度尺度。

英文摘要

Fallback accretion in collapsar models is often associated with underluminous gamma-ray bursts (GRBs), leading to the widespread view that fallback-fed engines may be intrinsically inefficient at producing high-luminosity events. In this Letter, we present GRB 250706B/C, a luminous long GRB observed by \textit{Insight}-HXMT that exhibits an unusual combination of extreme short-timescale variability and coherent large-scale temporal evolution. The prompt emission contains at least 79 resolved pulses and a minimum variability timescale of $\sim11$ ms. The pulse widths are nearly independent of photon energy and span a broad distribution with a median FWHM of $\sim0.30$ s, while the waiting times between adjacent pulses have a median of $\sim0.38$ s. The prompt-emission envelope exhibits a prolonged rise described by $F(t)\propto (t-t_0)^{0.47\pm0.01}$ followed by a rapid decline. Despite substantial pulse-to-pulse fluctuations, neither the pulse widths nor the waiting times show significant secular evolution during the main emission episode. These features indicate the coexistence of two distinct temporal components, including a slow evolving rising luminosity envelope and rapid stochastic variability. Such behavior is consistent with scenarios in which a time-dependent engine-feeding history regulates the large-scale emission while internal dissipation within the relativistic outflow produces the pulse structure. Within this context, GRB~250706B/C may represent a fallback-fed collapsar operating on a high-luminosity branch, suggesting that fallback itself does not necessarily limit the luminosity scale of GRBs.

2606.09228 2026-06-09 math.PR 新提交

On topological indices of random caterpillar graphs

随机毛毛虫图的拓扑指数

Florian Lesny, Ralph Neininger, Markus Schmieder

AI总结 基于多元中心极限定理、连续映射定理和Slutsky定理,研究随机毛毛虫图随规模增长时Zagreb、α-Randić、Wiener、Gini和level指数的渐近行为,推导极限分布及均值和方差的精确与渐近结果。

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AI中文摘要

我们考虑随机毛毛虫图的拓扑指数的渐近行为,例如Zagreb、$α$-Randi\'c、Wiener、Gini和level指数,随着图的大小增长。我们的简单通用框架基于多元中心极限定理、连续映射定理和Slutsky定理,也可用于覆盖其他拓扑指数。我们推导了这些指数的极限定律,并给出了其均值和方差的精确与渐近结果。$α$-Randi\'c指数在$α=\frac{1}{2}$处表现出极限分布的不连续性。

英文摘要

We consider the asymptotic behaviour of topological indices of random caterpillar graphs, such as the Zagreb, $α$-Randić, Wiener, Gini and level indices, as the size of the graph grows. Our simple, general framework, which is based on a multivariate central limit theorem, the continuous mapping theorem and Slutsky's theorem, can also be used to cover other topological indices. We derive limit laws for these indices and provide exact and asymptotic results on their means and variances. The $α$-Randić index exhibits a discontinuity in its limit distribution at $α=\frac{1}{2}$.

2606.09226 2026-06-09 astro-ph.SR 新提交

Predictability of a solar flare in May 2024 using observational data-driven MHD simulations

2024年5月太阳耀斑的可预测性:基于观测数据驱动的MHD模拟

Takafumi Kaneko

AI总结 利用观测数据驱动的磁流体动力学模拟,研究了2024年5月3日X1.6级耀斑的可预测性,发现通过结合最终时刻的光球速度场可延长预测提前量至1小时以上。

Comments 33 pages, 14 figures, accepted for publication in Earth, Planets, and Space

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AI中文摘要

我们检验了观测数据驱动的磁流体动力学(MHD)模拟在耀斑预测中的适用性。目标事件是2024年5月3日02:22 UT在NOAA AR 13663发生的X1.6级耀斑。我们采用速度驱动模型,其中光球速度场从时间序列磁图中导出,用作边界输入。模拟显示,在X1.6耀斑实际爆发时间和位置附近,热能和动能密度迅速增加。我们发现该耀斑由两步重联触发:初始的系绳切割重联促进了随后的爆发重联。我们进一步检验了当边界输入在实际耀斑爆发时间之前停止时(假设必须使用实际发生前的数据进行预测的情况),耀斑是否能够被重现。当光球磁场在实际耀斑爆发时间前1小时以上固定时,模拟中未重现耀斑。相反,当结合最终观测时刻的光球速度场来推断后续磁场演化时,预测提前量可延长至1小时以上。另一方面,耀斑强度的定量预测仍是未来研究的课题。

英文摘要

We examined the applicability of observational data-driven magnetohydrodynamic (MHD) simulations to flare prediction. The target event was the X1.6 flare that occurred in NOAA AR 13663 at 02:22 UT on 3 May 2024. We employed a velocity-driven model, in which the photospheric velocity field was derived from the time-series magnetograms to use as the boundary input. The simulation showed a rapid increase in both thermal and kinetic energy density around the actual onset time and location of the X1.6 flare. We revealed that the flare was triggered by two-step reconnection, in which the initial tether-cutting reconnection facilitated the subsequent breakout reconnection. We further examined whether the flare could be reproduced when the boundary input was stopped prior to the actual flare onset time, assuming the situation in which the flare must be predicted using the data before it actually occurs. When the photospheric magnetic field was fixed more than 1 hour before the actual flare onset time, the flare was not reproduced in the simulations. In contrast, when the photospheric velocity field at the final observation time was incorporated to infer the subsequent magnetic evolution, the prediction lead time could be extended beyond 1 hour. On the other hand, quantitative prediction of the magnitude of flares remains a subject for future study.