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2604.28135 2026-05-01 astro-ph.EP

The Influences of Hydrogen-Silicate-Iron Miscibility on the Demographics of Sub-Neptunes and Super-Earths

水-硅酸盐-铁混溶性对亚 Neptune 和超级地球人口学的影响

Edward D. Young, Aaron Werlen

AI总结 研究通过模拟氢、熔融硅酸盐和熔融铁的混溶性及大气逃逸,解释亚 Neptune 和超级地球在质量-半径空间中的分布特征,揭示混溶性对行星形成和演化的影响。

Comments Submitted to ApJ

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AI中文摘要

基于氢、熔融硅酸盐和熔融铁之间可变混溶性以及大气逃逸的模型,能够再现观测到的亚 Neptune 和超级地球在质量-半径空间中的发生密度结构。这些模型还与这些行星表现出的半径间隙和半径-周期关系一致。预测和观测行星发生程度的重叠表明,氢-硅酸盐-铁混溶性可能成为解释这些行星类别的形成和演化的一个统一概念。超临界岩浆海洋与上方富含氢包层之间平衡条件的明确性是模型的重要特征。形成时氢含量低于约1%的行星发展出离散的类地金属核心,而吸积更高氢浓度的行星则被预测具有完全混溶的内部结构和无离散金属核心。氢-硅酸盐-铁混溶性基于吸积的氢质量分数和调控硅酸盐、铁金属和H₂混溶性的相平衡,为亚 Neptune 和超级地球的全部架构提供了全面的解释。

英文摘要

Models based on variable miscibility among hydrogen, molten silicate, and molten iron, coupled with atmospheric escape, can reproduce the observed occurrence density structure of sub-Neptunes and super-Earths in mass-radius space. The models are also consistent with the radius gap and the observed radius-period relationship exhibited by these planets. The degree of overlap between predicted and observed planetary occurrences suggests that hydrogen-silicate-iron miscibility may serve as a unifying concept for the formation and evolution of these planet classes. The well-defined equilibrium conditions at the boundary between supercritical magma oceans and the overlying hydrogen-rich envelopes are important features of the models. Planets formed with less than ~1 % hydrogen by mass develop discrete, terrestrial-like metallic cores, while those accreting greater hydrogen concentrations are predicted to have fully miscible interiors and no discrete metal cores. Hydrogen-silicate-iron miscibility provides an overarching explanation for the full range of sub-Neptune and super-Earth architectures based on the accreted hydrogen mass fraction and the phase equilibria governing silicate, iron metal, and H$_2$ miscibility.

2604.28133 2026-05-01 hep-ex hep-ph

The DAMSA Experiment

DAMSA实验

Prithak Bhattarai, Andrew Brandt, Alan Bross, Bradley Brown, Samriddha Chakraborty, Haohui Che, Bhupal Dev, Bhaskar Dutta, Juan V. Estrada, Eric Garcia, Anthony Gomez, Gajendra Gurung, Brian Joshua Gomez Hernandez, Wooyoung Jang, Jay Hyun Jo, Krzysztof Jodłowski, Doojin Kim, Eunsu Kim, Hyunyong Kim, Shin Hyung Kim, Young-Kee Kim, Jing Liu, Chang-Seong Moon, Donna Naples, David Nygren, Minseok Oh, Vittorio Paolone, Hyangkyu Park, Jong-Chul Park, Nathaniel J. Pastika, Rohit Raut, Juergen Reichenbacher, Paul Rubinov, Eunsuk Seo, Veronika Shalamova, Seodong Shin, Melvin Shochet, Adrian Thompson, Yau Wah, Shawn Westerdale, Guang Yang, Un-Ki Yang, Inseok Yoon, Jaehoon Yu

AI总结 DAMSA实验旨在通过短基线加速器/束流探测器研究短寿命物理过程,探索暗物质领域及标准模型罕见信号,通过紧凑探测器和优化背景抑制技术实现高灵敏度探测。

Comments 35 pages, 26 figures. arXiv admin note: substantial text overlap with arXiv:2601.15255

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AI中文摘要

DAMSA(DArk Messenger Searches at an Accelerator)是一个新型短基线加速器/束流探测器实验,旨在探测短寿命物理过程,包括寻找暗物质领域证据及标准模型罕见信号。受中微子物理问题和传统弱相互作用大质量粒子缺乏确凿证据的启发,DAMSA目标探测MeV至亚GeV的暗物质使者,这些粒子可通过束流/靶产生。通过超短基线,DAMSA能克服长基线实验受限的束流探测“天花板”。概念设计强调束流产生方案与紧凑探测器结合,优化罕见衰变探测同时抑制高功率质子束引起的强烈中子背景。为验证实验策略和探测器技术,提出DAMSA路径先行者(DPF)概念验证实验,聚焦于衰变为两光子的轴子类粒子,使用8GeV电子束在SLAC Linac-to-ESA(LESA)设施运行。DPF的成功将验证DAMSA方法的可行性,推动探索短寿命新物理和标准模型精密过程的广泛有力计划。本文概述了DAMSA的物理目标、关键实验挑战及解决方案。

英文摘要

DAMSA (DArk Messenger Searches at an Accelerator) is a novel short-baseline accelerator/beam dump experiment aimed at probing short-lived physics processes, including searches for evidence of a dark sector of particle physics and well-motivated rare Standard Model signals. Motivated by open questions in neutrino physics and the absence of conclusive evidence for conventional weakly interacting massive particles, DAMSA targets MeV-to-sub-GeV dark-sector messengers with feeble couplings that can be produced in abundance at a beam dump/target. By employing an ultra-short baseline, DAMSA is uniquely positioned to overcome the beam-dump "ceiling" that limits sensitivity to fast decaying particles in longer-baseline experiments. The conceptual design emphasizes a beam-dump production scheme combined with a compact detector optimized for rare decays while mitigating intense neutron-induced backgrounds, inherent to high-power proton beams. To validate the experimental strategy and detector technologies, the DAMSA Path-Finder (DPF) proof-of-concept experiment is also proposed, focusing on axion-like particles decaying to two photons, as the benchmark physics case and operating with 8 GeV electron beams at SLAC Linac-to-ESA (LESA) facility. Successful realization of DPF will establish the feasibility of the DAMSA approach, enabling a broad and powerful program to explore short-lived new physics and precision Standard Model processes in a previously inaccessible regime. This paper outlines the technical details of DAMSA's physics goals, key experimental challenges, and how to overcome them.

2604.28132 2026-05-01 astro-ph.CO astro-ph.GA gr-qc

Finding the one: identifying the host of compact binary mergers

寻找唯一一个:确定致密双星并合的宿主

Alberto Salvarese, Hsin-Yu Chen, Daniel E. Holz

AI总结 通过电磁观测确定致密双星并合的宿主星系,有助于研究其形成历史和测量宇宙学参数。本文基于LVK网络的定位体积和星系亮度,估计各事件对应的哈勃常数,并发现仅少数星系可能与并合事件相关。

Comments 11 pages, 3 figures, 3 tables. Comments are welcome

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AI中文摘要

确定恒星质量致密双星并合的宿主星系将为研究其形成历史和测量关键宇宙学参数,如哈勃常数,开辟新窗口。迄今为止,只有GW170817的宿主星系通过电磁对应观测得以确认。由于LVK网络的定位体积大以及大多数事件缺乏电磁辐射,宿主识别具有挑战性。然而,随着引力波探测器网络灵敏度的提高,事件定位变得越来越精确。此外,星系亮度与质量或恒星形成率相关,因此与并合宿主的概率相关。聚焦于最佳定位事件的定位体积中最亮的星系,通过结合其红移和由LVK观测推断的视距,估计每个星系的哈勃常数。对于最精确定位的LVK事件S250207bg、GW190814和S250830bp,我们发现分别只有1、1和4个星系,当限制分析到每个事件定位体积中最亮的1%的星系(亮度高于约10^{11} h^{-2} L_\odot)并采用广义的H_0先验时。这些星系与GW事件随机关联的概率为29-36%。我们鼓励对这些候选宿主星系进行进一步观测。我们预计这种方法在未来LVK观测运行中将变得越来越强大,能够对并合形成历史进行约束并测量哈勃常数。

英文摘要

Finding the host galaxies of stellar-mass compact binary mergers will open a new window for studying their formation histories and measuring key cosmological parameters, such as the Hubble constant. To date, only one merger, GW170817, has had its host galaxy confidently identified through electromagnetic counterpart observations. The large localization volumes from the LIGO-Virgo-KAGRA (LVK) network, combined with the lack of electromagnetic emission for most events, make host identification challenging. However, as the sensitivity of the gravitational-wave (GW) detector network improves, events are becoming increasingly well localized. Furthermore, galaxy luminosity traces mass or star formation rate, and thus correlates with the probability of hosting a merger. Focusing on the most luminous galaxies within the localization volumes of the best-localized GW events, we estimate the corresponding Hubble constant for each galaxy by combining its redshift with the luminosity distance inferred from LVK observations. For the well-localized LVK events \texttt{S250207bg}, \texttt{GW190814}, and \texttt{S250830bp}, we find only $1$, $1$, and $4$ galaxies, respectively, when restricting the analysis to the most luminous $1\%$ of galaxies above $L_{\rm th} \sim 10^{11} h^{-2} L_{\odot}$ in each event's localization volume and adopting a broad $H_0$ prior. The probability of these galaxies being random, and not associated with the GW events, is $29$-$36\%$ across the three events. We encourage further follow-up observations of these candidate host galaxies. We expect this approach to become increasingly powerful in future LVK observing runs, enabling constraints on merger formation histories and measurements of the Hubble constant.

2604.28128 2026-05-01 cond-mat.mtrl-sci

Unveiling the potential of NdPO4 magnetocaloric phases in cryogenic refrigeration

揭示NdPO4磁卡效应相在低温制冷中的潜力

M. Balli, L. Attou, S-E. Bouzarmine, S. Oubad, K. El Maalam, P. Fournier, S. Mangin

AI总结 研究通过简单沉淀法合成NdPO4相,发现其在低温磁制冷中具有潜力,展示出约19 J/kg K的磁卡效应,优于含高价稀土元素的参考材料。

Comments Paper presented at Intermag2026, Manchester, UK

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AI中文摘要

RPO4正磷酸盐(R为稀土元素)因其电子、轨道和结构有序参数的强耦合而近期受到广泛关注,导致多种功能特性。本文表明,通过简便的沉淀生长法合成的NdPO4相在低温磁制冷中展现出前景。其结构分析显示纳米棒形貌,直径10-20 nm,长度200-500 nm,热处理将其六方rhabdophane型结构转变为单斜无水monazite型对称。磁化测量和DFT计算显示在2-300 K范围内存在强反铁磁耦合但无磁序。另一方面,NdPO4单斜相在约3 K时5 T下表现出约19 J/kg K的磁卡效应,优于含更昂贵稀土元素的参考材料。

英文摘要

The RPO4 orthophosphates (R = rare earth element) have recently attracted a wide interest due to the strong coupling between their electronic, orbital and structural ordering parameters resulting in a variety of functional properties. Herein, we demonstrate that NdPO4 phases synthesized via a facile precipitation growth process unveil promise in low-temperature magnetic cooling. The analysis of their structural properties reveals nanorod forms with diameters of 10 to 20 nm and lengths ranging from 200 to 500 nm while the heat treatment transforms their hexagonal rhabdophane-type structure to a monoclinic anhydrous monazite-type symmetry. Magnetization measurements and DFT calculations show strong antiferromagnetic couplings and the absence of any magnetic ordering in the 2-300 K range. On the other hand, the monoclinic phase of NdPO4 exhibits a large magnetocaloric effect of about 19 J/kg K under 5 T near 3 K, outperforming some reference materials containing more expensive rare-earth elements with high magnetic moments.

2604.28124 2026-05-01 q-fin.RM

Measuring the risk or reducing it, that is the question: is risk measurement necessary for risk reduction?

衡量风险或减少它,这是个问题:风险测量对于风险减少是必要的吗?

Pierpaolo Uberti

AI总结 本文提出通过矩阵谱分析实现风险减少,无需依赖风险测量,通过识别高风险情景并降低投资敞露来降低风险,实验证明其有效性。

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AI中文摘要

本文从广泛接受的风险定义出发,支持风险减少比风险最小化更现实。通过推广矩阵的数值秩和条件数,提出基于回报矩阵谱分析的方法,直接对有限风险情景排序。通过实验证明,该方法能有效降低风险,同时保持平均收益和夏普比率。

英文摘要

In this research, starting from a widely accepted definition of risk, we support the idea that risk reduction is a more realistic objective than risk minimization, which represents a theoretical utopia. Furthermore, significant risk reduction can be achieved without relying on risk measurement and risk minimization. To this end, we propose a generalization of the numerical rank and the condition number of a matrix, specifically the return matrix in this application. This generalization considers the entire matrix spectrum instead of focusing only on the smallest eigenvalue, as the condition number does. The approach directly provides an order among a finite number of risky scenarios. Risk reduction is obtained by identifying the riskiest scenarios and reducing investment exposures corresponding to them. The validity of this theoretical proposal is supported by a comprehensive experiment performed on real data. The capacity of the proposed approach to effectively reduce risk is proven by measuring the variability of out-of-sample returns for benchmark portfolios-constructed by minimizing standard risk measures-compared to the strategy of reducing exposure in high-risk scenarios. Finally, preventing large losses with limited active management-thereby controlling the impact of transaction costs-not only reduces risk but also preserves the average return and, consequently, the portfolio's Sharpe ratio.

2604.28121 2026-05-01 quant-ph physics.comp-ph

Quantum Lattice Boltzmann Solutions for Transport under 3D Spatially Varying Advection on Trapped Ion Hardware

量子格子玻尔兹曼求解器用于受三维空间变化对流作用的输运问题

Sayonee Ray, Jezer Jojo, Jason Iaconis, Abeynaya Gnanasekaran, Apurva Tiwari, Martin Roetteler, Chris Hill, Jay Pathak

AI总结 本文提出利用量子格子玻尔兹曼方法模拟非均匀速度场下的输运现象,探讨了密度读取与重载的瓶颈问题,并引入了新的壁边界实现方法。

Comments 11 pages, 11 figures

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AI中文摘要

量子格子玻尔兹曼方法(QLBM)已成为计算流体动力学(CFD)数值模拟中最具前景的量子计算方法之一。该方法通过描述由离散玻尔兹曼传输方程支配的宏观粒子分布函数来建模动力学,包括局部流和碰撞操作。在本文中,所得到的宏观行为对应于输运现象的对流-扩散方程,我们将其作为标准模型问题。基于最近的QLBM实现进展,我们朝着更现实的问题设置迈进,以更好地反映传统CFD需求。我们首次在量子硬件上处理非均匀速度场下的输运问题。我们使用IonQ的囚禁离子系统进行演示,包括Forte系列系统和一个64量子比特的钡开发系统,类似于即将推出的IonQ Tempo系列。我们识别出密度读取和随后的流体密度重载是当前算法的潜在瓶颈,并讨论了几种缓解该瓶颈的方法。我们识别出使用MPS影子tomography作为高效扩展读取到大规模系统的方法。最后,我们介绍并模拟了一种新的方法,用于在QLBM中实现壁边界,讨论了扩展到更高复杂性问题的前景。

英文摘要

The Quantum Lattice Boltzmann Method (QLBM) has emerged as one of the most promising quantum computing approaches for the numerical simulation of problems in computational fluid dynamics (CFD). The dynamics is formulated in terms of mesoscopic particle distribution functions governed by a discrete Boltzmann transport equation, comprising local streaming and collision operations. In this work, the resulting macroscopic behavior corresponds to the advection-diffusion equation, which we adopt as a canonical model problem for transport phenomena. Building upon recent progress in QLBM implementations, we advance towards more realistic problem settings that better reflect conventional CFD requirements. We address, for the first time, transport under the action of non uniform velocity fields on quantum hardware. We implement our demonstration using IonQ's trapped-ion systems including Forte generation systems and a 64-qubit Barium development system similar to the forthcoming IonQ Tempo line. We identify the density readout and subsequent reloading of the fluid density as a potential bottleneck of the current algorithm and discuss several approaches to mitigate this bottleneck. We identify the use of MPS shadow tomography as a promising method to efficiently scale the readout to large system with complex density distributions. Lastly, we introduce and simulate a novel method to implement wall boundaries for advection-diffusion in QLBM, and discuss the prospects of scaling to higher-complexity problems.

2604.28120 2026-05-01 cond-mat.mtrl-sci

Polar Topologies in a Ferroelastic Metal Membrane

铁电金属膜中的极性拓扑

Rahil Haria, Noah Schnitzer, T. Ben Britton, Yaqi Li, Tom J. P. Irons, Sophia Linssen Pitsaros, Ella Banyas, Geri Topore, Annabel Hoyes, Mariana Palos, Sinead M. Griffin, Katherine Inzani, Michele Shelly Conroy

AI总结 研究通过释放SrRuO3薄膜生成纳米级铁弹性域,发现其自动生成两种极性纹理,揭示了铁弹性壁和应变弹性补偿在极化形成中的作用。

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AI中文摘要

极性金属是兼具电极化和金属性的材料,极为罕见,因为自由电子会屏蔽长程偶极子并倾向于中心对称结构。在导电磁体中工程极性纹理有望实现可重构的自旋轨道耦合和磁电功能。本文展示,从基板剥离的SrRuO3薄膜驱动从微米到纳米尺度的铁弹性域细化,并自发产生两种不同的极性纹理。通过结合mesoscale电子通道成像(ECCI)和原子分辨率扫描透射电镜(STEM)显微镜,证明电极化在翻译非等价反相边界(APBs)中选择性出现。在这些边界,多组分aac倾斜场经历类似Neel的插值,保持同相倾斜成分并放大罗托压电耦合,而翻译等价边界保持非极性。Neel-like插值在硬APBs和Ising-like塌陷在易APBs均被ab initio计算证实。嵌入的90铁弹性墙提供另一种机制不同的极化源,导致极化纳米簇(4 nm)。这些发现表明,在膜状结构中,金属氧化物为纳米级铁弹性域提供了稳定的平台,能够生成极性纹理。

英文摘要

Polar metals, materials in which electric polarisation and metallicity coexist, are exceptionally rare because itinerant electrons screen long-range dipoles and favour centrosymmetric structures. Engineering polar textures in a conducting magnet holds promise for reconfigurable spin orbit coupling and magnetoelectric functionality. Here we show that releasing epitaxial SrRuO3 films from their substrates drives a hierarchy of ferroelastic domain refinement from micrometre to nanometre length scales, and that this structural reorganisation spontaneously generates two distinct classes of emergent polar texture that are ubiquitous across the freestanding membrane. Using correlative microscopy from mesoscale electron channelling contrast imaging (ECCI) to atomic resolution scanning transmission electron microscopy (STEM), we demonstrate that electric polarisation emerges selectively at translation-inequivalent antiphase boundaries (APBs). At these boundaries multicomponent aac tilt field undergoes Neel-like interpolation that preserves the in-phase tilt component and amplifies roto flexoelectric coupling, while translation-equivalent boundaries remain nonpolar. The Neel like interpolation at hard APBs and Ising like collapse of all tilt components at easy APBs is corroborated with ab initio calculations. While embedded 90 ferroelastic walls provide an additional mechanistically distinct source of electric polarisation resulting in polar nanoclusters (4 nm). These distinct nanotextures at 90 walls from via elastic accommodation of strain mismatch between variants and rotostriction as the tilt field interpolates across the boundaries. These findings show that, in a membrane form, metal oxides provide a robust platform for hosting nanoscale ferroelastic domains that generate polar textures.

2604.28117 2026-05-01 cond-mat.stat-mech

Strong Mpemba Effect Through a Reentrant Phase Transition

强Mpemba效应通过重新进入相变

Kristian Blom, Doron Benyamin, Uwe Thiele, Oren Raz, Aljaz Godec

AI总结 研究发现,在抗铁磁伊辛模型中,通过重新进入相变的温度淬火可产生强直接和逆Mpemba效应,其源于对最慢松弛模式的选择性激发,且在顺磁相中该模式为纯阶梯状。

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AI中文摘要

我们研究了在磁场中抗铁磁伊辛模型重新进入相变的温度淬火,并展示当淬火终止于顺磁相时,强直接和逆Mpemba效应出现。这些异常松弛现象源于对最慢松弛模式的选择性激发,该模式在顺磁相中为纯阶梯状。因此,从顺磁相开始的淬火与最慢模式无重叠,表现出强(逆)Mpemba效应。从抗铁磁相开始的淬火激发阶梯模式并显示慢松弛尾。通过改变晶格配位数,我们展示在无重新进入的情况下,强Mpemba效应消失。我们的结果提供了基于配对近似的第一项证明,展示了强(逆)Mpemba效应在抗铁磁伊辛模型中的表现,并建立了异常松弛与平衡相行为之间的联系。

英文摘要

We investigate temperature quenches across the reentrant phase transition of the antiferromagnetic Ising model in a magnetic field and show that the strong direct and inverse Mpemba effects arise when quenches terminate in the paramagnetic phase. These anomalous relaxation phenomena originate from the selective excitation of the slowest relaxation mode, which in the paramagnetic phase is purely staggered. Consequently, quenches starting from the paramagnetic phase have zero overlap with the slow mode and exhibit a strong (inverse) Mpemba effect. Quenches from the antiferromagnetic phase excite the staggered mode and display a slow-relaxation tail. By varying the lattice coordination number we show that the strong Mpemba effect disappears in the absence of reentrance. Our results provide the first demonstration of the strong (inverse) Mpemba effect in the antiferromagnetic Ising model based on the pair-approximation, and establish a link between anomalous relaxation and the equilibrium phase behavior.

2604.28116 2026-05-01 math.CO math.NT math.PR

The proportion of permutations fixing a $k$-set

固定k集的排列比例

Ben Green, Mehtaab Sawhney

AI总结 研究随机排列中固定k集的概率,推导出渐近公式,揭示其与k的函数关系及常数δ的计算,为乘法表中不同元素数量估计提供模型。

Comments 116 pages

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AI中文摘要

设p(k)为当n趋近于无穷时,随机排列在大小为n的集合上具有大小为k的不变集的概率极限。本文给出了p(k)的渐近公式,显示其渐近为f({log₂k})k^{−δ}(logk)^{−3/2},其中δ=1−(1+loglog2)/log2≈0.086,f是实数域上光滑正函数。我们推测f并非常数。估计p(k)是估计n×n乘法表中不同元素数量问题的模型。通过本文技术,后续工作将给出M(n)的渐近公式。

英文摘要

Denote by $p(k)$ the limit, as $n \rightarrow \infty$, of the probability that a random permutation on a set of size $n$ has an invariant set of size $k$. We give an asymptotic formula for $p(k)$, showing that it is asymptotically $f(\{\log_2 k\}) k^{-δ} (\log k)^{-3/2}$ where $δ= 1 - \frac{1 + \log \log 2}{\log 2} \approx 0.086$ and $f$ is a smooth, positive, function on $\mathbb{R}/\mathbb{Z}$, which we will describe explicitly. The function $f$ satisfies $\frac{\max f}{\min f} < 1 + 2 \times 10^{-7}$ and we conjecture that it is not constant. Estimating $p(k)$ is a model for the more well-known question which asks for an estimation of $M(n)$, the number of distinct elements in the $n$-by-$n$ multiplication table. By elaborating on the techniques in this paper, we will give an asymptotic for $M(n)$ in forthcoming work.

2604.28114 2026-05-01 hep-th math-ph math.MP

BV quantization of $ϕ^3$-theory on $λ$-Minkowski space: Tree-level correlation functions

$ϕ^3$-理论在$λ$-Minkowski空间中的BV量化:树级关联函数

Djordje Bogdanović, Marija Dimitrijević Ćirić, Stefan Djordjević, Richard J. Szabo

AI总结 本文比较了标准和编织BV量化方案在$ϕ^3$-理论中树级三点和四点关联函数的差异,揭示了非交换贡献的不同表现形式。

Comments 16 pages; Contribution to the Proceedings of the Corfu Summer Institute 2025 "School and Workshops on Elementary Particle Physics and Gravity'' (CORFU2025), 27 April-28 September 2025, Corfu, Greece

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AI中文摘要

本文回顾了使用Batalin--Vilkovisky (BV) 公式对λ-Minkowski空间上的标量场理论进行量子化。我们考虑了ϕ³理论在两种不同的量子化方案中:标准和编织。尽管标准BV量子化基于普通的L∞-代数,编织BV量子化则基于编织的L∞-代数。我们比较了两种方法在树级三点和四点关联函数中的差异。对于四点函数,标准量子化导致两种不等价的图类,具有不同的非交换贡献,而编织量子化则仅产生一个图类,非交换性仅通过外部动量的总体相位因子进入。

英文摘要

We review the quantization of scalar field theory on $λ$-Minkowski space using the Batalin--Vilkovisky (BV) formalism. We consider $ϕ^3$-theory in two different quantization schemes: standard and braided. While standard BV quantization is based on an ordinary $L_\infty$-algebra, braided BV quantization is based on a braided $L_\infty$-algebra. We compare the tree-level three-point and four-point correlation functions in the two approaches. For the four-point function, standard quantization leads to two inequivalent classes of diagrams with different noncommutative contributions, whereas braided quantization yields only a single class of diagrams with noncommutativity entering solely through an overall phase factor depending on the external momenta.

2604.28110 2026-05-01 math.OC math.FA

A Scaled Gradient Modified Non-monotone Line Search Method for Constrained Optimization Problems

一种用于约束优化问题的缩放梯度修改非单调线搜索方法

Qamrul Hasan Ansari, Feeroz Babu, D. R. Sahu, Jen Chih Yao

AI总结 本文提出一种缩放梯度修改非单调线搜索方法,用于求解约束最小化问题,并探讨其收敛性,针对强拟凸目标函数证明线性收敛性,通过大规模分数规划和二次规划数值实验验证方法性能。

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AI中文摘要

本文提出了一种缩放梯度修改非单调线搜索方法,用于求解约束最小化问题,并探讨了该方法的若干具体性质,即收敛性分析。我们讨论了所提出算法生成的序列对强拟凸目标函数的约束最小化问题的线性收敛率。我们考虑了大规模分数规划和二次规划中的函数,这些函数是伪凸和强拟凸的,并将所提算法与现有算法在这些示例中的性能进行了比较。

英文摘要

In this paper, we propose a scaled gradient modified non-monotone line search method for solving constrained minimization problems, and explore several specific properties of this method, namely, its convergence analysis. We discuss the linear convergence rate of the sequence generated by the proposed algorithm to a solution of the constrained minimization problem where the objective function is strongly quasiconvex. We consider numerical examples of large-scale fractional programming and quadratic programming for the function of pseudo convex and strongly quasiconvex and compare the performance of the proposed algorithm with the existing ones for these examples.

2604.28108 2026-05-01 eess.SY cs.SY

Hierarchical Control for Continuous-time Systems via General Approximate Alternating Simulation Relations

基于通用近似交替模拟关系的连续时间系统分层控制

Zhiyuan Huang, Shuo Li, Murat Arcak, Majid Zamani, Bingzhuo Zhong

AI总结 本文提出了一种适用于连续时间系统的通用近似交替模拟关系,用于容忍抽象与具体模型之间的较大差异,并开发了控制细化方法以实现分层控制,通过案例研究验证了其有效性。

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AI中文摘要

本文提出了一种适用于连续时间系统的通用近似交替模拟关系,用于容忍抽象与具体模型之间的较大差异,并开发了控制细化方法以实现分层控制,通过案例研究验证了其有效性。

英文摘要

This paper introduces a general approximate alternating simulation relation (\emph{$\varepsilon$-gAAS relation}) for continuous-time systems, which relaxes existing simulation relations to tolerate larger mismatches between abstract and concrete models. The definition of gAAS for continuous-time systems is first proposed, and its properties are investigated. Then, a control refinement method is developed to enable hierarchical control for the gAAS relation. Finally, case studies demonstrate the effectiveness of the proposed approach, highlighting its advantages over existing methods.

2604.28106 2026-05-01 cond-mat.mtrl-sci physics.chem-ph

Machine Learning and Molecular Simulations Reveal Mechanisms of ZIFs Polymorph Selection

机器学习与分子模拟揭示ZIFs多形体选择机制

Emilio Méndez, Rocio Semino

AI总结 通过机器学习与分子模拟研究ZIFs多形体选择机制,发现预成核簇和非晶中间体结构对最终多形体有决定性影响。

Comments 54 pages, 20 figures, 4 tables

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AI中文摘要

Zn(imidazolate)₂金属有机框架(MOFs)表现出显著的多形性。由于其工业应用前景,许多研究小组已研究了这些多形体的相变、相图和相对稳定性。目前研究界普遍认为这些MOFs通过非经典成核机制溶热合成,其中首先形成预成核簇,随后形成中间非晶结构,最终重新组织为最终晶体MOF。然而,迄今为止尚无研究揭示合成过程中哪一部分决定了最终获得的多形体。在本工作中,使用部分反应力场进行路径集体变量元动力学模拟,为这些MOFs的自组装机制和热力学方面提供了见解。从模拟中构建了瞬态和中间合成结构数据库。通过开发和应用神经网络分类器对这些数据库进行分析,发现预成核簇和非晶中间体结构均具有多形依赖性。这些结果表明,多形体选择在预成核簇阶段就已经发生。

英文摘要

Zn(imidazolate)$_2$ metal-organic frameworks (MOFs) exhibit a remarkable degree of polymorphism. Because of their promising industrial applications, many research groups have investigated phase transitions, phase diagram and relative stability of these polymorphs. There is now wide consensus in the research community that these MOFs are solvothermally formed via non-classical nucleation mechanisms, in which pre-nucleation clusters are first formed, followed by an intermediate amorphous structure that subsequently reorganizes to yield the final crystalline MOF. However, no study up to date has uncovered which part of the synthesis process determines the final polymorph obtained. In this work, path collective variable metadynamics simulations performed with a partially reactive force field give insights into mechanistic and thermodynamic aspects of the self-assembly of these MOFs. Databases of transient and intermediate synthesis structures are built from the simulations. By developing and applying neural network classifiers over these databases, it is found that both pre-nucleation clusters and the amorphous intermediate structures are polymorph-dependent. These results suggest that polymorph selection happens as early as the pre-nucleation cluster stage.

2604.28105 2026-05-01 cond-mat.mtrl-sci cond-mat.other

From Narrow-gap Semiconductor to Metallic Altermagnet: Optical Fingerprints of Co-Doped FeSb$_2$

从窄带半导体到金属阿尔特磁体:Co掺杂FeSb₂的光学指纹

R. Mathew Roy, M. Povolotskiy, J. Kirschke, C. Prange, Y. Xia, V. Sundaramurthy, P. Puphal, M. Pinteric, M. van de Loo, A. Kreyssig, T. Zhang, A. E. Böhmer, M. Dressel, M. Wenzel

AI总结 研究通过Co掺杂使FeSb₂从窄带半导体转变为金属阿尔特磁体,揭示了低能能级跃迁与自旋有序的关系,为探索金属d波阿尔特磁体提供了新平台。

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AI中文摘要

尽管候选材料不断增多,但实现体态金属阿尔特磁性仍具挑战性。本文证明适度的钴掺杂(约15%)将相关窄带半导体FeSb₂驱动至在室温下持续存在的金属阿尔特磁态。近红外光学电导显示低能 interband 跃迁在0.1 eV附近出现并随Co浓度增加而增强。密度泛函理论计算表明这些跃迁仅源于阿尔特磁自旋有序,非相对论性自旋分裂带(约0.2 meV)与自旋轨道耦合引起的费米能级附近带分裂(约5 meV)共同作用。Co掺杂进一步导致近红外活性声子的Fano线形和模式混合,反映增强的电子-声子耦合和局部反演对称性破坏,同时保持阿尔特磁自旋对称性。本研究确立了可调载流子的FeSb₂作为探索金属d波阿尔特磁性和其与晶格自由度耦合的平台。

英文摘要

The realization of bulk metallic altermagnetism has remained elusive despite the growing number of candidate materials. Here, we present evidence that moderate cobalt substitution ($\sim$15%) drives the correlated narrow-gap semiconductor FeSb$_2$ into a metallic altermagnetic state persisting up to room temperature. The infrared optical conductivity reveals low-energy interband transitions near 0.1 eV that emerge upon doping and grow with Co concentration. Density functional theory calculations show that these transitions originate exclusively from altermagnetic spin ordering, with spin split bands ($\sim$0.2 meV) of non-relativistic origin, together with spin-orbit coupling induced band splitting of the order of $\sim$5 meV near the Fermi level. Co substitution further leads to Fano lineshapes and mode mixing in the infrared-active phonons, reflecting enhanced electron-phonon coupling and local inversion symmetry breaking, while leaving the altermagnetic spin symmetry intact. Our results establish carrier-tuned FeSb$_2$ as a platform for exploring metallic $d$-wave altermagnetism and its coupling to lattice degrees of freedom.

2604.28104 2026-05-01 stat.ME math.ST stat.TH

Kernel-based independence and mean independence tests for weakly dependent data

基于核的方法的弱相关数据独立性与均值独立性检验

Daniel Diz-Castro, Manuel Febrero-Bande, Wenceslao González-Manteiga

AI总结 本文提出了一种统一的框架,用于基于希尔伯特-施密特独立性准则的独立性和均值独立性检验,并在一般拓扑空间中扩展了先前的结果。

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AI中文摘要

我们提供了一个基于希尔伯特-施密特独立性准则的独立性和均值独立性检验的统一框架,将一些文献中的先前结果扩展到一般拓扑空间中。我们还对测试统计量的渐近行为进行了完整的理论分析,当观测样本对应于某些平稳和遍历随机过程的部分样本路径时,假设接近时间依赖性。特别地,我们探讨了在固定假设和局部假设下测试统计量的一致性和极限分布。通过简洁的模拟研究,展示了测试统计量的有限样本性能,涉及功能数据。

英文摘要

We provide a unified framework for independence and mean independence tests based on the Hilbert-Schmidt independence criterion, extending some previous results in the literature to hold in general topological spaces. We also present a complete theoretical analysis of the test statistic asymptotic behavior when the observed sample corresponds to a partial sample path of some stationary and ergodic stochastic process under near epoch dependence assumptions. In particular, we explore the test statistic consistency and limit distribution under both fixed and local hypothesis. The finite sample performance of the test(s) is illustrated with a succinct simulation study involving functional data.

2604.28103 2026-05-01 math.NA cs.NA

Bounded, Commuting, Discrete-trace Preserving Projections

有界、交换、离散迹保持的投影

Alexandre Ern, Johnny Guzmán, Pratyush Potu

AI总结 本文提出了一种有界、交换且保持迹的投影,用于三维de Rham复形,该投影在适当迹空间中保持函数/场的迹。投影在局部定义且在图范数下稳定,应用于构造稳定的分段多项式数据提升及离散与连续扩展的最优性结果。

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AI中文摘要

我们构建了具有有界性和交换性的投影,用于三维de Rham复形,并具有额外性质:当函数/场在适当迹空间中为分段多项式时,投影保持其迹。这些投影局部定义且在图范数下稳定。更具体地说,图范数中涉及外导数的部分仅涉及在紧邻边界的一小带元素中该导数的振荡,并以局部网格尺寸加权。此外,当作用于外导数在适当空间中为分段多项式函数/场时,投影在L²范数下局部稳定。本文展示了这两种有界、交换、离散迹保持投影的两个显著应用:构造稳定的分段多项式数据提升及离散与连续扩展的最优性结果。

英文摘要

We construct bounded, commuting projections for the three-dimensional de Rham complex with the additional property that the projections preserve the trace of functions/fields if the latter is a piecewise polynomial in the appropriate trace space. The projections are locally defined and stable in the graph norm. More precisely, the part of the graph norm involving the exterior derivative only involves the oscillation of this derivative in a narrow strip of elements touching the boundary and weighted by the local mesh size. Moreover, the projections are $L^2$-stable locally when acting on functions/fields whose exterior derivative is a piecewise polynomial in the appropriate space. We present two salient applications of the present bounded, commuting, discrete-trace preserving projections: the construction of stable liftings of piecewise polynomial data and an optimality result on the discrete versus continuous extension of piecewise polynomial data.

2604.28101 2026-05-01 cs.SE

Beyond Code, We Are People: A Systematic Mapping of 25 Years of Literature on Soft Skills in Agile Development Teams

超越代码,我们是人:25年敏捷开发团队软技能文献的系统映射

Israely Lima, Lucas Moura Lourenço, Márcio Ribeiro, Ivan Machado, Carla Ilane Bezerra

AI总结 本研究系统梳理了25年间敏捷开发团队中关键软技能,揭示了沟通、适应力等核心能力及其在不同角色中的关联,指出现有文献在角色特定软技能研究上的不足。

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AI中文摘要

软件开发是一种社会技术与以人为本的 endeavor,其中人类因素直接影响质量、生产力和创新能力。在这一背景下,计算领域的职业发展超越技术精通,要求专业人员具备应对持续变化和协作需求的能力。其中,非技术技能(软技能)尤为突出,涵盖社交、情感和沟通维度,对团队效能和软件项目成功至关重要。尽管其重要性已被认可,但过去25年间对最相关软技能的系统映射仍需进一步研究,这一时期标志着敏捷方法在工业中的广泛应用。本研究通过分析2000年1月至2025年5月期间发表的97篇文献,识别出反复出现的能力如沟通、适应力、团队合作和领导力,以及这些能力在不同敏捷角色中的关联。主要采用的敏捷方法,特别是Scrum,也被识别出来,同时指出现有文献中的关键空白,如对角色特定软技能研究的缺乏。这些发现可支持研究人员、教育者和实践者设计课程、培训策略和组织实践,以符合人类因素,强化在协作和创新专业人员发展中的社会和技术维度的整合。

英文摘要

Software development is a sociotechnical and human-centered endeavor in which human factors directly influence quality, productivity, and innovation capacity. In this context, career development in computing goes beyond technical mastery, requiring competencies that enable professionals to deal with continuous change and collaborative demands. Among these, non-technical skills (soft skills) stand out, encompassing social, emotional, and communicational dimensions essential to team effectiveness and the success of software projects. Despite their recognized importance, there is still a need for a systematic mapping of the most relevant soft skills over the past 25 years, a period marked by the adoption of agile approaches in industry. This gap limits the integration of human and technical aspects in software development. This study presents a systematic mapping of the literature, analyzing 97 studies published between January 2000 and May 2025 across major scientific databases. The results identify recurring competencies such as communication, adaptability, teamwork, and leadership, as well as their association with different roles in agile contexts. The main agile approaches adopted, particularly Scrum, are also identified, along with key gaps in the literature, such as the lack of studies on role specific soft skills. The findings can support researchers, educators, and practitioners in designing curricula, training strategies, and organizational practices aligned with human factors, reinforcing the importance of integrating social and technical dimensions in the development of collaborative and innovative professionals.

2604.28100 2026-05-01 cond-mat.mtrl-sci physics.app-ph physics.chem-ph

Radio Frequency Field-Induced Enhancement of Detection Sensitivity in Silicon Nanowire Sensors

射频场诱导的硅纳米线传感器检测灵敏度增强

Ang Liu, Jingsong Shang, Jiangang J. Du, Shyamsunder Erramilli, Pritiraj Mohanty

AI总结 本研究通过硅纳米线场效应晶体管中的屈折电共振机制,利用射频场诱导应变梯度,提升生物分子结合表面电荷变化的检测灵敏度,实现检测灵敏度提升一个数量级。

Comments 32 pages, 7 figures

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AI中文摘要

在生理液体中敏感生物标记物的检测常受限于德拜屏蔽,它抑制传感器表面的静电信号。本文报道了一种基于硅纳米线场效应晶体管中屈折电共振的传感方法。施加的射频场在纳米线中诱导应变梯度,产生屈折电极化,其在共振频率下被放大。这种效应增强了电导测量对小表面电荷变化的灵敏度。以C反应蛋白为模型生物标记物,我们观察到与传统操作相比,检测灵敏度提高了一个数量级,与射频调制相比,电导增加了62%,而无射频调制时为30%。高频场还扰动了电双层,减少了高离子强度环境中的德拜屏蔽。这些综合效应使无需样品稀释即可直接检测生物标记物。本工作确立了屈折电共振作为在生理相关条件下提高纳米级生物传感性能的一般策略。

英文摘要

Sensitive biomarker detection in physiological fluids is often limited by Debye screening, which suppresses electrostatic signals at sensor surfaces. Here we report a sensing approach based on flexoelectric resonance in silicon nanowire field-effect transistors. An applied radiofrequency field induces strain gradients in the nanowires, generating flexoelectric polarization that is amplified at resonant frequencies. This effect enhances the sensitivity of conductance measurements to small surface charge variations associated with biomolecular binding. Using C-reactive protein as a model biomarker, we observe an order-of-magnitude improvement in detection sensitivity compared to conventional operation, with a 62% conductance increase versus 30% without radiofrequency modulation. The high-frequency field also perturbs the electrical double layer, reducing Debye screening in high-ionic-strength environments. These combined effects enable direct biomarker detection without sample dilution. This work establishes flexoelectric resonance as a general strategy for improving nanoscale biosensing performance in physiologically relevant conditions.

2604.28099 2026-05-01 cond-mat.mtrl-sci

Yukawa screening derivation of the bond-valence rule

Yukawa screening导出的键价规则

Michael L. Whittaker, Pan Wang, Chunhui Li, Naman Katyal, Piotr Zarzycki

AI总结 通过Yukawa筛选理论导出键价规则,揭示其与离子电荷和配位数的关系,并验证其在多种氧化物中的准确性。

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AI中文摘要

键价模型是估算晶体键强的标准方法,但其对键长的指数依赖性缺乏具体物理相互作用的推导。本文显示,这种形式出现在屏蔽库仑静电学的主导项中,并且拟合的键价软度可以解释为电子屏蔽长度。这将键价从经验拟合规则转变为可转移的局部屏蔽电荷响应描述。所提出的理论预测了键价参数如何随离子电荷和配位数变化,并与150个拟合的价态相符,包括68个四配位和82个六配位的阳离子-氧物种,其加权系数决定性为0.986。与第一性原理电荷密度的比较显示,键价壳层半径与电子屏蔽云一致,系数决定性分别为十种碱土氧化物的0.9998和21种其他二元氧化物的0.967。因此,广泛使用的键价模型是离子固体中屏蔽静电学的主导表达式。

英文摘要

The bond-valence model is a standard way to estimate bond strengths in crystals, but its exponential dependence on bond length has lacked a derivation from a specific physical interaction. We show that this form emerges as the leading-order limit of screened Coulomb electrostatics and that the fitted bond-valence softness can be interpreted in terms of an electronic screening length. This turns bond valence from an empirical fitting rule into a transferable descriptor of local screened charge response across coordination environments. The resulting theory predicts how the bond-valence parameters should vary with ionic charge and coordination number, and that prediction agrees with 150 fitted valences from 94 cation-oxygen species, including 68 in fourfold coordination and 82 in sixfold coordination, at an abundance-weighted coefficient of determination of 0.986. A comparison with first-principles charge densities shows that the bond-valence shell radius tracks the electronic screening cloud with coefficients of determination of 0.9998 for ten alkali and alkaline-earth oxides and 0.967 for 21 other binary oxides whose nearest-neighbor environments match the theory's assumptions. The widely used bond-valence model is thus the leading-order expression of screened electrostatics in ionic solids.

2604.28097 2026-05-01 hep-ph astro-ph.CO gr-qc

New gravitational-wave templates for metastable cosmic strings: Loop breaking versus network collapse

稳定的宇宙弦的新引力波模板:环破裂与网络崩溃

Doa Hashemi Asl, Kai Schmitz

AI总结 本文研究了稳定宇宙弦的引力波背景,区分环破裂和网络崩溃的时间尺度,提出三参数模型统一了标准和准稳定弦的建模。

Comments 17 pages, 4 figures, 2 time scales

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AI中文摘要

本文研究了稳定宇宙弦的引力波背景,区分环破裂和网络崩溃的时间尺度,提出三参数模型统一了标准和准稳定弦的建模。

英文摘要

Metastable cosmic strings are a common prediction of grand unified theories and act as a source of a gravitational-wave background (GWB) that can explain the 2023 pulsar timing array (PTA) signal. In this paper, we revisit the GWB signal from metastable strings, emphasizing the need to carefully distinguish between two different time scales: (i) t_LB, the time scale of loop breaking because of spontaneous monopole nucleation on closed string loops, and (ii) t_NC, the time scale of network collapse when string segments attached to monopoles begin to enter the Hubble horizon. We discuss under which conditions these two time scales are similar or far apart from each other and illustrate the resulting consequences for the GWB signal. In doing so, we generalize the description of the GWB signal from metastable strings to a three-parameter model in terms of the string tension Gμand the time scales t_LB and t_NC, which allows us to unify the modeling of standard metastable strings with what is known as quasi-stable strings. In the limit of a large t_LB/t_NC ratio, we, moreover, derive a compact analytical expression for the predicted GWB spectrum in excellent agreement with numerical results in the literature. We thus conclude that our new templates for the GWB spectrum from metastable strings can be readily used in the analysis of future PTA data sets.

2604.28096 2026-05-01 cs.DS

Succinct Graph Representations and Algorithmic Applications

紧凑的图表示及其算法应用

Ahammed Ullah, Alex Pothen

AI总结 本文提出利用密集局部结构的紧凑图表示,改进时间和空间效率。通过定义双团覆盖(DCC)表示,开发了基于该表示的算法,显著提升图算法的性能,如连通分量计算在内存和时间上均取得显著优化。

Comments 53 pages, 26 figures

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AI中文摘要

我们提出了一种新的图表示方法,利用密集的局部结构同时提高时间和空间效率。对于无向图G,我们定义双团覆盖(DCC)表示为(C, L),其中C是覆盖G边的团集合,L是C的 incidence dual。我们识别出可多项式时间构造的DCC表示,称为紧凑DCC表示。然后,我们为几个基本图问题开发了基于表示的算法。我们证明图基本操作如连通分量、广度优先搜索森林、深度优先搜索森林和最大匹配可以按DCC表示的大小而非边数进行计算。结合我们的紧凑DCC表示,这些结果提供了一类算法,其时间和空间界限要么与标准图表示相当,要么更优。此外,我们设计了几种构造紧凑DCC表示的算法,并建立了其效率的可证明保证。我们评估了几种图算法在DCC表示上的性能,与基于邻接表的实现相比,在大量真实世界和合成图上均表现出显著的执行内存节省和总时间加速;例如,连通分量算法平均执行内存节省约9倍,最大达35倍,总时间加速平均约6.5倍,最大达35倍。我们还评估了几种DCC构造算法,发现紧凑性属性在使DCC表示在算法应用中有效方面起关键作用。

英文摘要

We propose new graph representations that exploit dense local structure to improve time and space simultaneously. Given an undirected graph $G$, we define a dual clique cover (DCC) representation of $G$ to be the pair $(C, L)$, where $C$ is a collection of cliques that covers the edges of $G$ and $L$ is the incidence dual of $C$. We identify classes of polynomial-time constructible DCC representations that are compact and call them succinct DCC representations. We then develop representation-aware algorithms for several fundamental graph problems. We show that graph primitives such as connected components, breadth-first search forests, depth-first search forests, and maximal matchings can be computed in time proportional to the size of a DCC representation rather than the number of edges. Combined with our succinct DCC representations, these results give a class of algorithms that either match or improve the time and space bounds of their counterparts on standard graph representations. Furthermore, we design several algorithms for constructing succinct DCC representations and establish provable guarantees on their efficiency. We evaluate several graph algorithms on DCC representations against adjacency-list-based implementations on a large collection of real-world and synthetic graphs. All evaluated applications show substantial execution memory savings and total-time speedups; for example, the connected components algorithm achieves about $9\times$ execution memory savings on average, with a maximum of $35\times$, and about $6.5\times$ total-time speedups on average, with a maximum of $35\times$. We also evaluate several DCC construction algorithms and find that the succinctness property plays a key role in making DCC representations effective for algorithmic applications.

2604.28094 2026-05-01 cond-mat.mtrl-sci

Quantifying Thermal, Photovoltage, and Defect Contributions to Transient Absorption of Ta$_{3}$N$_{5}$ Photoanodes

量化Ta$_{3}$N$_{5}$光阳极瞬时吸收中的热、光电压和缺陷贡献

Johannes Dittloff, Lukas M. Wolz, Matthias U. Quintern, Laura I. Wagner, Matthias Kuhl, Johanna Eichhorn, Ian D. Sharp

AI总结 研究通过结合瞬时吸收光谱与互补光学光谱,解析Ta$_{3}$N$_{5}$中晶格加热、电静力学和缺陷态的贡献,揭示其光电机制。

Comments 30 pages, 5 figures in the main manuscript; 8 pages, 8 figures in the supporting information

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AI中文摘要

Ta$_{3}$N$_{5}$是太阳能水氧化中最广泛研究的光电极材料之一,但其性能常受限于短载流子寿命和缺陷介导的复合。尽管瞬时吸收光谱广泛用于探测光电极载流子动力学,但光谱赋值常因重叠贡献而模糊。本文通过结合微秒到秒的瞬时吸收光谱与互补光学光谱,解析Ta$_{3}$N$_{5}$薄膜中晶格加热、电静力学和缺陷态的贡献。光反射率揭示了Ta$_{3}$N$_{5}$带结构中的三个关键点,包括两个各向异性近边跃迁在2.14 eV和2.27 eV以及一个更高跃迁在2.80 eV,均与主导的瞬时吸收特征紧密对齐。之前未报告的2.80 eV光致吸收归因于泵浦诱导的晶格加热,而电势依赖测量显示近边漂白特征源于泵浦诱导的带展平和随后的表面光电压弛豫。用独立测量的热和电静力学成分拟合瞬时吸收光谱,可以量化热和光电压动态,而子带隙响应提供了缺陷电荷态重新分布的见解。因此,这种量化热、电静力学和缺陷介导贡献的方法为功能性半导体光电极的光电激发和弛豫机制提供了广泛适用的见解。

英文摘要

Ta$_{3}$N$_{5}$ is among the most intensively studied photoanode materials for solar-driven water oxidation, yet its performance often remains limited by short carrier lifetimes and defect mediated recombination. Although transient absorption spectroscopy is widely used to probe carrier dynamics in photoelectrodes, spectral assignments are frequently ambiguous due to overlapping contributions. Here, microsecond-to-second transient absorption of Ta$_{3}$N$_{5}$ thin films is combined with complementary optical spectroscopies to disentangle contributions from lattice heating, electrostatics, and defect states. Photoreflectance reveals three critical points in the Ta$_{3}$N$_{5}$ band structure, including two anisotropic near-edge transitions at 2.14 eV and 2.27 eV and a higher-lying transition near 2.80 eV, all closely aligned with dominant transient absorption features. A previously unreported photo-induced absorption at 2.80 eV is attributed to pump-induced lattice heating, while potential-dependent measurements reveal that near-edge bleach features arise from pump-induced band flattening and subsequent surface photovoltage relaxation. Fitting transient absorption spectra with independently measured thermal and electrostatic components enables quantification of both thermal and photovoltage dynamics, while the sub-bandgap response provides insight into the redistribution of defect charge states. Thus, this approach to quantifying thermal, electrostatic, and defect-mediated contributions to microsecond-to-second transient absorption provides broadly applicable insights into photoexcitation and relaxation mechanisms in functional semiconductor photoelectrodes.

2604.28092 2026-05-01 math.GN

On centered local $π$-bases

关于中心化的局部 π-基

Nathan Carlson

AI总结 本文改进了Hajnal和Juhász的定理,将第一可数性条件替换为更弱的条件,即每个点有可数的中心化局部 π-基,并探讨了其在可数链条件空间中的应用。

Comments 10 pages

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AI中文摘要

1967年,Hajnal和Juhász证明了具有可数链条件的第一可数Hausdorff空间的基数至多为实数的基数c。本文通过将第一可数性条件替换为更弱的条件,即每个点有可数的中心化局部π-基,改进了这一著名定理。给定拓扑空间X中的点p,局部π-基B在p处的行为类似于p处的邻域基,但p可能不在B的任何成员中。如果B的任意有限个成员的交集非空,则称为具有有限交集性质。这种类型的局部π-基称为中心化。中心化的局部π-基在某种意义上更像邻域基。具有可数链条件的空间是指任何两两不相交的开集族都是可数的。本文还利用中心化的局部π-基改进了Pospíšil于1937年的定理。通常,通过例子来展示这些改进是严格的。此外,本文还探讨了紧Hausdorff空间以及中心化局部π-基的变体。

英文摘要

In 1967 Hajnal and Juh{á}sz showed that the cardinality of a first-countable Hausdorff space with the countable chain condition has cardinality at most $\mathfrak{c}$, the cardinality of the real line. We give an improvement of this celebrated theorem by replacing ``first-countable" with the weaker condition ``each point has a countable centered local $π$-base". Given a point $p$ in a topological space $X$, a \emph{local} $π$-\emph{base} $\scr{B}$ at $p$ acts like a neighborhood base at $p$ except that $p$ may not be in any member of $\scr{B}$. A local $π$-base $\scr{B}$ has the \emph{finite intersection property} if any finite intersection of members of $\scr{B}$ is nonempty. We call this type of local $π$-base \emph{centered}. A centered local $π$-base behaves even more like a neighborhood base in a sense. A space has the \emph{countable chain condition} if every family of pairwise disjoint open sets is countable. We also improve a theorem of Pospi{\v s}il from 1937 using centered local $π$-bases. As is customary, examples are given to demonstrate these improvements are strict. Compact Hausdorff spaces are also explored in this connection, along with variations on the notion of a centered local $π$-base.

2604.28091 2026-05-01 cond-mat.mes-hall

Observation of the Magnus Nonlinear Hall effect from Chiral Weyl Monopoles

观测来自手性韦伊尔单极的磁斯非线性霍尔效应

Heda Zhang, Nikolai Peshcherenko, Ning Mao, Nianlong Zou, Jiaqiang Yan, Claudia Felser, Yang Zhang

AI总结 研究通过CoSi材料观测到非线性霍尔效应,揭示了手性韦伊尔节点的拓扑特性,通过非对称散射机制实现了非对称霍尔电压,展示了拓扑非线性霍尔响应的新途径。

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AI中文摘要

非线性霍尔效应(NLHE)将晶格对称性与量子几何联系起来,提供了一种超越线性传输的带拓扑探测方法。尽管大多数研究集中在低对称性晶体中的伯瑞曲率偶极,但针对高对称性手性晶格中伯瑞单极的直接探测机制仍未被探索。在此,我们报告了在手性韦伊尔半金属CoSi中观测到NLHE,该材料中伯瑞曲率偶极被对称性禁止。通过聚焦离子束制备的交叉条器件,我们检测到零磁场下稳健的二次谐波霍尔电压,包含NLHE的所有关键特征。理论分析将非线性霍尔电导归因于自旋转电子波包的非对称散射,其手性由底层带拓扑决定,这一过程类似于经典马格斯效应。此外,NLHE信号表现出温度依赖的符号反转,并且具有强线性磁场依赖的调制,其强度随载流子迁移率增加而增长,直接反映了费米能级附近拓扑韦伊尔节点的分布。这些发现确立了CoSi作为伯瑞单极驱动非线性传输的平台,展示了通过非对称散射实现拓扑非线性霍尔响应的新途径,该途径绕过了传统对称性约束。

英文摘要

The nonlinear Hall effect (NLHE) connects crystalline symmetry to quantum geometry, offering a probe of band topology beyond linear transport. While most studies have focused on the Berry curvature dipole in low-symmetry crystals, mechanisms that directly probe Berry monopoles in higher-symmetry chiral lattices remain unexplored. Here, we report the observations of the NLHE in the chiral Weyl semimetal CoSi, a platform where the Berry curvature dipole is symmetry-forbidden. By employing focused ion beam-fabricated crossbar devices, we detect a robust second-harmonic Hall voltage under zero magnetic field, hosting all key signatures of the NLHE. Theoretical analysis attributes the nonlinear Hall conductivity to skew scattering of self-rotating electron wave packets, whose chirality is dictated by the underlying band topology, a process reminiscent of the classical Magnus effect. Furthermore, the NLHE signal exhibits a temperature-dependent sign reversal, and a strong, linearly field-dependent modulation that grows with carrier mobility, directly reflecting the topological Weyl nodes distribution near the Fermi level. These findings establish CoSi as a platform for Berry monopole-driven nonlinear transport, demonstrating a skew-scattering route to topological nonlinear Hall responses that bypasses conventional symmetry constraints.

2604.28090 2026-05-01 physics.optics nlin.PS

Bound states of solitons in fiber lasers

光纤激光器中孤子束缚态

Yudong Cui, Tianchang Lu, Yusheng Zhang, Dong Mao, Boris A. Malomed

AI总结 本文综述了光纤激光器中双孤子及多孤子耗散孤子束缚态的理论与实验研究,探讨了复杂吉金斯-兰道方程及其束缚态的理论基础,以及最新实验发现,包括多孤子束缚态及时频域束缚态的研究。

Comments to be published in Physics Reports

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AI中文摘要

本文系统回顾了光纤激光器中双孤子及多耗散孤子束缚态的理论和实验研究成果。文章详细阐述了支撑光纤中孤子分子形成和稳定化的理论基础,包括复杂吉金斯-兰道方程及其束缚态,随后详述了实验发现,包括非常近期的研究结果。特别包括了光纤中多孤子束缚态、时域和频域束缚态、单组分(标量)和双组分(向量)两组分和多组分孤子模式,以及基于多模光纤的时频域耗散孤子束缚态的研究结果。

英文摘要

This article presents a systematic review of theoretical and experimental findings for bound states of two and several dissipative solitons in fiber lasers. The theoretical basis underlying the formation and stabilization of soliton molecules in the fibers, which is provided by the complex Ginzburg-Landau equations and bound states of such equations, is presented in necessary detail, which is followed by a detailed presentation of experimental findings, including very recent ones. In particular, included are the results for the multi-soliton bound states in the fibers, as well as for the bound states in the temporal and frequency domains, single-component (scalar) and two-component (vector), two- and multi-soliton modes, as well as for bound states of spatiotemporal dissipative solitons in the lasers based on multimode fibers.

2604.28088 2026-05-01 cond-mat.mes-hall

Giant Spin Magnetization from Quantum Geometry in Altermagnets

量子几何诱导的巨量自旋磁化

Neelanjan Chakraborti, Sudeep Kumar Ghosh, Snehasish Nandy

AI总结 研究量子几何机制在中心对称系统中产生线性自旋磁化,揭示自旋旋转量子度量是唯一允许的响应机制,并通过实验材料展示其巨量自旋磁化特性。

Comments 10 pages, 3 figures

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AI中文摘要

自旋分裂带结构的Altermagnets在平衡自旋磁化为零的情况下,使得场诱导响应成为探测其量子几何的直接手段。在此背景下,一个核心问题在于,在中心对称系统中,哪种量子几何机制能够产生线性自旋磁化。本文发展了一个基于广义量子几何张量的统一框架,该张量结合了布洛赫态的动量平移和自旋旋转,将自旋磁化分解为平衡、电场驱动和磁场驱动的贡献。我们证明,反演对称性禁止中心对称系统中的线性电场响应,而$C_n T$对称性进一步抑制Altermagnets中的平衡贡献。因此,中心对称Altermagnets提供了一个特别清晰的实现,其中磁场诱导的自旋磁化作为唯一允许的线性量子几何响应出现。我们证明,这一贡献完全源自自旋旋转量子度量,确立其为此类系统中的唯一线性量子几何机制。利用代表性中心对称Altermagnets,包括$d$-波化合物$\mathrm{FeSb}_2$和$g$-波化合物$\mathrm{CrSb}$,我们表明自旋旋转量子度量直接控制这一响应。关键的是,我们预测在约$10\,\mathrm{mT}$的磁场下,自旋磁化可达$10^{-2}μ_B\,\mathrm{nm}^{-3}$的量级,超过传统磁体的典型实验值几个数量级。我们的结果识别了在中心对称系统中普遍作用的自旋磁化量子几何机制,并确立了中心对称Altermagnets作为其实验检测的理想平台,具有在自旋电子学中的潜在应用。

英文摘要

Altermagnets host spin-split band structures while exhibiting vanishing equilibrium spin magnetization, making field-induced responses a direct probe of their quantum geometry. A central question, in this regard, is which quantum-geometric mechanism can generate a linear spin magnetization in centrosymmetric systems. Here we develop a unified framework based on a generalized quantum geometric tensor that incorporates both momentum translations and spin rotations of Bloch states, and decompose spin magnetization into equilibrium, electric-field-driven, and magnetic-field-driven contributions. We show that inversion symmetry forbids the linear electric-field response in centrosymmetric systems, while $C_n T$ symmetry further suppresses the equilibrium contribution in altermagnets. Consequently, centrosymmetric altermagnets provide a particularly clean realization in which the magnetic-field-induced spin magnetization emerges as the only symmetry-allowed linear quantum-geometric response. We demonstrate that this contribution originates entirely from the spin-rotation quantum metric, establishing it as the sole linear quantum-geometric mechanism in such systems. Using representative centrosymmetric altermagnets, including the $d$-wave compound $\mathrm{FeSb}_2$ and the $g$-wave compound $\mathrm{CrSb}$, we show that the spin-rotation quantum metric directly controls this response. Crucially, we predict a giant linear spin magnetization of order $10^{-2}μ_B\,\mathrm{nm}^{-3}$ at magnetic fields of $\sim 10\,\mathrm{mT}$, exceeding typical experimental values for conventional magnets by several orders of magnitude. Our results identify a universal quantum geometric mechanism of spin magnetization operative in centrosymmetric systems in general, and establish centrosymmetric altermagnets as an ideal platform for its experimental detection with potential applications in spintronics.

2604.28086 2026-05-01 math.AP

Nonlinear evolution equations with a non-Lipschitz perturbation: convergence of successive approximations and uniqueness of solutions

非线性发展方程与非利普希茨扰动:连续逼近的收敛性与解的唯一性

G. Diaz, J. I. Dıaz

AI总结 本文研究非线性发展方程在Banach空间中由m-准单射算子A支配的解的存在性和唯一性,考虑不满足利普希茨条件的扰动项。

Comments 24 pages 1 figure

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AI中文摘要

本文研究由m-准单射算子A在Banach空间中支配的非线性发展方程的解的存在性和唯一性,考虑不满足利普希茨条件的扰动项。

英文摘要

This paper investigates the existence and uniqueness of solutions for a nonlinear evolution equation governed by an m-accretive operator A in a Banach space, presenting a perturbation term that does not satisfy the Lipschitz condition.

2604.28085 2026-05-01 math.AG math.CV

Failure of the semi log canonical Abundance for compact Kähler threefolds

半 log canonical 丰度在紧 Kähler 三维流形上的失效

Swapnajit Das

AI总结 本文展示紧 Kähler 变量在三维时半 log canonical 丰度失效,构造了反例表明 K_X 非负但 κ 为零,而 K_X 不是半 ample。同时证明若起始为紧 Kähler 半 dlt 对,则丰度成立。

Comments Comments are welcome

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AI中文摘要

本文展示紧 Kähler 变量在三维时半 log canonical 丰度失效。具体地,我们构造了一个紧 Kähler (不可约) slc 三维流形 (X, 0),使得 K_X 非负且 κ(˜X, K_˜X+˜D)=0,其中 μ:(˜X, ˜D)→X 是正则化映射,但 K_X 不是半 ample。另一方面,我们证明若起始为紧 Kähler 半 dlt 对,则丰度成立,即若 (X, Δ) 是三维紧 Kähler 半 dlt 对且 K_X+Δ 非负,则其是半 ample。此外,我们还证明若 (X, Δ) 是三维紧 Kähler slc 对,K_X+Δ 非负,且对于所有 i,κ(X'_i, Δ'_i+D'_i)>0,其中 μ:⊔(X'_i, Δ'_i+D'_i)→(X,Δ) 是正则化,则 K_X+Δ 是半 ample。

英文摘要

In this article we show that the semi log canonical abundance for compact Kähler varieties fails in dimension $3$. More specifically we construct a counterexample of a compact Kähler (irreducible) slc threefold $(X, 0)$ such that $K_X$ is nef and $κ(\tilde X, K_{\tilde X}+\tilde D)=0$, where $μ:(\tilde X, \tilde D)\to X$ is the normalization morphism, but $K_X$ is not semiample. On the other hand, we show that if we start with a compact Kähler semi-dlt pair, then the abundance does hold, i.e., if $(X, Δ)$ is a compact Kähler sdlt pair of dimension $3$ such that $K_X+Δ$ is nef, then it is semiample. We also show that if $(X, Δ)$ is a compact Kähler slc pair of dimension $3$, $K_X+Δ$ is nef, and $κ(X'_i, Δ'_i+D'_i)>0$ for all $i$, where $μ:\sqcup(X'_i, Δ'_i+D'_i)\to (X,Δ)$ is the normalization, then $K_X+Δ$ is semiample.

2604.28084 2026-05-01 eess.SY cs.SY

Intelligent Self-tuning Active EMI Filtering for Electrified Automotive Power Systems Using Reinforcement Learning

基于强化学习的智能自适应电磁干扰滤波器用于电动汽车电力系统

Mahuizi Lu, Kelin Jia, Rajib Goswami, Yukun Hu

AI总结 本文提出基于强化学习的智能自适应电磁干扰滤波器,通过马尔可夫决策过程动态调整滤波参数,提升电磁兼容性和系统效率,实验显示在宽频范围内实现25-30dB的干扰衰减。

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AI中文摘要

现代交通运输系统的电气化和智能化对汽车电力电子的电磁兼容性、可靠性和适应性提出了严格要求。在电动汽车和自动驾驶车辆中,高频开关电源转换器产生的电磁干扰可能影响安全关键功能、车载通信和系统效率。传统被动电磁干扰滤波器虽然稳健,但往往过大且缺乏适应性,导致重量、体积和能量损失增加。本文提出基于强化学习的智能自适应电磁干扰滤波方法,将电磁干扰抑制问题建模为马尔可夫决策过程,使强化学习代理能够持续适应时间变化的干扰特性。为提高在复杂非平稳条件下的鲁棒性和泛化能力,采用变分自编码器进行紧凑的状态表示,同时采用基于噪声的探索机制提高学习效率并防止次优收敛。所提方法通过实验测量的汽车电动驱动单元电磁干扰频谱在MATLAB/Simulink联合仿真框架中进行评估。结果表明,与传统控制策略和被动滤波方案相比,在宽频范围内实现了25-30dB的干扰衰减改进。通过减少对过大被动元件的依赖,使该框架支持轻量、节能和可靠的电力电子系统,适用于智能和绿色交通应用。

英文摘要

The rapid electrification and intelligence of modern transportation systems place stringent demands on the electromagnetic compatibility, reliability, and adaptability of automotive power electronics. In electric and autonomous vehicles, electromagnetic interference (EMI) generated by high-frequency switching power converters can compromise safety-critical functions, in-vehicle communications, and system efficiency under dynamic operating conditions. Conventional passive EMI filters, while robust, are often oversized and lack adaptability, leading to increased weight, volume, and energy losses. This paper proposes an intelligent self-tuning active EMI filtering approach for electrified automotive power systems based on reinforcement learning (RL). The EMI mitigation problem is formulated as a Markov decision process, enabling an RL agent to continuously adapt filter parameters in response to time-varying interference characteristics. To improve robustness and generalisation under complex and non-stationary conditions, a variational autoencoder is employed for compact state representation, while a noise-based exploration mechanism enhances learning efficiency and prevents suboptimal convergence. The proposed method is evaluated using experimentally measured EMI spectra from an automotive electric drive unit within a MATLAB/Simulink co-simulation framework. Results demonstrate consistent EMI attenuation improvements of 25-30 dB across a wide frequency range compared with conventional control strategies and passive filtering solutions. By reducing reliance on oversized passive components and enabling adaptive EMI suppression, the proposed framework supports lightweight, energy-efficient, and reliable power-electronic systems for intelligent and green transportation applications.

2604.28083 2026-05-01 physics.optics

Analysis of Electromagnetic Scattering from Semiconductor Nanostructures by Solving Coupled Volume Integral and Two-fluid Hydrodynamic Equations

半导体纳米结构电磁散射分析:求解耦合体积积分与双流体流体动力学方程

Doolos Aibek Uulu, Meruyert Khamitova, Rui Chen, Liang Chen, Ping Li, Hakan Bagci

AI总结 本文提出基于体积积分方程的求解器,用于分析半导体纳米结构的电磁散射,通过耦合体积积分方程与双流体流体动力学方程,准确捕捉空间色散效应和低频声子模,展示其在描述声子共振和局域表面等离子体共振蓝移方面的独特优势。

详情
AI中文摘要

基于半导体等离子体纳米结构的局部表面等离子体模式在近红外区域支持。与金属纳米结构不同,它们支持自由电子和空穴,需要双流体流体动力学Drude方程(HDE)来准确捕捉空间色散效应和低频声子模,这些无法由单流体模型描述。本文提出了一种基于体积积分方程(VIE)的求解器,用于分析半导体纳米结构的电磁散射。所提出的方法将VIE(以电通量密度和自由电子和空穴极化电流为变量)与双流体HDE耦合。耦合系统使用四面体网格离散化,并使用双层迭代求解器高效求解。与基于有限元的方法不同,所提出的VIE方法不需要全域网格划分,并且本质上满足辐射条件,从而消除了人工吸收边界。InSb型半导体纳米结构的数值结果展示了所提出的VIE求解器的精度和效率,以及其捕捉独特光学现象的能力,如声子共振和局域表面等离子体共振的蓝移,这些无法由单流体HDE或经典Drude模型描述。

英文摘要

Semiconductor-based plasmonic nanostructures support localized surface plasmon modes in the infrared region. Unlike metallic nanostructures, they support both free electrons and holes, requiring a two-fluid hydrodynamic Drude equation (HDE) to accurately capture spatial dispersion effects and low-frequency acoustic plasmon modes that cannot be described by single-fluid models. In this work, a volume integral equation (VIE)-based solver is proposed for the analysis of electromagnetic scattering from semiconductor nanostructures. The proposed approach couples the VIE, formulated in terms of the electric flux density and the free-electron and hole polarization currents, with the two-fluid HDE. The coupled system is discretized using a tetrahedral mesh and solved efficiently using a two-level iterative solver. In contrast to finite-element-based methods, the proposed VIE-based approach does not require domain-wide meshing and inherently satisfies the radiation condition, thereby eliminating artificial absorbing boundaries. Numerical results for InSb-type semiconductor nanostructures demonstrate the accuracy and efficiency of the proposed VIE-based solver and its ability to capture unique optical phenomena, such as acoustic plasmon resonances and the blueshift of localized surface plasmon resonances, that cannot be described by the single-fluid HDE or classical Drude-based models.