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2605.20605 2026-05-21 physics.optics

Engineering Hybrid Resonances in Nanophotonics

在纳米光子学中工程混合共振

Shutao Zhang, Cheng-Feng Pan, Yandong Fan, Jehyeon Shin, Yuanda Liu, Yan Liu, Jun Ding, Jing Wu, Junsuk Rho, Yuri Kivshar, Joel K. W. Yang, Zhaogang Dong

AI总结 本文研究了通过结合等离子体共振和介电米氏共振来克服单一系统限制,提升纳米光子学功能和应用的混合共振设计方法,并探讨了其在不同应用领域中的性能。

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AI中文摘要

共振的混合化已知可以克服单个系统的固有限制,从而实现先进的功能和应用。本文讨论了最近出现的混合等离子体-米氏谐振器,这些谐振器通过协同结合等离子体组件的强近场增强与介电米氏元件的低损耗、多极共振,成为推进纳米光子学结构的重要方向。我们回顾了该领域的最新进展,涵盖基本物理原理、结构设计策略、材料平台、计算优化方法以及代表性器件实现。我们的讨论首先评估了等离子体和米氏共振的互补特性,随后描述了这些共振之间的耦合,以增强光-物质相互作用。之后,我们探讨了高效混合谐振器在不同应用领域中的性能。除了传统的金属-介电系统外,我们还考虑了最近出现的介电接近零(ENZ)材料,这些材料可以在零介电常数附近提供独特的场局域、相位工程和能量流管理优势,为设计混合纳米光学器件提供了更大的灵活性。最后,我们指出了改进功能和高效纳米光子器件的潜在研究方向,特别是涉及新兴拓扑材料系统,如Sb2Te3、Bi2Te3、Bi2Se3,结合等离子体放大、介电约束和自旋依赖光学行为。

英文摘要

Hybridization of resonances is known to overcome inherent limitations of individual systems, enabling advanced functionalities and applications. Here we discuss hybrid plasmonic-Mie resonators that emerged recently as a promising direction in advancing nanophotonic structures by synergistically combining the strong near-field enhancement of plasmonic components with the low-loss, multipolar resonances of dielectric Mie elements. We review the recent progress in the field, encompassing the fundamental physical principles, structural design strategies, material platforms, computational optimization approaches, and representative device implementations. Our discussion starts by evaluating the complementary characteristics of plasmonic and Mie resonances followed by a description of the coupling between these resonances in order to boost light-matter interactions. Afterward, we explore the performance of efficient hybrid resonators for different application areas. Apart from the conventional metal-dielectric systems, we consider the recent class of epsilon-near-zero (ENZ) materials, which can provide unique advantages in terms of field localization, phase engineering, and energy flow management in the vicinity of zero-permittivity conditions, offering more flexibility in designing hybrid nano-optical devices. Lastly, we point out potential research avenues aiming to improve functional and efficient nanophotonic devices, especially those involving emerging topological material systems, such as Sb2Te3, Bi2Te3, Bi2Se3, combining plasmonic amplification, dielectric confinement, and spin-dependent optical behavior.

2605.20604 2026-05-21 stat.ME

Conditional regularized halfspace depth for sparse functional data and its applications

基于稀疏函数数据的条件正则化半空间深度及其应用

Hyemin Yeon, Xiongtao Dai, Sara Lopez-Pintado

AI总结 本文提出了一种新的稀疏函数数据深度概念——条件正则化半空间深度(CRHD),用于评估稀疏观测数据的深度,克服了现有方法对重构曲线的依赖,并通过排名检验和婴儿生长数据集展示了其应用价值。

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AI中文摘要

许多函数数据集是稀疏且不规则观测的。对这类数据进行排序具有挑战性,因为每个观测点仅提供有限的信息,而潜在轨迹仍然是无限维的。本文开发了一种新的深度概念,称为条件正则化半空间深度(CRHD)。CRHD定义为给定观测稀疏测量的潜在轨迹的条件半空间概率的下确界,从而允许在稀疏观测上直接进行深度评估,而不需要轨迹重构。我们研究了CRHD的几个基本理论性质,以澄清其作为深度度量的行为。所提出的深度甚至适用于极其稀疏观测的函数数据,克服了现有稀疏函数深度方法的关键限制,这些方法通常依赖于重构曲线。此外,CRHD为复杂函数数据诱导了有意义的排名。通过基于排名的检验展示了其数值性能,并通过婴儿生长数据集展示了其实际应用价值。

英文摘要

Many functional datasets are observed sparsely and irregularly. Ordering such data is challenging because only limited information is available from each observation, while the underlying trajectories remain infinite-dimensional. This paper develops a novel depth notion for sparse functional data, called the conditional regularized halfspace depth (CRHD). CRHD is defined as the infimum of conditional halfspace probabilities of the underlying trajectory given the observed sparse measurements, thereby enabling depth evaluation directly at sparse observations without requiring trajectory reconstruction. We study several basic theoretical properties of CRHD that clarify its behavior as a depth measure. The proposed depth is applicable even to extremely sparsely observed functional data, overcoming key limitations of existing sparse functional depths that often rely on reconstructed curves. In addition, CRHD induces meaningful rankings for complex functional data. Its numerical performance is demonstrated through rank-based tests, and its practical utility is illustrated using an infant growth dataset.

2605.20603 2026-05-21 math.AC math.CO

Critical subgraphs and the regularity of symbolic powers of cover ideals of graphs

临界子图与图的覆盖理想符号幂的正则性

Nguyen Thu Hang, Thanh Vu

AI总结 本文通过t-可接受子图确定图的覆盖理想t次符号幂的正则性,并应用于双部单环图的覆盖理想幂的正则性计算。

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AI中文摘要

设G为一个简单图。我们展示了一种利用G的t-可接受子图来确定G的覆盖理想t次符号幂的正则性的方法。作为应用,我们计算了双部单环图的覆盖理想幂的正则性。

英文摘要

Let $G$ be a simple graph. We demonstrate a method for using $t$-admissible subgraphs of $G$ to determine the regularity of the $t$-th symbolic power of the cover ideal of $G$. As an application, we compute the regularity of powers of cover ideals of bipartite unicyclic graphs.

2605.20601 2026-05-21 econ.EM

Endogenous Quantile Regression with Measurement Error in Dependent Variable

内生分位数回归与因变量测量误差

Xuanjing Su

AI总结 本文研究了存在内生解释变量和因变量测量误差的分位数回归问题,提出了一种两步筛分最大似然估计方法,通过控制函数方法证明了条件分位数系数函数及其他分布参数非参数可识别性,并通过蒙特卡洛模拟验证了该方法在存在内生性和加性测量误差时的有效性。

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AI中文摘要

本文研究了存在内生解释变量和因变量测量误差的分位数回归问题。标准分位数回归估计量忽视这两个要素会引入显著偏误。本文在三角系统中采用控制函数方法,证明条件分位数系数函数及其他分布参数非参数可识别。基于这一识别结果,本文提出了一种两步筛分最大似然估计方法。第一步估计控制函数,第二步进行筛分似然最大化,通过皮尔逊权重整合生成的控制变量。当分位数网格节点数以适当速度增长时,估计量一致且渐近正态,允许通过自助法进行推断。蒙特卡洛模拟显示,该估计量相对于现有方法显著减少了偏误,证实了其在存在内生性和加性测量误差时的有效性。

英文摘要

This paper studies quantile regression with an endogenous regressor and measurement error in the dependent variable. Standard quantile regression estimators ignoring these two elements can induce substantial bias. We adopt a control-function approach in a triangular system and show that the conditional quantile coefficient functions, together with all other distributional parameters, are nonparametrically identifiable. Building on this constructive identification result, we propose a two-step sieve ML estimator. The first step estimates the control function. The second step performs a sieve likelihood maximization that incorporates the generated control variable through copula weights. When the number of quantile grid knots grows at an appropriate speed, the estimator is consistent and asymptotically normal, permitting inference via bootstrap. Monte Carlo simulations demonstrate that the estimator markedly reduces bias relative to existing methods, confirming its effectiveness in settings with endogeneity and additive measurement error in the outcome.

2605.20598 2026-05-21 math.AG math.AT math.NT

The pro-étale fundamental group of singular schemes

奇异方案的pro-étale基本群

Jiu-Kang Yu, Lei Zhang

AI总结 本文通过研究奇异方案的pro-étale基本群,结合其不可约分量的étale基本群和一个离散自由群,推广了E. Lavanda关于半稳定曲线的公式,并利用适当的降维技术与Noohi群的组合Van Kampen构造进行证明。

Comments With an appendix by Marcin Lara

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AI中文摘要

我们通过不可约分量的正常化étale基本群和一个离散自由群来计算连通的Nagata J-2方案的pro-étale基本群。该结果推广了E. Lavanda对半稳定曲线的公式,并依赖于对étale映射的适当降维技术与Noohi群的组合Van Kampen构造。作为副产品,我们还 characterize了pro-étale基本群的连续表示何时能通过离散商因子。

英文摘要

We compute the pro-étale fundamental group of a connected Nagata J-2 scheme in terms of the étale fundamental groups of the normalizations of its irreducible components and a discrete free group. The result generalizes a formula of E. Lavanda for semi-stable curves and relies on a combination of proper descent techniques for étale morphisms and a combinatorial van Kampen construction for Noohi groups. As a by-product we characterize when a continuous representation of the pro-étale fundamental group factors through a discrete quotient.

2605.20596 2026-05-21 astro-ph.HE

Binary Neutron Star Merger Evolution and r-Process Enrichment in the Milky Way Disk

双星中子星合并演化与银河系盘内r过程富集

Joon Young Lee, Hsin-Yu Chen, Muhammed Saleem

AI总结 研究通过分析引力波观测、伽马射线暴、银河系中子星人口及银河系盘星丰度测量,发现双星中子星合并的r过程富集效率随红移演化是解释银河系盘星r过程富集的关键因素,且与伽马射线暴观测存在矛盾,但符合引力波背景约束。

Comments Comments are welcome!

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AI中文摘要

半数快速中子捕获核合成(r过程)元素的起源仍是一个开放性问题。双星中子星(BNS)合并被证明在再现银河系盘星观测到的r过程富集方面存在困难。然而,其r过程富集效率可能随着红移变化而变化,这可能由于合并率或早期宇宙平均r过程产率的演化所致。本文探讨了BNS合并具有演化富集效率的可能性,作为唯一r过程生成通道。通过联合比较LIGO--Virgo--KAGRA引力波观测、短伽马射线暴、银河系中子星人口及银河系盘星丰度测量,发现具有额外演化的场景比非演化的场景更受青睐,贝叶斯因子超过10^20。我们量化了合并率和产率的所需演化,并将其与观测和理论预测进行直接比较。发现演化场景与短伽马射线暴观测和多个群体合成模型的预测存在矛盾,但与当前随机引力波背景约束一致。我们的结果为评估BNS合并具有演化富集效率是否能解释银河系盘星观测到的r过程富集历史提供了定量框架。

英文摘要

The origin of half of the rapid neutron-capture nucleosynthesis (r-process) elements in the Universe remains an open question. Binary neutron star (BNS) mergers have been shown to face difficulties in reproducing the observed r-process enrichment in Milky Way disk stars. However, their r-process enrichment efficiency may evolve with redshift beyond the star formation history, potentially due to evolution in the merger rate or the average r-process yield in the early Universe. In this paper, we explore the possibility that BNS mergers with an evolving enrichment efficiency could serve as the sole r-process production channel. By jointly comparing gravitational-wave observations from LIGO--Virgo--KAGRA, short gamma-ray bursts, Galactic neutron star populations, and stellar abundance measurements in Milky Way disk stars, we find that scenarios with additional evolution are strongly preferred over non-evolving scenarios, with Bayes factors exceeding $10^{20}$. We quantify the required evolution in both the merger rate and yield, and directly compare them with observations and theoretical predictions. We find that the evolved scenarios are in tension with short gamma-ray burst observations and predictions from multiple population synthesis models, while remaining consistent with current stochastic gravitational-wave background constraints. Our results provide a quantitative framework for evaluating whether BNS mergers with evolving enrichment efficiency can account for the observed r-process enrichment history of Milky Way disk stars.

2605.20594 2026-05-21 math.AG

An example of a very non-movable effective divisor

非常不可移动的有效除子的一个例子

Jihao Liu

AI总结 本文通过生成式AI技术,给出了关于光滑射影表面上正自相交有效除子问题的否定回答,反驳了Ciliberto等人提出的猜想。

Comments 4 pages. AI generated, human verified

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AI中文摘要

我们回答了Ciliberto、Knutsen、Lesieutre、Lozovanu、Miranda、Mustopa和Testa关于光滑射影表面上正自相交有效除子的问题的否定答案。本文的主要结果是通过生成式AI,特别是Chatgpt 5.5 pro和Rethlas系统获得的。

英文摘要

We give a negative answer to a question of Ciliberto, Knutsen, Lesieutre, Lozovanu, Miranda, Mustopa, and Testa on effective divisors of positive self-intersection on smooth projective surfaces. The main result of this paper is obtained by generative AI, particularly Chatgpt 5.5 pro and the Rethlas system.

2605.20593 2026-05-21 math.OC math.PR

Viscosity Solutions of Stochastic Hamilton--Jacobi--Bellman Equations with Jumps

具有跳跃的随机Hamilton-雅可比-贝尔曼方程的粘性解

Dunxiang Liang, Qingxin Meng

AI总结 本文研究了跳跃扩散过程的随机最优控制及相关的非线性反向随机Hamilton-雅可比-贝尔曼方程,通过反向半群建立动态规划原理以刻画价值函数,并引入基于半鞅测试函数和全局切线条件的随机粘性解框架来处理非局部积分微分算子和多项式增长问题,最后在超抛物性条件下建立弱比较原理并证明了全局唯一性。

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AI中文摘要

本文研究了跳跃扩散过程的随机最优控制及相关的非线性反向随机Hamilton-雅可比-贝尔曼方程。我们通过反向半群建立动态规划原理以刻画价值函数。为了处理非局部积分微分算子和多项式增长,我们引入基于半鞅测试函数和全局切线条件的随机粘性解框架。通过可测选择定理和广义Itô-Kunita公式证明了存在性。最后,在超抛物性条件下,我们建立了弱比较原理,并通过局部化上界和反向归纳证明了全局唯一性。

英文摘要

This paper studies the stochastic optimal control of jump-diffusion processes and the associated fully nonlinear backward stochastic Hamilton--Jacobi--Bellman (BSHJB) equations. We establish the dynamic programming principle (DPP) via backward semigroups to characterize the value function. To handle non-local integro-differential operators and polynomial growth, we introduce a stochastic viscosity solution framework based on semimartingale test functions and global tangency conditions. Existence is proved using the measurable selection theorem and the generalized Itô--Kunita formula. Finally, under a super-parabolicity condition, we establish a weak comparison principle and prove global uniqueness via localized bounding envelopes and backward induction.

2605.20590 2026-05-21 astro-ph.GA

Spider-Webb: enhanced star formation in low-mass galaxies within the Spiderweb protocluster revealed by JWST Pa$β$ narrow-band imaging

Spider-Webb:通过JWST Paβ窄带成像揭示Spiderweb原星团中低质量星系的增强恒星形成

Kazuki Daikuhara, Tadayuki Kodama, Yusei Koyama, Rhythm Shimakawa, Helmut Dannerbauer, Jose Manuel Pérez-Martínez, Pablo G. Pérez-González, Mariko Kubo, Eduardo Ibar, Philip N. Best, Abdurrahman Naufal, Yuheng Zhang, Ronaldo Laishram

AI总结 通过JWST Paβ窄带成像研究Spiderweb原星团中z=2.16处的星系恒星形成活动,发现低质量星系的恒星形成率增强,而中间和高質量星系则没有显著差异,揭示了环境对恒星形成的影响与质量相关。

Comments 16 pages, 5 figures, Accepted for publication in MNRAS

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AI中文摘要

理解环境在星系演化中的作用对于揭示调节星系增长的物理过程至关重要。我们利用詹姆斯·韦伯太空望远镜/NIRCam窄带成像研究了Spiderweb原星团(z=2.16)中Paβ发射体(PBEs)的恒星形成活动。为了研究恒星形成与环境的关系,我们从Paβ发射线推导出恒星形成率(SFRs),并将Spiderweb原星团中的SFRs与场星系进行比较。我们的主要发现是,原星团中的低质量PBEs(M* < 10^9 M☉)的恒星形成率比其场对应物有所增强。这种超额现象即使不应用尘埃消光修正也依然存在,表明原星团中的增强恒星形成率在是否应用尘埃修正时都具有鲁棒性。相比之下,中间质量和高质量PBEs(M* > 10^9 M☉)没有显著偏离场星系,揭示了环境对恒星形成影响的强质量依赖性。在原星团中没有观察到低质量恒星burst星系向原星团核心聚集的明显空间集中,这表明其增强不局限于原星团核心。我们建议低质量星系的恒星burst由环境过程如星系并合/相互作用,以及/或高效的气体供应所促进。尽管低质量端的增强与在相似红移处报道的其他原星团的趋势一致,但中间质量(10^9 < M* / M☉ < 10^10)的恒星形成行为在不同原星团中并不统一。我们的基于Paβ的结果表明,宇宙中午的恒星形成增强取决于质量和原星团的动态状态。

英文摘要

Understanding the role of the environment in galaxy evolution is key to revealing the physical processes that regulate galaxy growth. We study the star formation activity of \pab\ emitters (PBEs) in the Spiderweb protocluster at $z=2.16$ using \textit{James Webb Space Telescope}/NIRCam narrow-band imaging. To investigate the environmental dependence of star formation, we derive star formation rates (SFRs) from the \pab\ emission line and compare SFRs in the Spiderweb protocluster with those in the field. Our main finding is that low-mass PBEs ($M_\star < 10^9\,M_\odot$) in the Spiderweb protocluster exhibit an enhancement in star formation compared to their field counterparts. This excess persists even without applying dust-attenuation corrections, indicating that enhanced star formation in the protocluster is robust regardless of whether a dust correction is applied. In contrast, intermediate- and high-mass PBEs ($M_\star > 10^9\,M_\odot$) show no significant deviation from the field, revealing a strong mass dependence in the environmental effects on star formation. No clear spatial concentration toward the cluster core of starbursting low-mass galaxies within the protocluster is seen, suggesting that their enhancement is not restricted to the cluster core. We suggest that starbursts in low-mass galaxies are facilitated by environmental processes such as galaxy mergers/interactions, and/or efficient gas supply. While the enhancement at the low-mass end is consistent with trends reported for other protoclusters at similar redshifts, the behaviour of star formation at intermediate masses ($10^{9} < M_\star/M_\odot < 10^{10}$) is not uniform across protoclusters. Our \pab-based results in the Spiderweb protocluster indicate that star-formation enhancement at cosmic noon depends on both mass and the dynamical state of the protocluster.

2605.20587 2026-05-21 math.PR

Persistence and entropic repulsion of stationary Gaussian fields with spectral singularity at the origin

具有原点谱奇异性的平稳高斯场的持久性和熵排斥

Naomi Feldheim, Ohad Feldheim, Stephen Muirhead

AI总结 本文研究了具有原点谱奇异性的平稳高斯场的持久概率的精确对数渐近行为,并确定了在持久条件下熵排斥分布,该研究适用于一般d维平稳高斯场,结果依赖于参数α和d,并通过α-里斯核的容量和平衡势显式表达。

Comments 59 pages

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AI中文摘要

我们计算了具有原点谱奇异性的平稳高斯场的持久概率的精确对数渐近行为,并确定了在持久条件下熵排斥分布,适用于一般d维平稳高斯场,其中谱奇异性的阶数为α∈[0,d)。在温和的正则性条件下,这些结果被证明是通用的,仅依赖于α和d,并通过α-里斯核的容量和平衡势显式表达。这扩展了Bolthausen、Deuschel和Zeitouni关于高斯自由场的结果,应用于更广泛的具有谱奇异性的高斯场。

英文摘要

We compute the exact log-asymptotics of the persistence probability, and determine the entropic repulsion profile conditioned on persistence, for general $d$-dimensional stationary Gaussian fields with spectral singularity at the origin of order $α\in [0,d)$. Under mild regularity conditions these are shown to be universal, depending only on $α$ and $d$, and to have explicit formulations in terms of the capacity and equilibrium potential of the $α$-Riesz kernel. This generalises a result of Bolthausen, Deuschel and Zeitouni on the Gaussian free field to a wide class of Gaussian fields with spectral singularity.

2605.20586 2026-05-21 math.CT

Exponentiable Virtual Double Categories and Representability of Exponentials

可指数虚拟双范畴与指数的可表示性

Kevin D. Carlson, Ea E Thompson

AI总结 本文研究了虚拟双范畴的可指数性,通过细胞分解的存在性给出了等价刻画,并证明了余弦的虚拟双范畴、伪双范畴以及可指数多范畴的可指数性,同时给出了虚拟双范畴的虚拟双函子的复合条件。

Comments 112 pages

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AI中文摘要

虚拟双范畴提供了一个有效的框架用于形式范畴论。最近的研究探讨了虚拟双范畴之间的高阶态射问题,继双范畴之间的高阶态射研究之后,逐步发展到Arkor关于可指数虚拟双范畴的猜想——那些虚拟双范畴,其出射可以自身富集为整个虚拟双范畴。在本文中,我们通过提供若干等价刻画来解决Arkor的猜想,这些刻画基于细胞分解的存在性。我们还证明了余弦的虚拟双范畴总是可指数的,以及由伪双范畴或可指数多范畴产生的虚拟双范畴也是可指数的,如Pisani所研究的。我们还给出了在何种条件下虚拟双范畴的虚拟双函子允许复合,这基于Paré对于非虚拟情况的工作。我们的工作基于一个一般性的方法,用于对极限草图模型的范畴的可指数性,我们将此方法应用于给出半范畴、范畴、多范畴及其函子的可指数性的新处理。

英文摘要

Virtual double categories provide an effective framework for formal category theory. Recent work has investigated the question of higher morphisms between virtual double categories, following on from work on higher morphisms between double categories, and building up to Arkor's recent conjecture on exponentiable virtual double categories--those virtual double categories, morphisms out of which can themselves be enriched to a whole virtual double category. In this paper we resolve Arkor's conjecture by providing a number of equivalent characterizations of the exponentiable virtual double categories in terms of existence of decompositions of cells. We also show that virtual double categories of cospans are always exponentiable, as are the virtual double categories arising from pseudo double categories or from exponentiable multicategories, as studied by Pisani. We give conditions under which the virtual double category of virtual double functors admits composites, following work of Paré for the non-virtual case. We base our work on a general approach to exponentiability for categories of models of limit sketches, which we apply to give new treatments of exponentiability for semicategories, categories, multicategories, and their functors.

2605.20585 2026-05-21 math.AG

On a question of Kollár and Kovács

关于Kollár和Kovács问题的探讨

Jihao Liu

AI总结 本文通过构造一个平坦的射影映射到光滑曲线,其纤维为Cohen-Macaulay且减少,且一般纤维光滑,但纤维的结构sheaf的第一上同调群不恒定,从而回答了Kollár和Kovács的问题。主要结果由生成式AI,特别是Chatgpt 5.5 pro和Rethlas系统获得。

Comments 5 pages. AI generated, human verified

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AI中文摘要

我们通过构造一个平坦的射影映射到光滑曲线,其纤维为Cohen--Macaulay且减少,且一般纤维光滑,但纤维的结构sheaf的第一上同调群不恒定,从而回答了Kollár和Kovács的问题。本文的主要结果由生成式AI,特别是Chatgpt 5.5 pro和Rethlas系统获得。

英文摘要

We answer a question of Kollár and Kovács by constructing a flat projective morphism to a smooth curve whose fibers are Cohen--Macaulay and reduced, whose generic fiber is smooth, and for which the first cohomology of the structure sheaf of the fibers is not constant. The main result of this paper is obtained by generative AI, particularly Chatgpt 5.5 pro and the Rethlas system.

2605.20582 2026-05-21 physics.optics

Gold Bipyramids as a Promising Alternative to Gold Nanorods for Analytical and Biomedical Applications

五边形金双锥体作为分析和生物医学应用中优于金纳米棒的有希望的替代品

Andrey M. Burov, Sergey V. Zarkov, Arina V. Drozd, Igor V. Borisov, Elena G. Zavyalova, Nikolai G. Khlebtsov

AI总结 本研究通过化学蚀刻合成了一种尺寸为75x25 nm的五边形金双锥体,并与其纵向等离子体共振(PR)在753 nm处进行比较,发现双锥体的吸收光谱质量因子显著高于纳米棒。此外,双锥体的SERS增强因子约为纳米棒的三倍,且其PR红移也比纳米棒大三倍,这表明双锥体对周围介质的折射率变化或介电壳厚度的变化更敏感。实验和理论均证实双锥体作为热敏剂在光热治疗中具有高效性,能够有效杀死大肠杆菌。

Comments 37 pages, 7 figures, 65 references

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AI中文摘要

合成了一种尺寸为75x25 nm的五边形金双锥体,其纵向等离子体共振(PR)在753 nm处。为了进行比较,通过化学蚀刻制备了直径为20 nm、长度在95至50 nm之间、纵向PR在945至644 nm的金纳米棒。样品通过紫外-可见光谱和透射电镜(TEM)进行表征。研究表明,双锥体的吸收光谱质量因子显著高于纳米棒。为了比较这些纳米颗粒作为表面增强拉曼散射(SERS)平台的性能,其表面被功能化为硫醇化硝基苯分子(NBT)。结果表明,双锥体的SERS增强因子约为纳米棒的三倍。双锥体在功能化后PR的红移也比具有相同PR的纳米棒大三倍。这与理论估计一致,即双锥体的PR位移对周围介质的折射率变化或介电壳厚度的变化比金纳米球和纳米棒更敏感。此外,双锥体作为光热治疗中将激光辐射转化为热能的热敏剂的高效性通过实验和理论均得到证实。使用双锥体或纳米棒在等离子体共振波长的激光照射下,能够有效杀灭大肠杆菌。

英文摘要

Pentagonal gold bipyramids with dimensions of 75x25 nm and a longitudinal plasmon resonance (PR) at 753 nm are synthesized. For comparison, gold nanorods with a diameter of 20 nm, lengths ranging from 95 to 50 nm, and longitudinal PR from 945 to 644 nm were synthesized by chemical etching. The samples were characterized by UV-vis spectroscopy and transmission electron microscopy (TEM). It is shown that the absorption spectral quality factor of the bipyramids is significantly higher than that of the nanorods. To compare the nanoparticles as platforms for surface-enhanced Raman scattering (SERS), their surface was functionalized with thiolated nitrobenzene molecules (NBT). It is demonstrated that the SERS enhancement factor for the bipyramids is approximately three times higher than that for the nanorods. The red shift of the bipyramids' PR after functionalization with NBT molecules is also about three times greater than for nanorods with the same PR. This agrees with the theoretical estimate of the bipyramids' PR shift being more sensitive to variations in the refractive index of the external medium or the dielectric shell thickness than that of gold nanospheres and nanorods. The high efficiency of the bipyramids as thermosensitizers for converting laser radiation into heat in photothermal therapy is experimentally and theoretically demonstrated. Effective photothermal killing of E. coli was shown upon irradiation with a laser at the plasmon resonance wavelength using nanobipyramids or nanorods.

2605.20579 2026-05-21 math.CO math.MG math.NT

An explicit lower bound for the unit distance problem

单位距离问题的一个显式下界

Will Sawin

AI总结 该研究通过构造代数数域,证明了平面中存在n个点集,其中包含超过n^1.014对距离恰好为1的点对,改进了OpenAI团队最近的工作,并推翻了Erdős的猜想。

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AI中文摘要

我们证明了平面中存在n个点集,其中n可以任意大,且包含超过n^{1.014}对距离恰好为1的点对。这一结果改进了OpenAI团队最近的工作,该团队用一个大于1的非显式指数证明了相同的结果,大幅改进了之前的下界并推翻了Erdős的猜想。该方法是数论性的,依赖于通过Golod-Shafarevich准则构造具有大次数和小判别式的代数数域,并利用许多小范数的素数。

英文摘要

We show that there are sets of $n$ points in the plane with $n$ arbitrarily large that contain more than $n^{1.014}$ pairs of points separated by a distance exactly $1$. This improves on very recent work of a team at OpenAI, who proved the same result with an inexplicit exponent greater than $1$, drastically improving on the best previous lower bound and disproving a conjecture of Erdős. The method is number-theoretic, relying on constructing algebraic number fields of large degree and small discriminant with many primes of small norm via a Golod-Shafarevich criterion argument.

2605.20575 2026-05-21 cond-mat.mtrl-sci

The Dislocation Content of Triple Junctions

三交界处的位错含量

Ian S Winter, R. Daniel Moore, R. E. Rudd, T. Oppelstrup, T. Frolov

AI总结 本文研究了三交界处的位错含量,推导了计算三交界处内在位错含量的必要方程,并展示了该方法可应用于 facet 交界处及其他类型的晶界交界处。通过原子模拟计算钨的位错矢量,揭示了三交界介导的孪生生长过程中的位错反应序列。

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AI中文摘要

三交界是由不同晶界相交形成的线缺陷,存在于所有多晶材料中。尽管长期以来已认识到三交界在微观结构演变中的重要作用,但对其性质仍存在许多不确定性。三交界是能够承载位错含量的线缺陷。然而,尚未建立通用的计算该含量的方法。在本工作中,我们推导出计算三交界内在位错含量的必要方程,其三色图案形成巧合位点晶格。我们进一步表明,该方法可轻松应用于 facet 交界,并原则上适用于任何可以定义巧合位点晶格的晶界交界。我们将此形式化应用于钨的原子模拟中,计算孪生晶粒成核和生长过程中 facet 交界和三交界形成的伯格矢量。通过追踪三交界伯格矢量及其核心结构的演变,我们揭示了由三交界介导的孪生生长过程中各个线缺陷反应的序列。

英文摘要

Triple junctions, line defects formed by the intersection of different grain boundaries, exist within all polycrystalline materials. While it has long been recognized that triple junctions could play an important role in microstructural evolution, there remains much uncertainty regarding their properties. Triple junctions are line defects capable of carrying dislocation content. However, no general method for calculating this content has been established. In this work, we derive the necessary equations to calculate the intrinsic dislocation content of a triple junction whose trichromatic pattern forms a coincidence site lattice. We further show that this approach can be easily applied to facet junctions, and in principle, any type of grain boundary junction for which a coincidence site lattice can be defined. We apply this formalism to atomistic simulations of tungsten to compute the Burgers vectors of a facet junction and a triple junction formed during twin grain nucleation and growth from a free surface. By tracking the evolution of the triple junction's Burgers vector and its core structure, we reveal the sequence of individual line defect reactions responsible for triple-junction-mediated twin growth.

2605.20574 2026-05-21 gr-qc

Post-Newtonian orbital mechanics around a black hole in modified gravity

黑洞周围修正引力下的后牛顿轨道力学

Ioannis Liodis, Gernot Heissel, Rita Mastroioanni, Jai Grover, Dario Izzo

AI总结 本文研究了在修正引力(MOG)框架下,S星围绕银河中心超大质量黑洞轨道的扰动,探讨了MOG对轨道元素、观测参数及暗物质场景的潜在退化效应,并通过数值积分后牛顿方程验证了MOG对轨道进动的显著影响。

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AI中文摘要

标量-张量-矢量引力,也称为修正引力(MOG),已成为广义相对论(GR)的一种替代理论。它旨在解释天体物理现象而无需引入暗物质。围绕银河中心超大质量黑洞的S星提供了一个独特的机会来测试MOG的预测,因为轨道测量高度精确。我们研究了在MOG下S星轨道的扰动,重点是轨道元素、右 ascension、 declination 和径向速度等观测参数以及与暗物质场景的潜在退化效应。我们基于MOG框架,数值积分了S星的首后牛顿运动方程,考虑了时空几何和第五力的贡献。我们分析了轨道元素的时间演化,并将轨道投影到天空平面以评估与GR的偏差。此外,我们比较了MOG引起的效应与预期的暗物质分布效应。我们发现MOG显著改变了轨道进动,特别是对于较高的MOG参数α值。对于足够大的α或长时间的观测基线,观测参数的偏差幅度可以达到当前观测精度的量级。此外,我们证明MOG效应可以模仿暗物质分布的影响,特别是在近地点论证中,并揭示了MOG与GR与电磁学之间未被探索的联系。MOG对恒星轨道的影响不同于GR预测的影响,可以通过S星的高精度天体测量和光谱学测量来检验。然而,与暗物质信号的潜在退化需要仔细解释观测数据。

英文摘要

Scalar-tensor-vector gravity, also known as modified gravity (MOG), has emerged as an alternative to General Relativity (GR). It aims to explain astrophysical phenomena without invoking dark matter. The S-stars orbiting the supermassive black hole at the Galactic centre provide a unique opportunity to test the predictions of MOG because the orbital measurements are highly precise. We investigate the perturbations in the orbits of S-stars under MOG, focusing on the effects on orbital elements, observables such as right ascension, declination, and radial velocity, and the potential degeneracy with dark matter scenarios. We numerically integrated the first post-Newtonian equations of motion for S-stars within the MOG framework, considering contributions from the space-time geometry and the fifth force. We analysed the time evolution of orbital elements and projected the orbits onto the plane of the sky to assess deviations from GR. Furthermore, we compared the MOG-induced effects with those expected from a dark matter distribution. We found that MOG significantly alters the orbital precession, particularly for higher values of the MOG parameter $α$. For sufficiently large $α$ or long observational baselines, the deviations in the observables can reach amplitudes comparable to current observational precision. Furthermore, we demonstrate that MOG effects can mimic those of a dark matter distribution, particularly in the argument of pericentre, and we reveal an unexplored connection between MOG and GR with electromagnetism. The effects of MOG on stellar orbits are distinct from those predicted by GR and can be tested with precise astrometric and spectroscopic measurements of the S-stars. However, a potential degeneracy with dark matter signatures necessitates careful interpretation of observational data.

2605.20573 2026-05-21 cond-mat.str-el

Distinct lattice and charge excitations in AV3Sb5 kagome superconductors

AV3Sb5双网格超导体中的不同晶格和电荷激发

Dongjin Oh, Stefan Enzner, Lennart Klebl, Harley D. Scammell, Julian Ingham, Tim Wehling, Giorgio Sangiovanni, Ronny Thomale, Ahmet Kemal Demir, Connor Occhialini, Dirk Wulferding, Ziqiang Wang, Andrea C. Salinas, Stephen D. Wilson, Riccardo Comin

AI总结 研究通过角分辨极化拉曼光谱揭示了AV3Sb5中晶格和电荷自由度在CDW相中的不同行为,揭示了材料依赖的对称性破缺现象的起源。

Comments 7 pages, 4 figures

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AI中文摘要

AV3Sb5双网格超导体家族(A=Cs, Rb, K)为探索多样的电子对称性破缺现象提供了丰富的平台,包括超导性和各种密度波有序形式。尽管这些化合物在正常态下具有相同的晶格结构,但进入电荷密度波(CDW)相时表现出不同的对称性破缺形式,其微观起源仍然不明。本文通过角分辨极化拉曼光谱研究了AV3Sb5中的晶格和电荷自由度。我们的全面极化分辨测量发现,在CDW相中E2g声子模式的二重简并解除,此前仅在CsV3Sb5中报告出3 GHz分裂,也普遍出现在另外两种化合物中。相比之下,集体CDW激发在不同碱金属物种中表现出显著不同的极化依赖性。这些晶格和电荷通道中的不同行为为CDW相中出现的神秘材料依赖对称性破缺现象提供了关键见解。此外,我们的实验结合第一性原理计算和有效哈密顿量模型,揭示了AV3Sb5双网格超导体中电荷有序结构的性质。

英文摘要

The kagome superconductor family AV3Sb5 (A=Cs, Rb, K) provides a rich platform for exploring diverse electronic symmetry breaking phenomena, including superconductivity and various forms of density wave orders. Although these compounds share the identical lattice structure in the normal state, they exhibit distinct forms of symmetry breaking upon entering the charge density wave (CDW) phase, and the microscopic origin of which remain elusive. Here, we investigate the lattice and charge degrees of freedom in AV3Sb5 using angle-resolved polarized Raman spectroscopy. Our comprehensive polarization-resolved measurements reveal that the lifting of the twofold-degeneracy of the E2g phonon mode in the CDW phase-previously reported only in CsV3Sb5 with a 3 GHz splitting-also appears ubiquitously in the other two compounds. In contrast, the collective CDW excitations exhibit markedly different polarization dependences depending on the alkali-metal species. These distinct behaviors in the lattice and charge channels provide crucial insight into the enigmatic material-dependent symmetry breaking phenomena that appear in the CDW phase. Furthermore, our experiments, together with first-principles calculations and an effective Hamiltonian model, shed light on the nature of the charge order structure in AV3Sb5 kagome superconductors.

2605.20572 2026-05-21 math.ST stat.ME stat.TH

Minimax unbiased estimation for finite populations with bounded outcomes

有限总体的最小最大无偏估计:具有有界结果

P. M. Aronow, Patrick Lopatto

AI总结 本文研究了在每个结果满足已知边界的情况下,对有限总体总和进行设计无偏估计的问题,推导了在矩形参数空间下的最坏情况平方误差下界,并证明了当单元包含指示符成对独立时,最小最大估计器为中点差分Horvitz-Thompson估计器。

Comments 14 pages

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AI中文摘要

我们研究了在每个结果满足已知边界$y_i\in[a_i,b_i]$的情况下,对有限总体总和$\sum_{i=1}^N y_i$进行设计无偏估计的问题。对于任何具有包含概率$\pi_i>0$的抽样设计,我们证明了在矩形参数空间下的最坏情况平方误差的紧下界。该下界当且仅当单元包含指示符成对独立时才能达到,此时最小最大估计器是中点差分Horvitz-Thompson估计器$\sum_{i=1}^N m_i+\sum_{i\in S}(y_i-m_i)/\pi_i$,其中$m_i=(a_i+b_i)/{2}$。然后我们在约束$\sum_i \pi_i\le n$下解决联合设计与估计问题。我们发现,最小最大策略以概率$\pi_i^\ast=\min(1,c (b_i-a_i))$独立抽取单元,其中$c>0$被选择使得$\sum_i \pi_i^\ast=n$,并使用中点差分估计器。这将Gabler (1990)的线性最小最大结果扩展到完整的设计无偏估计器类。我们还证明该估计器在无偏估计器中是可接受的,并且是仿射等变的。

英文摘要

We study design-unbiased estimation of the finite-population total $\sum_{i=1}^N y_i$ when each outcome satisfies known bounds $y_i\in[a_i,b_i]$. For any sampling design with inclusion probabilities $π_i>0$, we prove a sharp lower bound on the worst-case squared error over the rectangular parameter space. This bound is attained if and only if the unit inclusion indicators are pairwise independent, in which case the minimax estimator is the midpoint-differenced Horvitz-Thompson estimator $\sum_{i=1}^N m_i+\sum_{i\in S}(y_i-m_i)/π_i$, with $m_i=(a_i+b_i)/{2}$. We then solve the joint design-and-estimation problem under the constraint $\sum_i π_i\le n$. We find that a minimax strategy samples units independently with probabilities $π_i^\ast=\min(1,c (b_i-a_i))$ where $c>0$ is chosen so that $\sum_i π_i^\ast=n$, and uses the midpoint-differenced estimator. This extends Gabler (1990)'s linear minimax result to the full class of design-unbiased estimators. We also show that the estimator is admissible among unbiased estimators and affine equivariant.

2605.20571 2026-05-21 physics.flu-dyn

Multi-scale flow analysis for scale-aware urban-canopy models

多尺度流动分析用于尺度感知的城区 canopy 模型

Jingzi Huang, Maarten van Reeuwijk

AI总结 本文研究了在高分辨率数值天气预报模型中,城区异质性部分解析以及传统城区 canopy 模型假设的可靠性问题,通过多尺度粗粒化框架分析了布里斯托尔大学校园的建筑解析大涡模拟,确定了城区特征长度尺度,并评估了分布式阻力和湍流应力参数化在不同分辨率下的适用性。

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AI中文摘要

随着数值天气预报(NWP)模型向 hectometric 分辨率发展,它们越来越多地进入一个 regime,其中城区异质性仅部分解析,而传统城区 canopy 模型(UCMs)的假设变得存疑。为解决这一尺度差距,我们应用多尺度粗粒化框架(van Reeuwijk 和 Huang 2025,Boundary-Layer Meteorology)到布里斯托尔大学校园的建筑解析大涡模拟(LES)。考虑了两种相关形态:原始布局具有大开放空间对比和修改后的配置,这些区域被填充。通过系统地过滤 LES 场,我们量化了流动异质性如何随分辨率演变,并识别了一个特征城区长度尺度,在此尺度上解析和未解析的变异性相等。此尺度强烈依赖于形态,原始布局约为 256 米,修改后的案例为 64 米,表明邻里尺度组织在与下一代 NWP 相关的分辨率中仍然重要。我们随后对分布式阻力和湍流应力参数化进行了 a priori 评估。从理想化几何中衍生的参数化在足够粗的分辨率下表现尚可,其中水平输送可忽略,流动近似均匀。在更细的分辨率下,其保真度迅速下降,因为异质性和形态的滤波器到滤波器变化增加,真实布局的限制比理想化立方体阵列更强。总体而言,结果表明,城区参数化适用性依赖于模型分辨率与形态依赖的异质性尺度之间的关系,为开发适用于高分辨率 NWP 的尺度感知 UCMs 提供了系统方法。

英文摘要

As Numerical Weather Prediction (NWP) models approach hectometric resolution, they increasingly enter a regime where urban heterogeneity is only partially resolved and the assumptions underlying conventional urban canopy models (UCMs) become questionable. To address this scale gap, we apply a multi-scale coarse-graining framework (van Reeuwijk and Huang 2025, Boundary-Layer Meteorology) to building-resolving Large-Eddy Simulations (LES) of the University of Bristol campus. Two related morphologies are considered: an original layout with large open-space contrasts and a modified configuration with these regions infilled. By systematically filtering the LES fields, we quantify how flow heterogeneity evolves with resolution and identify a characteristic urban length scale at which resolved and unresolved variability are comparable. This scale is strongly morphology-dependent, with values of about 256 m for the original layout and 64 m for the modified case, showing that neighbourhood-scale organisation can remain important at resolutions relevant to next-generation NWP. We then perform an a priori assessment of distributed drag and turbulent-stress parameterisations. Parameterisations derived from idealised geometries perform reasonably well only at sufficiently coarse resolutions, where horizontal transport is negligible and the flow appears approximately homogeneous. At finer resolutions, their fidelity degrades rapidly because of increasing heterogeneity and filter-to-filter variability in morphology, with stronger limitations in realistic layouts than in idealised cuboid arrays. Overall, the results show that the applicability of urban parameterisations depends critically on the relationship between model resolution and a morphology-dependent heterogeneity scale, providing a systematic route for developing scale-aware UCMs for high-resolution NWP.

2605.20570 2026-05-21 gr-qc

ModMax-black hole surrounded by cloud of strings in Bumblebee gravity

ModMax黑洞周围环绕弦云在Bumblebee引力中的光学性质

Fernando M. Belchior, Allan R. P. Moreira, Abdelmalek Bouzenada, Faizuddin Ahmed

AI总结 本文研究了ModMax黑洞周围环绕弦云在Bumblebee引力框架下的光学、热力学和散射特性,分析了黑洞的热力学性质,包括霍金温度、熵及其他相关热力学量,并探讨了不同扰动场在该黑洞背景中传播时的灰色体因子(GFs),评估了不同自旋场的吸收概率和能量辐射率,揭示了系统参数如洛伦兹对称破坏参数、弦云参数、ModMax参数、电荷和黑洞质量对辐射和散射过程的物理影响。

Comments 29 pages and 11 figures

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AI中文摘要

在本文中,我们研究了在Bumblebee引力框架下,环绕弦云的ModMax黑洞的光学、热力学和散射性质。我们详细分析了该黑洞的热力学性质,包括霍金温度、熵及其他相关热力学量,并探讨了结果。此外,我们研究了与不同扰动场在该黑洞背景中传播时的发射相关的灰色体因子(GFs)。特别是,我们考虑了自旋0标量场、自旋1电磁场和自旋2引力子场,并评估了相应的吸收概率和能量辐射率。我们的分析展示了光学特性、热力学和GFs如何依赖于系统的底层参数,如洛伦兹对称破坏参数、弦云参数、ModMax参数、电荷和黑洞质量,从而提供了这些参数对黑洞周围辐射和散射过程的物理影响的全面理解。

英文摘要

In this article, we investigate the optical, thermodynamic, and scattering properties of a ModMax black hole surrounded by a cloud of strings within the framework of Einstein-bumblebee gravity. We then analyze in detail the thermodynamic properties of this black hole, including the Hawking temperature, entropy, and other relevant thermodynamic quantities, and examine the outcomes. Furthermore, we study the greybody factors (GFs) associated with the emission of various perturbative fields propagating in this black hole background. In particular, we consider spin-0 scalar fields, spin-1 electromagnetic fields, and spin-2 graviton fields, and evaluate the corresponding absorption probabilities and energy emission rates. Our analysis demonstrates how the optical features, thermodynamics and GFs depend on the underlying parameters of the system, such as the Lorentz symmetry violation parameter, the cloud of strings parameter, the ModMax parameter, the electric charge, and the black hole mass, thereby providing a comprehensive understanding of the physical effects of these parameters on the radiation and scattering processes around the black hole.

2605.20568 2026-05-21 math.GR

On dense free subgroups of Lie groups -- revisited

关于李群的稠密自由子群——再论

Emmanuel Breuillard, Tsachik Gelander

AI总结 本文研究了连通李群中稠密子群的性质,证明每个稠密子群都包含由2d个元素生成的稠密子群,并详细讨论了Cartan分解中两个主导项的比率与收缩投影变换量化特征之间的关系。

Comments 6 pages, 0 figures. This note supplements our 2002 paper arXiv:math/0206236

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AI中文摘要

我们证明了每个连通李群G的稠密子群都包含一个由2d个元素生成的稠密子群,其中d=dim(G)。我们还给出了收缩投影变换的量化特征的详细证明,该特征以Cartan分解中两个主导项的比率来表征。

英文摘要

We show that every dense subgroup of a connected Lie group G contains a dense subgroup generated by 2d elements, where d=dim(G). We also give a detailed proof for the quantitive characterization of a contracting projective transformation in terms of the ratio between the two leading terms in its Cartan decomposition.

2605.20567 2026-05-21 stat.ME

Meta-analysis and network meta-analysis of time-to-event outcomes with non-proportional hazards: a Bayesian time-varying hazard ratio approach

时间至事件结局的元分析与网络元分析:基于贝叶斯时间变化危险比方法的非比例危险处理

Rhiannon K Owen, Keith R Abrams

AI总结 本文提出了一种基于贝叶斯时间变化危险比方法的元分析和网络元分析方法,用于处理时间至事件结局中非比例危险的情况,通过分析化疗与标准治疗在晚期复发胃癌中的疗效,并在晚期BRAF突变黑色素瘤中评估总生存率,展示了该方法在非比例危险假设不成立时的有效性。

Comments 23 pages, 13 figures, 3 tables & Presented as an Oral Contribution at International Society for Clinical Biostatistics (ISCB) Conference (ISCB-46), Basel, August 27, 2025

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AI中文摘要

背景:在进行时间至事件(TTE)结局的元分析,尤其是在健康技术评估(HTA)背景下时,通常使用危险比(HR)尺度。然而,当某些研究显示非比例危险时会出现问题。尽管已有多种方法被推荐,但它们的使用受到复杂性和结果在HTA中应用的便利性限制。替代方法是假设在Cox比例危险模型中每个研究内存在治疗-时间交互作用,并对由此产生的治疗和交互系数进行双变量元分析,从而获得总体时间变化危险比(TVHR)。方法:该TVHR方法被应用于比较化疗与标准治疗在晚期复发胃癌的元分析,其中无进展生存期(PFS)是结局。该方法也应用于评估晚期BRAF突变黑色素瘤的网络元分析(NMA)中的总生存期(OS)。结果:在晚期胃癌的元分析中,有五项试验显示出PFS的非比例危险证据。使用TVHR模型得到的HR在0.5年时为0.83(CrI:0.75-0.91),在3.5年时为0.99(CrI:0.79-1.23)。在晚期BRAF突变黑色素瘤NMA中,三项研究显示出OS的非比例危险证据。使用TVHR模型,nivolumab加ipilimumab在第七个月后持续优于对照组,HR从一年时的0.37(CrI:0.26-0.51)提高到五年时的0.24(CrI:0.12-0.45)。结论:当比例危险假设不成立时,采用TVHR方法进行TTE结局的元分析或NMA,能够提供直观的解决方案,便于在HTA中使用。

英文摘要

Background: Often when undertaking meta-analyses of time-to-event (TTE) outcomes, especially in a Health Technology Assessment context, a hazard ratio (HR) scale is used. However, issues arise when there is evidence of non-proportional hazards in some of the studies included. A number of methods have been advocated, but their use has been limited by either their complexity and/or the ease with which their results can be used in HTA. An alternative approach is to assume a treatment-log(time) interaction within a Cox proportional hazards model for each study, and to then undertake a bivariate meta-analysis of the resulting treatment and interaction coefficients, so that an overall time-varying HR (TVHR) can be obtained. Methods: A TVHR approach was applied to a meta-analysis of chemotherapy compared to Standard of Care for advanced recurrent gastric cancer, and in which Progression-Free Survival (PFS) was an outcome. The approach was also applied to a network meta-analysis (NMA) evaluating overall survival (OS) in advanced BRAF-mutated melanoma. Results: Five trials in the advanced gastric cancer meta-analysis displayed evidence of non-proportional hazards for PFS. Using a TVHR model produced HRs ranging from 0.83 (CrI:0.75-0.91) at 0.5 years to 0.99 (CrI:0.79-1.23) at 3.5 years. Three studies showed evidence of non-proportional hazards in the advanced BRAF-mutated melanoma NMA for OS. Using a TVHR model, nivolumab plus ipilimumab demonstrated consistent superiority from month 7 onwards, with a HR improving from 0.37 (CrI:0.26-0.51) at one year to 0.24 (CrI:0.12-0.45) at five years. Conclusions: A TVHR approach to the meta-analysis or NMA of TTE outcomes when the proportional hazards assumption appears not to hold, produces an intuitive solution which can be readily used in HTA.

2605.20565 2026-05-21 physics.flu-dyn

Simulations of Particle-Laden Flows with Large Dispersed-Phase Size Disparities Using Highly Scalable Parallel Adaptive Methods

具有大分散相尺寸差异的粒子流模拟:使用高度可扩展的并行自适应方法

Linfeng Jiang, Enrico Calzavarini, Dominik Krug

AI总结 本文提出了一种高度可扩展的并行自适应方法,用于模拟具有大分散相尺寸差异的多相流,通过耦合格子玻尔兹曼方法与浸没边界方法,在动态自适应八叉树网格上实现高效并行计算,验证了该方法在气泡-颗粒碰撞等多尺度问题中的准确性和鲁棒性。

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AI中文摘要

多相流中涉及大尺度差异的分散组分(如浮选中毫米级气泡与微米级矿物颗粒的碰撞)的数值模拟提出了显著的计算挑战。在均匀网格上准确解析有限大小物体的薄边界层并跟踪大量小颗粒,往往在大湍流域中成本过高。为此,本文提出了一种并行可扩展的计算框架,将格子玻尔兹曼方法与浸没边界方法耦合在动态自适应八叉树网格上。开发了高效的并行主机单元搜索算法,显著加速了分布式非结构化网格上拉格朗日点的跟踪。代码的准确性和鲁棒性通过经典基准测试严格验证,包括振荡圆柱诱导的流动和球体沉降。该框架应用于气泡-颗粒碰撞的多尺度问题。在静止流中,模拟准确捕捉了流体动力学拦截机制,重现了理论碰撞效率与颗粒-气泡尺寸比平方成正比的标度律。此外,该框架还应用于完全解析的气泡与惯性点颗粒在各向同性湍流中的相互作用模拟。

英文摘要

The numerical simulation of multiphase flows involving dispersed components with large scale disparities, such as the collisions between millimeter-sized bubbles and micron-sized mineral particles in flotation, poses a significant computational challenge. Accurately resolving the thin boundary layers of finite-size objects while tracking massive numbers of small particles within a large turbulent domain is often prohibitively expensive on uniform grids. To address this, we present a parallel scalable computational framework that couples the lattice Boltzmann method with the immersed boundary method on a dynamically adaptive octree grid. A key algorithm is developed for the efficient parallel host-cell searching, which significantly accelerates the tracking of Lagrangian points on distributed unstructured grids. The accuracy and robustness of the code are rigorously validated against canonical benchmarks, including the flow induced by an oscillating cylinder and the sedimentation of a sphere. The framework is applied to the multiscale problem of bubble-particle collisions. In quiescent flow, the simulations accurately capture the hydrodynamic interception mechanism, reproducing the theoretical collision efficiency scaling law proportional to the square of the particle-to-bubble size ratio. Furthermore, the framework is applied to the simulation of fully resolved bubbles interacting with inertial point particles in homogeneous isotropic turbulence.

2605.20562 2026-05-21 gr-qc

Convergence of post-Newtonian for quasi-circular non-precessing comparable mass ratios BBHs

双黑洞准圆形非预cession质量比的后牛顿展开收敛性

Dongze Sun, Béatrice Bonga, Leo C. Stein, Guido Da Re

AI总结 本文研究了双黑洞准圆形非预cession质量比系统中后牛顿展开系列的收敛性,通过比较后牛顿能量流与高精度数值相对论模拟结果,发现随着轨道速度增加,后牛顿阶数越高,能量流与NR的差异越小,但存在局部极值点,表明最优截断阶数不能仅通过第一个局部极小值确定。

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AI中文摘要

后牛顿理论为二黑洞早期 inspiral 的建模提供了解析基础。然而,作为一种渐近级数,后续的后牛顿阶数并不一定能提高与完整非线性动力学的一致性。虽然在极端质量比极限中已进行了探索,但与当前观测最相关的等质量系统在高后牛顿阶数下尚未系统地进行基准测试。我们通过将后牛顿能量流与未来零无穷处的长时高精度数值相对论 (NR) 模拟进行比较,研究了非自转和准圆形系统的后牛顿级数的收敛性。为了实现一致的格栅比较,我们将两种描述置于同一BMS框架中,并通过拟合NR波形在早期inspiral中的参数来校准内在的后牛顿参数。我们发现,对于轨道速度v≈0.45以下,更高阶的后牛顿阶数继续减少后牛顿-NR流量差异,其中不完整的6PN在所考虑的阶数中提供了最佳的一致性。随着后牛顿阶数的增加,改进是非单调的,存在局部极值点在2.5PN和4PN附近。这表明,后牛顿级数的最佳截断阶数不能仅通过能量流残差中的第一个局部极小值确定,这与早期工作的建议相悖。随着v接近≈0.5,接近最内圆轨道时,更高阶的后牛顿阶数不再改善NR与后牛顿之间的协议,表明收敛性丧失。这些结果鼓励继续进行高阶后牛顿计算,并澄清验证它们所需的NR精度。

英文摘要

Post-Newtonian (PN) theory provides the analytic foundation for modeling the early inspiral of binary black holes. However, as an asymptotic series, successive PN orders do not necessarily improve agreement with the full nonlinear dynamics. While this has been explored in the extreme-mass-ratio limit, comparable-mass systems most relevant to current observations have not been benchmarked as systematically at high PN order. We study the convergence of the PN series for non-spinning and quasi-circular systems by comparing the PN energy flux at future null infinity to a long, high-accuracy numerical relativity (NR) simulation. To enable a gauge-consistent comparison, we place both descriptions in the same BMS frame and calibrate the intrinsic PN parameters by fitting to the NR waveform in the early inspiral. We find that for orbital velocities $v\lesssim0.45$, higher PN orders continue to reduce the PN--NR flux discrepancy, with (incomplete) 6PN providing the best agreement among the orders considered. The improvement with PN order is non-monotonic with local extrema around 2.5PN and 4PN. This implies that the optimal truncation order of the PN series cannot be identified from the first local minimum in the energy flux residuals, contrary to suggestions in earlier work. As $v$ approaches $\sim 0.5$ near the innermost circular orbit, higher PN orders no longer improve the agreement between NR and PN, indicating a loss of convergence. These results motivate continued high-order PN calculations and clarify the NR accuracy needed to validate them.

2605.20553 2026-05-21 math.AP

Long-Time Stability Analysis for Stochastic Evolution Equations with Multiplicative Noise

关于具有乘性噪声的随机演算方程的长期稳定性分析

Abdellatif Elgrou, Abdelaziz Rhandi, Jawad Salhi

AI总结 本文研究了一类在Hilbert空间中具有乘性噪声的线性随机演算方程的长期稳定性行为,建立了p阶矩和几乎确定指数稳定性条件,揭示了主特征值、漂移系数和噪声强度之间的相互作用,并展示了这两种稳定性概念的关系。还给出了几种随机偏微分方程的应用,以及全离散谱伽辽金方法与隐式欧拉-马尔可夫方案在离散水平上保持这些稳定性性质的证明,并通过数值模拟验证了理论结果。

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AI中文摘要

在本文中,我们研究了一类在Hilbert空间中具有乘性噪声的线性随机演算方程的长期稳定性行为。建立了p阶矩和几乎确定指数稳定性的充分条件,强调了主特征值、漂移系数和噪声强度之间的相互作用。还澄清了这两种稳定性概念之间的关系。给出了几种随机偏微分方程的应用。此外,展示了全离散谱伽辽金方法与隐式欧拉-马尔可夫方案在离散水平上保持这些稳定性性质。最后,提供了数值模拟以验证理论结果。

英文摘要

In this paper, we study the long-time stability behavior of a class of linear stochastic evolution equations in a Hilbert space with multiplicative noise. Explicit sufficient conditions for $p$-th moment and almost sure exponential stability are established, highlighting the interplay between the principal eigenvalue of the governing operator, the drift coefficient, and the noise intensity. The relationship between these two notions of stability is also clarified. Applications to several stochastic partial differential equations are presented. In addition, a fully discrete spectral Galerkin method together with the implicit Euler--Maruyama scheme is shown to preserve these stability properties at the discrete level. Finally, numerical simulations are provided to confirm the theoretical results.

2605.20550 2026-05-21 math.ST stat.TH

Kernel Density Estimation under $C^{1,1}$ Regularity: AMISE, Weak Curvature, and Plug-in Bandwidths

核密度估计在$C^{1,1}$正则性下:AMISE、弱曲率和插件带宽

Alireza Kabgani, Elaheh Lotfian

AI总结 本文研究了在$C^{1,1}$正则性条件下核密度估计的AMISE理论,提出了弱曲率概念,并在不假设经典二阶导数连续的情况下,推导出AMISE公式、最优带宽和Epanechnikov核最优性。

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AI中文摘要

经典的核密度估计通常通过点wise泰勒展开推导出AMISE和最优带宽,这需要两次连续可导。这一假设比必要强,排除了自然密度,这些密度来自阈值模型、制度变化和鲁棒混合模型,其中一阶导数可能是Lipschitz的,而曲率可能是尖点、不连续或仅弱定义的。我们证明在更弱的条件$f\in C^{1,1}(\mathbb{R})$下,经典AMISE理论仍然有效。点wise $C^2$泰勒展开被基于弱二阶导数的积分泰勒表示所替代,因此$R(f'')$被解释为弱曲率功能。在$f\in C^{1,1}(\mathbb{R})$和$f''\in L^2(\mathbb{R})$的条件下,我们恢复了经典的AMISE公式、$n^{-1/5}$最优带宽和Epanechnikov核最优性,而无需假设连续的经典二阶导数。我们还提出了一种广义曲率插件带宽选择器,证明其在比率一致曲率估计下的AMISE等价性,并建立了留一法U统计量曲率估计器的一致性。使用弱Hessian的多元扩展恢复了标量带宽率$n^{-4/(d+4)}$。

英文摘要

Classical kernel density estimation usually derives the AMISE and optimal bandwidth from a pointwise Taylor expansion, which requires twice continuous differentiability. This assumption is stronger than necessary and excludes natural densities arising from threshold models, regime changes, and robust mixture models, where the first derivative may be Lipschitz while the curvature is kinked, discontinuous, or only weakly defined. We show that the classical AMISE theory remains valid under the weaker condition $f\in C^{1,1}(\mathbb{R})$. The pointwise $C^2$ Taylor expansion is replaced by an integral Taylor representation based on the weak second derivative, so that $R(f'')$ is interpreted as a weak-curvature functional. Under $f\in C^{1,1}(\mathbb{R})$ and $f''\in L^2(\mathbb{R})$, we recover the classical AMISE formula, the $n^{-1/5}$ optimal bandwidth, and Epanechnikov kernel optimality without assuming a continuous classical second derivative. We also propose a generalized-curvature plug-in bandwidth selector, prove its first-order AMISE equivalence under ratio-consistent curvature estimation, and establish consistency of a leave-one-out U-statistic curvature estimator. A multivariate extension using weak Hessians recovers the scalar-bandwidth rate $n^{-4/(d+4)}$.

2605.20548 2026-05-21 cs.MA

What Do Agents Communicate? Characterizing Information Exchange in Multi-Agent Systems

智能体通信什么?多智能体系统中信息交换的特征化

Yong Jin Chun, Iftekhar Ahmed

AI总结 本文研究了多智能体系统中信息交换的核心问题,发现缺乏推理和验证的信息会显著降低性能,并提出了一种增强技术来恢复通信中的关键信息,从而提高了系统性能。

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AI中文摘要

大型语言模型(LLMs)已经使协作多智能体(MA)系统成为可能,其中交互智能体通过多样化的推理和迭代优化来提高性能。然而,这些系统仍然容易受到错误传播的影响,其中早期阶段的信息会降级下游推理。为了解决这个问题,我们对智能体间通信进行了系统分析,以确定哪些信息驱动MA性能。我们发现,智能体间通信中缺乏推理和验证会显著降低性能。基于这些见解,我们提出了Category-Aware Recovery Augmentation(技术),该技术在通信中强制存在关键信息。该技术恢复了多达86.2%的失败案例。我们的结果强调了信息质量在有效MA协作中的关键作用。我们的代码可在https://anonymous.4open.science/r/cara_mas获取。

英文摘要

Large Language Models (LLMs) have enabled collaborative Multi-Agent (MA) systems, where interacting agents improve performance through diverse reasoning and iterative refinement. However, these systems remain vulnerable to error propagation, where early-stage information degrades downstream reasoning. To address this, we conduct a systematic analysis of inter-agent communication to identify which information drives MA performance. We find that the absence of reasoning and verification in inter-agent communication significantly degrades performance. Based on these insights, we propose Category-Aware Recovery Augmentation (technique), which enforces the presence of critical information during communication. recovers up to 86.2% of failed cases. Our results highlight the key role of information quality in effective MA collaboration. Our code is available at https://anonymous.4open.science/r/cara_mas

2605.20546 2026-05-21 cs.CR cs.NI

Detecting Data Exfiltration through I2P Anonymity Networks: A Two-Phase Machine Learning Approach

通过I2P匿名网络检测数据外泄:一种两阶段机器学习方法

Siddique Abubakr Muntaka, Muntaka Mohammed, Mansuru Mikail Azindo, Ibrahim Tanko, Franco Osei-Wusu, Edward Danso Ansong, Benjamin Yankson, Oliver Kornyo, Foster Yeboah, Jones Yeboah, Richmond Adams, Pulcheria Serwaa

AI总结 本文提出了一种两阶段机器学习模型,利用SafeSurf Darknet 2025数据集对I2P流量进行分析,通过随机森林分类器实现了99.96%的准确率,进一步通过XGBoost对I2P流量进行行为分析,识别外泄或合法活动,为运营网络环境中的I2P流量检测和威胁优先级评估提供了有效方法。

详情
AI中文摘要

The Invisible Internet Project (I2P) provides strong anonymity through garlic routing and distributed network architecture, making it attractive for legitimate privacy needs. Nevertheless, the same properties can be exploited by malicious actors to steal sensitive information from corporate networks without detection. Current network security measures often fail to detect I2P traffic, and existing literature has focused primarily on protocol-level traffic identification without addressing behavioral threat assessment. This paper proposes a two-stage machine-learning model for I2P traffic analysis using the SafeSurf Darknet 2025 dataset comprising 184,548 network flows. Phase 1 achieved 99.96% accuracy in distinguishing I2P traffic from normal network traffic using a Random Forest classifier, with only 2 false positives among 32,318 normal flows. Phase 2 performed behavioral analysis on traffic identified as I2P, classifying it as either exfiltration or legitimate activity, achieving 91.11% accuracy using XGBoost. The system demonstrates that tree-based ensemble methods substantially outperform deep neural networks and support vector machines for this task. Feature importance analysis indicates that the most discriminative features are packet timing and flow duration. These findings establish that accurate I2P traffic detection and threat prioritization are achievable in operational network environments, enabling security teams to focus resources on high-risk events rather than monitoring all encrypted traffic.

英文摘要

The Invisible Internet Project (I2P) provides strong anonymity through garlic routing and distributed network architecture, making it attractive for legitimate privacy needs. Nevertheless, the same properties can be exploited by malicious actors to steal sensitive information from corporate networks without detection. Current network security measures often fail to detect I2P traffic, and existing literature has focused primarily on protocol-level traffic identification without addressing behavioral threat assessment. This paper proposes a two-stage machine-learning model for I2P traffic analysis using the SafeSurf Darknet 2025 dataset comprising 184,548 network flows. Phase 1 achieved 99.96% accuracy in distinguishing I2P traffic from normal network traffic using a Random Forest classifier, with only 2 false positives among 32,318 normal flows. Phase 2 performed behavioral analysis on traffic identified as I2P, classifying it as either exfiltration or legitimate activity, achieving 91.11% accuracy using XGBoost. The system demonstrates that tree-based ensemble methods substantially outperform deep neural networks and support vector machines for this task. Feature importance analysis indicates that the most discriminative features are packet timing and flow duration. These findings establish that accurate I2P traffic detection and threat prioritization are achievable in operational network environments, enabling security teams to focus resources on high-risk events rather than monitoring all encrypted traffic.

2605.20542 2026-05-21 quant-ph

Mean-field and fluctuation dynamics in off-resonant two-mode atom-field interactions

在非共振双模原子-场相互作用中的平均场与涨落动力学

Luis Medina-Dozal, Alejandro R. Urzúa, Carlos A. González-Gutiérrez, José Récamier

AI总结 本文研究了双能级系统与两个量化电磁场模式的耦合,基于Jaynes-Cummings框架。虽然单模模型由于守恒的激发数而可解,但双模模型扩展面临挑战:尽管总激发数守恒,每个不变子空间无限维,无法得到闭式解。本文通过分离动力学为主导的可解 semiclassical 组件和处理剩余量子涨落的单位元变换序列,验证了方法在非共振区域的准确性,能够高效计算原子翻转、场可观测量和保真度。

Comments 20 pages, 6 figures

详情
AI中文摘要

我们研究了在Jaynes-Cummings框架下,一个双能级系统与两个量化电磁场模式的耦合。虽然单模模型由于其守恒的激发数而恰好可解,从而产生有限维的不变子空间,但双模模型的扩展则面临根本性挑战:尽管总激发数仍然守恒,但每个不变子空间都是无限维的,从而阻止了闭式解析解的获得。我们的方案将动力学分为一个主导的、恰好可解的 semiclassical 组件,即原子与两个模式的平均场相互作用,以及通过一系列保持关键量子特征的单位元变换来处理剩余的量子涨落。我们通过直接与数值解的比较来验证我们的方法,重点研究非共振区域,其中多个频移产生丰富的干涉效应和多时间尺度动力学,这些无法被标准近似方法所访问。该方法在相关时间尺度上准确再现了原子翻转、场可观测量和保真度,同时保持计算效率。

英文摘要

We study a two-level system coupled to two quantized electromagnetic modes within the Jaynes-Cummings framework. While the single-mode model is exactly solvable due to its conserved excitation number, yielding finite-dimensional invariant subspaces, the two-mode model extension presents a fundamental challenge: although the total excitation number remains conserved, each invariant subspace is infinite-dimensional, preventing a closed-form analytical solution. Our scheme separates the dynamics into a dominant, exactly solvable semiclassical component, the atom interacting with the mean fields of both modes, and treats the remaining quantum fluctuations through a sequence of unitary transformations that preserve essential quantum features. We validate our approach through direct comparison with numerical solutions, focusing on the non-resonant regime where multiple detunings give rise to rich interference effects and multi-timescale dynamics inaccessible to standard approximations. The method accurately reproduces atomic inversion, field observables, and fidelity over relevant timescales, while remaining computationally efficient.

2605.20154 2026-05-21 stat.ME stat.AP

Component over Composite: Mitigating Type I Error Inflation when Imputing "Days Alive and at Home"

组件与复合体:在填补“在家存活天数”时减轻I型错误膨胀

Mia S. Tackney, Sarah Dawson, Letao Yuan, Dominique-Laurent Couturier, Sofia S. Villar

AI总结 本文研究了在填补“在家存活天数”复合结局时如何减轻I型错误膨胀的问题,通过模拟研究比较了不同处理缺失数据的方法,发现对组件层面进行多重插补比对复合体层面进行插补更能控制I型错误,建议未来研究应开发更适用于复杂DAH定义的插补方法。

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AI中文摘要

背景:在家存活天数(DAH)是在预定义随访期内的一个新型干预后复合结局,结合了至少三个组成部分的数据:(i)初始住院天数,(ii)总再住院或其他出院后护理的天数,(iii)死亡率。缺失值给分析DAH结局的试验带来了独特挑战,因为三个组成部分可能有不同的缺失率,由于不同的缺失数据机制。当前方法将DAH定义为缺失如果任何组成部分缺失,并进行完整案例分析或复合物的多重插补(MI)。方法:通过受NOTACS试验启发的模拟研究,我们比较了几种处理缺失数据的方法,包括完整案例分析、复合物的MI,以及在主要分析为曼-惠特尼-威尔科克森检验时对组件进行MI。结果:对组件层面进行MI在I型错误控制和功效方面有良好的特性。我们警告不要使用预测均值匹配(PMM)对复合体层面进行MI,这可能导致I型错误膨胀。结论:鉴于DAH的复杂分布特征,将缺失性定义在复合体层面并直接使用PMM插补复合体的简单方法可能导致I型错误膨胀。建议对组件层面进行插补,未来研究应包括开发适用于更复杂DAH定义的插补方法,以及对“缺失于随机”假设的敏感性分析建议。

英文摘要

Background: Days Alive and at Home (DAH) over a pre-defined follow-up period is a novel post-intervention composite outcome that combines data from at least three components: (i) initial length of hospital stay, (ii) length of total readmissions or other post-discharge care and (iii) mortality. Missing values bring unique challenges to the analysis of trials with the DAH outcome as the three components may have different rates of missingness caused by distinct missing data mechanisms. Current approaches define DAH as missing if any of the components are missing, and proceed with complete cases or Multiple Imputation (MI) of the composite. Methods: Through a simulation study motivated by the NOTACS trial, we compare several methods of handling missing data, including complete case analysis, MI of the composite, and MI of the components when the primary analysis is a Mann-Whitney-Wilcoxon test. Results: MI on the component level has good properties in terms of type I error control and power. We caution against the use of MI on the composite level with Predictive Mean Matching, which can lead to type I error inflation. Conclusions: Given the complex distributional characteristics of DAH, naive approaches such as defining missingness on the composite level and directly imputing the composite with Predictive Mean Matching, can lead to type I error inflation. Imputing on the component level is recommended, suggested future work included imputation approaches that are compatible with more complex definitions of DAH, as well as recommendations for sensitivity analyses to the Missing at Random assumption.