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2605.30192 2026-05-29 astro-ph.HE astro-ph.CO

The Northern Cross Fast Radio Burst project: VI. The INCART public database

北十字快速射电暴项目:VI. INCART公共数据库

L. Bruno, G. Bernardi, M. Pilia, D. Pelliciari, A. Geminardi, F. Fiori, V. Galluzzi, G. Naldi, M. Trudu, A. Zanichelli

AI总结 本文介绍了意大利北十字射电暂现源星表(INCART)公共平台,用于发布北十字射电干涉仪观测到的快速射电暴数据产品,包括频率-时间序列数据集和最佳拟合物理参数目录,以促进科学再分析和协同研究。

Comments 8 pages, 6 figures. Accepted for publication in PASA. INCART is available here: https://ngc-frb-incart.ira.inaf.it/

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AI中文摘要

快速射电暴(FRB)是河外起源的明亮(央斯基量级)、短时标(约1毫秒)的闪光。单次事件的观测现已通过大天区巡天得到补充,提供了FRB星表并实现了首次群体研究。北十字(NC)射电干涉仪是执行FRB观测的仪器之一。在本文中,我们介绍了意大利北十字射电暂现源星表({\tt INCART}),这是一个用于分发NC数据产品的公共平台。{\tt INCART}通过可管理的频率-时间序列数据集和包含最佳拟合物理参数的星表,向学界提供NC观测到的FRB。{\tt INCART}的设计保证了FRB特性科学再分析的可能性,并考虑到处理流程的未来版本。此外,{\tt INCART}专注于长期存储优化,这是最先进仪器的关键方面。NC的FRB数据公开访问最大化了该数据集的遗产价值,促进了与其他公开星表的协同作用,并推动了研究小组的合作。

英文摘要

Fast radio bursts (FRBs) are bright (Jansky-level) and short-duration ($\sim 1$ ms) flashes of extragalactic origin. Observations of single events have now been complemented by large-area surveys, delivering FRB catalogues and enabling the first population studies. The Northern Cross (NC) radio interferometer is one of the instruments performing observations of FRBs. In this work, we present the Italian Northern Cross Atlas of Radio Transients ({\tt INCART}), a public platform for the distribution of data products from the NC. {\tt INCART} makes available to the community the FRBs observed by the NC through manageable frequency-time series datasets and catalogues with best-fit physical parameters. The design of {\tt INCART} guarantees the possibility of scientific re-analysis of the FRB properties, in view also of future releases of the processing pipeline. Furthermore, {\tt INCART} focuses on long-term storage optimisation, which is a key aspect of state-of-the-art instrumentation. Public access to the FRB data from the NC maximises the legacy value of the collection, facilitates the synergy with other publicly-available catalogues, and fosters research group collaborations.

2605.30191 2026-05-29 math.FA

On $L^p$-spaces of functions with values in locally convex spaces

关于取值于局部凸空间的函数的$L^p$空间

Matthieu F. Pinaud, Humberto Prado

AI总结 研究取值于局部凸空间的Lusin可测函数,探讨非可度量化情形下的点态极限病理现象,并建立基于该可测性概念的$L^p$空间的逼近与稠密性结果。

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AI中文摘要

我们研究取值于局部凸空间的Lusin可测函数。特别地,我们考察Lusin可测函数序列的点态极限行为,并展示在非可度量化设定中出现的病态现象。此外,我们建立了基于这种可测性概念构造的$L^p$空间的逼近和稠密性结果,包括Hausdorff局部凸空间中简单函数的稠密性以及通过二进逼近得到的收敛结果。

英文摘要

We study Lusin-measurable functions with values in locally convex spaces. In particular, the behavior of pointwise limits of sequences of Lusin-measurable functions and exhibit pathological phenomena arising in the nonmetrizable setting. Moreover, we establish approximation and density results for $L^p$-spaces constructed with this notion of measurability, including the density of simple functions in Hausdorff locally convex spaces and convergence results obtained through dyadic approximations.

2605.30186 2026-05-29 math.FA math.LO math.SP

Spectral embedding through weak* limit of finite-dimensional approximations

通过有限维逼近的弱*极限的谱嵌入

Fabrice Nonez

AI总结 本文通过经典分析论证,无需非标准技术或超积,重新证明了谱嵌入定理:任何稠定对称算子可通过将Hilbert空间嵌入到L2空间中的乘法算子来延拓。

Comments 37 pages

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AI中文摘要

本文旨在研究一个过程,该过程给出了谱嵌入定理的另一种证明:任何稠定对称算子可以通过将Hilbert空间嵌入到L2空间中的乘法算子来延拓。此外,该过程旨在用于特定算子,其中可能找到自然的谱嵌入或等价关系。该过程先前已在arXiv:2411.06281和arXiv:2511.18189中通过非标准技术引入。我们的贡献在于通过经典分析论证重新表述该理论,而不使用非标准技术或超积。

英文摘要

The scope of this text is to study a process that induces another proof of the Spectral Embedding Theorem: that any densely defined symmetric operator can be extended by a multiplication operator through an embedding of the Hilbert space into an $L_2$ space. Furthermore, that process is meant to be used for specific operators, where natural spectral embeddings or equivalences may be found. That process has previously been considered in arXiv:2411.06281 and in arXiv:2511.18189, where it has been introduced through nonstandard techniques. Our contribution aims to be the reformulation of the theory through classical analysis arguments, without the use of nonstandard techniques nor ultraproducts.

2605.30183 2026-05-29 eess.SY cs.SY

Fault-Ride-Through Coordination Strategy for Offshore AC Islands with Multi-Infeed HVDC Interconnections

多馈入HVDC互联的海上交流孤岛故障穿越协调策略

Eleni Tsotsopoulou, Vasileios Psaras, Dionysios Moutevelis, Oriol Gomis-Bellmunt, Alexandros Paspatis

AI总结 针对多馈入HVDC互联的海上交流孤岛,提出一种协调控制策略,通过引入零有功/无功注入和故障后有功下垂控制,实现故障穿越并满足电网规范。

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AI中文摘要

大规模海上风电场被认为是实现可持续电力系统的关键资产。这些系统通常配置为海上交流孤岛,其集成很大程度上依赖于高压直流(HVDC)技术。这种拓扑虽然能够实现长距离海上输电的经济性,但可能带来运行挑战。具体而言,海上交流孤岛在故障期间的运行以及电网规范要求的满足被识别为其大规模部署的主要挑战。为解决这一紧迫问题,本文提出了一种针对多馈入海上交流孤岛中不同参与换流器在故障穿越(FRT)运行期间的全面协调控制策略。所提策略在HVDC和风电场换流器的FRT方案中引入了高级控制功能,例如故障期间的有功和无功零注入,以及故障后有功下垂控制协调以解决功率不平衡。通过PSCAD/EMTDC中的广泛仿真以及功率硬件在环(PHIL)实验结果,验证了所提FRT协调策略的有效性,同时考虑了交流和直流故障。

英文摘要

Large-scale offshore Wind Farms (WFs) are considered key assets towards realizing a sustainable power system. These systems are often configured as offshore AC islands and their integration largely depends on the High-Voltage-Direct-Current (HVDC) technology. This topology, while it enables cost-effective transmission over large offshore distances, may lead to operational challenges. Specifically, the operation of offshore AC islands during faults and the grid code requirement fulfillment are identified as a major challenges for their large-scale deployment. To address this pressing issue, a comprehensive coordination control strategy for the different participating converters in multi-infeed AC offshore islands during Fault Ride Through (FRT) operation is presented in this work. The proposed strategy introduces advanced control functions in the FRT schemes of both the HVDC and WF converters, such as zero active and reactive power injection during faults, as well as post-fault active power droop control coordination to tackle power imbalances. The proposed FRT coordination strategy is validated through both extensive simulations in PSCAD/EMTDC, as well as with Power Hardware-in-the-Loop (PHIL) experimental results, considering both AC and DC faults.

2605.30181 2026-05-29 math.NA cs.NA math.OC

Generalized matrix nearness problems II

广义矩阵逼近问题 II

Rongbiao Thomas Wang, Chi-Kwong Li, Lek-Heng Lim

AI总结 研究广义矩阵逼近问题,通过引入仿射项、克罗内克积和任意正交不变范数进行扩展,提出适用于任意Schatten范数的迭代算法并证明全局收敛。

Comments 23 pages, 4 figures

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AI中文摘要

给定矩阵$A$,矩阵逼近问题寻求一个$X$,在$X$的各种约束下最小化$\lVert A - X\rVert$,从而最接近$A$。广义矩阵逼近问题则使用三个给定矩阵$A,B,C$和$\lVert A - BXC\rVert$代替$\lVert A - X\rVert$。我们从三个方面扩展了先前对该问题的研究:引入仿射项,以多种方式用克罗内克积替换矩阵乘积,并将Frobenius范数推广到任意正交不变范数。我们将以闭式解解决其中几个问题。对于其余问题,我们开发了一种适用于任何Schatten范数的迭代算法,并证明无论初始点如何,该算法都收敛到全局最小值。此外,该算法纯粹依赖于数值线性代数,并且特别地不计算任何显式梯度或次梯度。在此过程中,我们还将证明对于秩约束的广义矩阵逼近问题,不存在Mirsky型定理。

英文摘要

Given a matrix $A$, a matrix nearness problem seeks an $X$ that most closely approximates $A$ in the sense of minimizing $\lVert A - X\rVert$ under a variety of constraints on $X$. A generalized matrix nearness problem seeks the same but with three given matrices $A,B,C$ and $\lVert A - BXC\rVert$ in place of $\lVert A - X\rVert$. We extend previous studies of the latter problem in three directions: incorporating an affine term, replacing matrix product by Kronecker product in various manners, and generalizing Frobenius norm to any orthogonally invariant norm. We will solve several of these in closed form. For the rest, we develop an iterative algorithm that works for any Schatten norm, proving that it converges to a global minimizer regardless of the initial point. In addition, the algorithm relies purely on numerical linear algebra, and notably does not compute any explicit gradients or subgradients. Along the way, we will also show that there is no Mirsky-type theorem for rank constrained generalized matrix nearness problems.

2605.30180 2026-05-29 nucl-th

The polarization of thermal dileptons emitted in high-energy heavy-ion collisions

高能重离子碰撞中热双轻子的极化

Han Gao, Xiang-Yu Wu, Charles Gale, Greg Jackson, Sangyong Jeon

AI总结 通过结合次领头阶虚光子谱函数和流体力学模拟,计算热双轻子发射与极化可观测量,揭示极化对夸克胶子等离子体介质性质的敏感性。

Comments 17 pages, 14 figures

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AI中文摘要

本文展示了热双轻子发射和极化观测量的计算。它包含一个综合框架,该框架由强耦合下完整到次领头阶的虚光子谱函数和iEBE-MUSIC流体力学模拟组成。热轻子对的极化被证明对夸克-胶子等离子体的介质性质敏感。我们考虑在LHC特定条件下进行的Pb+Pb碰撞,检查在不同参考系中测量的极化的大小和行为、预平衡胶子丰度的影响,并推导出双电子和双缪子极化之间的一一对应关系。

英文摘要

This work presents calculations of thermal dilepton emission and polarization observables. It features a comprehensive framework which comprises virtual photon spectral functions complete at next-to-leading-order in the strong coupling and iEBE-MUSIC hydrodynamic simulations. The polarization of thermal lepton pairs is shown to be sensitive to in-medium properties of the quark-gluon plasma. We consider Pb+Pb collisions performed in conditions specific to the LHC and examine the magnitude and behaviour of the polarization as measured in different frames, the effects of the pre-equilibrium gluon abundance, and we derive a one-to-one mapping between dielectron and dimuon polarization.

2605.30178 2026-05-29 stat.ME stat.CO

Cellwise Robust Discriminant Analysis

单元稳健判别分析

Fabio Centofanti, Can Hakan Dagidir, Mia Hubert, Peter J. Rousseeuw

AI总结 针对数据矩阵中的单元异常值,提出基于单元稳健估计和惩罚最大似然的判别分析方法(cellQDA/cellLDA),在训练和预测中同时处理单元和个案异常值及缺失值。

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AI中文摘要

经典判别分析(DA)基于每个类别的均值和经验协方差矩阵,两者都对数据中的异常值敏感。过去关注的是个案异常值,即远离的数据点。但如今对单元异常值(即数据矩阵中的意外条目)的兴趣日益增加。因为一个或几个异常单元而删除整个个案会丢失大量信息。单元稳健方法旨在检测异常单元并保留其他单元的信息。我们提出一种DA方法,通过单元和个案稳健估计量估计每个类别的位置和协方差来进行训练,该方法也能处理缺失值。我们方法的主要创新在于对测试数据的预测,测试数据本身可能包含异常单元和缺失值。新的稳健判别函数通过惩罚最大似然从新的统计模型推导得出。我们专注于二次DA,但也涵盖线性DA的设置。新的cellQDA和cellLDA方法在模拟中表现良好。该方法在真实数据上进行了说明,并通过图形展示解释结果。

英文摘要

Classical discriminant analysis (DA) is based on the mean and empirical covariance matrix of each class, both of which are sensitive to outliers in the data. In the past the focus was on casewise outliers, that is, datapoints that lie far away. But nowadays there is increasing interest in cellwise outliers, that are unexpected entries in the data matrix. Removing an entire case because it has one or a few outlying cells would lose much information. Cellwise robust methods aim to detect the outlying cells and to preserve the information in the other cells. We propose a DA method that is trained by estimating the location and covariance of each class by cellwise and casewise robust estimators, that can also handle NA's. The main novelty of our approach is in the prediction on test data, that may contain outlying cells and NA's themselves. The new robust discriminant function is derived from a novel statistical model by penalized maximum likelihood. We focus on quadratic DA, but also cover the setting of linear DA. The new cellQDA and cellLDA methods perform well in simulation. The approach is illustrated on real data, and the results are interpreted with the help of graphical displays.

2605.30177 2026-05-29 astro-ph.EP

The Architecture of the 14 Herculis System Suggests Primordial Ejection of a Massive Planet

14 Herculis 系统的结构暗示了一颗大质量行星的原始抛射

Tiger Lu, Sarah C. Millholland, Malena Rice, Brennen Black, Daniella C. Bardalez Gagliuffi, William O. Balmer, Laurent Pueyo, Mark R. Giovinazzi, Timothy D. Brandt

AI总结 通过 N 体模拟行星-行星散射,再现了 14 Herculis 系统两颗偏心、显著错位的超级木星的轨道结构,并表明需要一颗额外大质量行星的抛射来解释其动力学历史。

Comments 13 pages, 6 figures. In review at ApJ. Comments welcome!

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AI中文摘要

14 Herculis 系统拥有两颗在偏心且显著错位轨道上的超级木星。这种轨道结构构成了一个需要解释的动力学难题。在这项工作中,我们使用大规模的行星-行星散射 N 体模拟套件重现了该系统的动力学历史和当前结构。我们的结果表明,行星-行星散射能够再现 14 Her 独特的轨道结构,但前提是系统中最初存在额外的、随后被抛射的大质量天体。任何此类被抛射行星的质量反过来可以约束系统的初始配置。我们还分析了系统当前的长期演化,并得出结论:尽管目前很可能存在非平凡的偏心率和倾角振荡,但这些振荡的幅度不足以使潮汐力有意义地改变系统的结构。最后,我们讨论了未来 Gaia 数据发布和 Roman 任务的观测如何将 14 Her 的动力学历史置于更广泛的、种群层面的框架中。

英文摘要

The 14 Herculis system hosts two super-Jupiters on eccentric, significantly misaligned orbits. This orbital architecture represents a dynamical puzzle that demands explanation. In this work, we reproduce the system's dynamical history and current architecture using a large suite of N-body simulations of planet-planet scattering. Our results demonstrate that planet-planet scattering is able to reproduce 14 Her's peculiar orbital architecture, but only if additional massive bodies were initially present in the system that were subsequently ejected. The mass of any such ejected planet can in turn constrain the system's initial configuration. We also analyze the present-day secular evolution of the system and conclude that while there are most likely nontrivial eccentricity and inclination oscillations currently occurring, the magnitudes of these oscillations are not strong enough to allow tidal forces to meaningfully alter the system's architecture. Finally, we discuss how forthcoming observations from future Gaia data releases and the Roman mission may situate 14 Her's dynamical history within a broader, population-level framework.

2605.30176 2026-05-29 math-ph gr-qc math.MP

The Fermionic Signature Operator in the Reissner-Nordström Geometry in Horizon-Penetrating Coordinates

Reissner-Nordström 几何中穿透视界坐标下的费米子签名算子

Felix Finster, Christoph Krpoun

AI总结 研究在穿透视界坐标下Reissner-Nordström几何中Dirac方程至柯西视界,通过质量分解定理给出时空内积的协变表示,计算费米子签名算子和费米子通量算子的谱并证明它们是有界对称算子,构造费米子投影态并证明其满足Hadamard条件,最后给出费米子通量算子的物理解释。

Comments 25 pages, LaTeX, one figure

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AI中文摘要

我们研究了在穿透视界坐标下Reissner-Nordström几何中直至柯西视界的Dirac方程。证明了一个质量分解定理,该定理给出了时空内积的协变表示,自然涉及费米子签名算子和费米子通量算子。我们计算了它们的谱,并证明两者都是大质量Dirac方程解空间$\mathcal{H}_m$上的有界对称算子。构造了相应的费米子投影态,并证明其满足Hadamard条件。最后,我们给出了费米子通量算子的一些物理解释。

英文摘要

We study the Dirac equation in the Reissner-Nordström geometry in horizon-penetrating coordinates up to the Cauchy horizon. A mass decomposition theorem is proved, which gives a covariant representation of the spacetime inner product that naturally involves the fermionic signature operator and the fermionic flux operator. We compute their spectra and show that both are bounded symmetric operators on the solution space $\mathcal{H}_m$ of the massive Dirac equation. The corresponding fermionic projector state is constructed and shown to satisfy the Hadamard condition. Lastly, we give some physical interpretations of the fermionic flux operator.

2605.30173 2026-05-29 cond-mat.mes-hall

Coherent and Dissipative Spin Torques in Quantum Dots: A Unified Framework for Quantum Spin Dynamics

量子点中的相干与耗散自旋扭矩:量子自旋动力学的统一框架

Dominic Ruckert, Stepan Kovarik, Richard Schlitz, Mirco Grellmann, Aishwarya Vishwakarma, Pietro Gambardella, Sebastian Stepanow

AI总结 本文提出一个统一理论框架,通过Lindblad主方程描述分子量子点中自旋转移、自旋扭矩和自旋共振,涵盖相干交换相互作用和耗散自旋扭矩效应,并扩展到耦合自旋系统,揭示自旋相干性和纠缠对局域自旋扭矩的响应。

Comments for data availability, see https://doi.org/10.3929/ethz-c-000798476

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Journal ref
Phys. Rev. Research 8, 023121- Published 5 May, 2026
AI中文摘要

通过自旋极化隧穿对单自旋的操控为原子尺度的量子控制开辟了新途径。我们提出了一个理论框架,描述弱耦合到磁性电极的分子量子点中的自旋转移、自旋扭矩和自旋共振。通过从微观隧穿过程推导Lindblad主方程,我们在统一方法中捕获了相干交换相互作用和耗散自旋扭矩效应。我们分析了通过局域轨道的电荷输运如何影响自旋动力学,并表明随时间调制隧穿率可以诱导电子自旋共振。该框架进一步扩展到耦合自旋系统,揭示了自旋相干性和纠缠如何响应局域自旋扭矩,并强调了输运驱动的退相干源。我们的结果提供了一个通用模型来解释自旋分辨隧穿实验,并将经典自旋扭矩概念扩展到量子领域。

英文摘要

The manipulation of single spins through spin-polarized tunneling opens new routes for quantum control at the atomic scale. We present a theoretical framework describing spin-transfer, spin torques and spin resonance in molecular quantum dots weakly coupled to magnetic electrodes. By deriving a Lindblad master equation from microscopic tunneling processes, we capture both coherent exchange interactions and dissipative spin torque effects within a unified approach. We analyze how charge transport through localized orbitals influences spin dynamics and show that modulating the tunneling rates in time can induce electron spin resonance. This framework is further extended to coupled spin systems, revealing how spin coherence and entanglement respond to local spin torques and highlighting sources of transport-driven decoherence. Our results provide a general model to interpret spin-resolved tunneling experiments and extend classical spin torque concepts into the quantum regime.

2605.30172 2026-05-29 cs.CE eess.SP physics.med-ph

A Lumped-Element Electrical Model of the Human Head for Brain-Oriented Applications

面向脑部应用的集总参数人脑电学模型

Angelo Faccia, Ermanno Citraro, Francesco P. Andriulli

AI总结 提出一种基于三壳几何结构的集总参数电路模型,通过径向和切向RC支路模拟脑组织频散特性,验证了模型与半解析球谐参考解的一致性。

Comments 4 pages, 4 figures. To appear in the proceedings of the APS March Meeting 2026, Detroit, Michigan

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AI中文摘要

在这项工作中,我们提出了一种用于电准静态头部建模的紧凑替代电路。考虑了三层几何结构(脑、颅骨、头皮),每层通过径向和切向路径建模,并实现为RC支路。频率相关的组织电导率和介电常数被映射为色散电阻和电容元件。该模型在多种几何配置和工作频率下与半解析球谐参考解进行了验证,显示出良好的一致性。忽略色散和电容路径会导致在所考虑频率范围内头皮电位的过高估计,凸显了色散RC电路建模的必要性。

英文摘要

In this work, we present a compact surrogate circuit for electro-quasi-static (EQS) head modeling. A three-shell geometry (brain, skull, scalp) is considered, and each layer is modeled through radial and tangential pathways, implemented as RC branches. Frequency-dependent tissue conductivity and permittivity are mapped into dispersive resistive and capacitive elements. The model is validated against a semi-analytical spherical-harmonics reference solution over multiple geometrical configurations and operating frequencies, demonstrating good agreement. Neglecting dispersion and capacitive pathways can lead to an overestimation of scalp potentials over the considered frequency range, highlighting the need for dispersive RC circuit modeling.

2605.30165 2026-05-29 quant-ph physics.chem-ph physics.comp-ph

Tunneling phase diagram: A machine-learning framework for multidimensional kinetic isotope effects

隧穿相图:多维动力学同位素效应的机器学习框架

Xinrui Yang, Zhigang Wang

AI总结 提出隧穿相图机器学习框架,通过解码KIE与隧穿因子κ的非线性关系,实现真实隧穿强度的解耦,并发现300-600K区间的高KIE-低κ异常现象。

Comments 17 pages, 7 figures

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AI中文摘要

动力学同位素效应(KIE)是量子隧穿的传统探针,但其复合性质将隧穿与零点能和经典动力学混为一谈。这里,我们引入隧穿相图,这是一个机器学习框架,通过解码KIE与隧穿因子(κ)之间的非线性关系来解耦真实隧穿强度。该框架具有卓越的保真度(R² > 0.98,RMSE = 0.21),揭示了在300-600 K范围内存在异常的高KIE-低κ区域,从而为量子隧穿的定量评估定义了一个范式。

英文摘要

The kinetic isotope effect (KIE) is the conventional probe for quantum tunneling, yet its composite nature conflates tunneling with zero-point energy and classical kinetics. Here, we introduce the tunneling phase diagram, a machine-learning framework that decouples true tunneling strength by decoding the nonlinear relationship between KIE and the tunneling factor (\k{appa}). With exceptional fidelity (R^2 > 0.98, RMSE = 0.21), this framework reveals an anomalous high KIE-low \k{appa} spanning 300-600 K, thereby defining a paradigm for the quantitative assessment of quantum tunneling.

2605.30163 2026-05-29 math.GR

A finitely presented group of non-uniform exponential growth

一个有限呈现的非均匀指数增长群

Roman Sauer, Eduard Schesler

AI总结 通过Thompson群V,首次构造了有限呈现群和单群中具有非均匀指数增长的例子。

Comments 17 pages

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AI中文摘要

我们提供了第一个有限呈现的,以及第一个简单的,具有非均匀指数增长的群的例子。该例子由Thompson群V给出。

英文摘要

We provide the first example of a finitely presented, and the first example of a simple, group of non-uniform exponential growth. The example is given by Thompson's group V.

2605.30158 2026-05-29 stat.ME

High-Dimensional Data with Measurement Error

高维数据中的测量误差

Herman Tesso, Georges Nguefack-Tsague

AI总结 针对高维回归中协变量存在测量误差的问题,综述并比较了岭回归、Lasso、Dantzig选择器和弹性网及其误差校正变体的性能,通过模拟和真实数据提供实践建议。

Comments 21 pages, 0 figure

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AI中文摘要

在许多重要的统计分析中,协变量的数量 $p$ 通常超过数据规模 $n$,这种情形通常被称为高维。尽管在假设协变量无误差的高维回归方面取得了显著进展,但现实世界的数据经常涉及噪声或损坏的测量。如果不加以处理,测量误差可能会悄无声息地扭曲分析并误导结论。本文回顾并评估了一些适用于存在测量误差协变量的高维回归的统计推断方法。我们讨论了四种惩罚回归方法——岭回归、lasso、Dantzig选择器和弹性网——及其测量误差校正变体,并在线性加性且不相关的测量误差模型下进行了比较研究。通过模拟研究和对高维医学遗传数据的实际应用,我们展示了所研究的方法,表明校正程序的选择是问题特定的,并提供了实用建议以帮助实践者应对这一方法论领域。

英文摘要

In many important statistical analyses, the number of covariates $p$ often exceeds the data size $n$, a regime commonly referred to as high-dimensional. While considerable progress has been made in high-dimensional regression under the assumption of error-free covariates, real-world data frequently involve noisy or corrupted measurements. When left unaddressed, measurement errors can silently distort the analysis and mislead the conclusions. This paper reviews and evaluates some advisable statistical inference methods for high-dimensional regression in the presence of mismeasured covariates. We discuss four penalized regression methods -- ridge, lasso, Dantzig selector, and Elastic-net -- alongside their measurement-error-corrected variants, and conduct a comparative study under linear additive and uncorrelated measurement error models. Through simulation studies and a real application to high-dimensional medical genetic data, we illustrate the methods studied, show that the choice of correction procedure is problem-specific, and provide practical recommendations to help practitioners navigate this methodological landscape.

2605.30157 2026-05-29 stat.AP

Leveraging Large Language Models to Improve Precision in Randomized Controlled Trials

利用大型语言模型提高随机对照试验的精度

Jaylin Lowe, Adam Sales, Johann A. Gagnon-Bartsch

AI总结 本文探索如何安全、严谨地利用大型语言模型(LLM)的预测来提升随机对照试验(RCT)的精度,并通过三个案例验证其有效性。

Comments Submitted to Machine Learning and Artificial Intelligence for Causal Inference in the Behavioral and Social Sciences: Methodological Advances and Applications, a topical issue of the Zeitschrift für Psychologie

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AI中文摘要

大型语言模型(LLM)在统计研究和应用中越来越广泛,但也以信息不可靠或有偏见而闻名。在此,我们探讨是否能够以安全且严谨的方式利用LLM提高随机对照试验(RCT)的精度。借鉴利用观察性数据的类似工作,我们将LLM预测纳入RCT分析。虽然利用外部预测提高精度并非新概念,但以这种方式使用LLM预测的价值仍是一个开放性问题。我们开发了一个在此背景下最佳利用LLM预测的流程,并将其应用于三个不同的案例研究。我们发现,这些预测可以安全地提高精度,特别是在RCT缺乏预测性协变量或包含文本数据等适合LLM的协变量时。

英文摘要

Large language models (LLMs) are increasingly used in statistical research and applications. However,they are also notorious for unreliable or biased information. Here, we explore whether LLMs can be used to improve the precision of randomized controlled trials (RCTs) in a safe and rigorous way. Following similar work on leveraging observational data, we incorporate LLM predictions into an RCT analysis. While incorporating external predictions to improve precision is not new, the value of using LLM predictions in this manner is an open question. We develop a pipeline for best leveraging LLM predictions in this context and apply it to three different case studies. We find that these predictions can safely improve precision, particularly when the RCT lacks predictive covariates or contains covariates, such as text data, that are well-suited to LLMs.

2605.30156 2026-05-29 cs.DB

The Missing Dimensions in Geo-Distributed Database Evaluation

地理分布式数据库评估中缺失的维度

Oto Mraz, Kyriakos Psarakis, George Christodoulou, Paris Carbone, Asterios Katsifodimos

AI总结 针对现有地理分布式OLTP数据库评估忽略网络不稳定、数据位置和跨区域成本等问题,提出综合评估框架Gaia,揭示系统对网络敏感、网络成本主导部署费用及多区域容错机制开销被忽视等发现。

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AI中文摘要

地理分布式OLTP数据库广泛部署在云区域之间,但当前的评估实践并未涵盖这方面的挑战。现有基准测试假设网络条件稳定;它们缺乏数据和客户端位置的显式设置,并且很大程度上忽略了跨区域的数据传输成本。此外,大多数评估依赖于有限的地理分布模式。在本文中,我们提出了Gaia,一个全面的评估框架,以解决这些差距。我们使用Gaia对现有的地理分布式OLTP系统进行全面评估。我们将它们部署在多个云区域,使用不同的地理分布模式和可变的跨区域网络条件。在其他有趣的发现中,我们的框架揭示了:i) 大多数系统对网络不稳定性敏感,ii) 网络成本主导云部署费用,iii) 多区域容错机制引入了可测量的关键路径开销,这在先前的评估中常常被忽视。我们认为,在设计未来的地理分布式数据库时,必须重新思考性能、容错性和成本之间的权衡。

英文摘要

Geo-distributed OLTP databases are widely deployed across cloud regions, yet current evaluation practices do not cover the challenges of this aspect. Existing benchmarks assume stable network conditions; they lack explicit settings for data and client locality, and they largely ignore data transfer costs across regions. In addition, most evaluations rely on a limited set of geo-distribution patterns. In this paper, we propose Gaia, a comprehensive evaluation framework that addresses these gaps. We use Gaia to perform a comprehensive evaluation of existing geo-distributed OLTP systems. We deploy them across multiple cloud regions, using different geo-distribution patterns and variable cross-region network conditions. Among other interesting findings, our framework reveals that: i) most systems are sensitive to network instabilities, ii) network costs dominate cloud deployment expenses iii) multi-region fault-tolerance mechanisms incur measurable critical-path overhead that is often overlooked in prior evaluations. We argue that for the design of future geo-distributed databases, we must rethink the trade-offs between performance, fault-tolerance, and cost.

2605.30149 2026-05-29 cs.NE physics.optics

Deep Binarized Photonic Reservoir Computing for Ultrafast Multimedia Signal Processing

深度二值化光子储层计算用于超快多媒体信号处理

Muhammad Waqar Iqbal, Mohamad Alassir, Nicolas Marsal, Damien Rontani

AI总结 提出一种基于数字微镜器件超快二进制光学调制、随机介质光学散射、CMOS传感器高速光电探测和时分复用深层结构的深度光子神经网络,在储层计算框架下实现Gb/s级处理速率,并在视频、图像和语音识别等多媒体任务中达到最优性能。

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AI中文摘要

我们提出了一种基于数字微镜器件(DMD)超快二进制光学调制、随机介质光学散射、CMOS传感器高速光电探测以及时分复用深层结构的深度光子神经网络架构。该系统以吉比特每秒(Gb/s)的处理速率运行,基于储层计算(RC)框架,在包括视频、图像和语音识别在内的各种多媒体任务中实现了最先进的性能。我们表明,通过仔细优化关键的物理层内和层间超参数,可以显著增强深度光子RC系统通过平衡各层的记忆保留和动态响应来提取相关时空特征的能力。这种方法为用于高吞吐量实时多媒体信号处理的高度可扩展分层光子储层计算系统铺平了道路。

英文摘要

We present a deep photonic neural network architecture based on ultrafast binary optical modulation from a digital micro-mirror device (DMD), optical scattering in random medium, high-speed photodetection with a CMOS sensor, and time-multiplexed deep layer structure. Operating at Gigabit-per-second (Gb/s) processing rates, our system based on the reservoir computing (RC) framework achieves state-of-the-art performance across various multimedia tasks, including video, image and speech recognition. We show that the careful optimization of key physical intra- and inter-layer hyper-parameters can significantly enhance the deep photonic RC system ability to extract relevant temporal and spatial features via balancing memory retention and dynamical response of individual layers. This approach paves the way for highly scalable hierarchical photonic reservoir computing systems for high-throughput real-time multimedia signal processing.

2605.30146 2026-05-29 math.AP cs.NA math.NA

Holographic X-ray Phase Contrast Imaging with Partial Coherence: Uniqueness and Reconstructions from Intensity Correlations

部分相干全息X射线相位衬度成像:强度相关性的唯一性与重建

Thorsten Hohage, Milad Karimi, Björn Müller

AI总结 研究部分相干光束下全息X射线成像中相位和吸收衬度的唯一可恢复性,提出利用低秩协方差算子的高效数值重建方法。

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AI中文摘要

全息相干X射线成像能够实现生物细胞和组织的纳米级成像,同时提供相位和吸收衬度,即折射率的实部和虚部。与假设完全相干入射光束的标准模型不同,我们考虑由已知协方差算子表征的部分相干性。此外,我们假设时间分辨的强度测量,不仅允许访问期望强度,还允许访问它们的相关性。我们研究了这些相关性的信息内容,并分析证明,在样品和照明区域的对称性破缺条件下,相位和吸收衬度可以在完整模型和线性化模型中唯一恢复。数值重建中的一个关键挑战是在预处理过程中计算强度相关性导致的数据维度大幅增加。我们提出了一种新方法,利用入射光束协方差算子的低秩假设,绕过显式相关性计算,同时利用其全部信息。数值实验证明了其可行性,实现了相位和吸收衬度的准确同时重建。

英文摘要

Holographic coherent X-ray imaging enables nanoscale imaging of biological cells and tissues, rendering both phase and absorption contrast, i.e. real and imaginary parts of the refractive index. Unlike the standard model, which assumes a perfectly coherent incident beam, we consider partial coherence characterized by a known covariance operator. In addition, we assume time-resolved intensity measurements, granting access not only to expected intensities but also to their correlations. We investigate the information content of these correlations and analytically demonstrate that, under a symmetry-breaking condition on the sample and the illumination area, both phase and absorption contrast can be uniquely recovered in both the full and the linearized models. A key challenge in numerical reconstruction is the substantial increase in data dimensionality caused by computing intensity correlations during preprocessing. We propose a novel approach that leverages a low-rank assumption on the incident beam covariance operator, bypassing explicit correlation computation while still exploiting its full information. Numerical experiments demonstrate its feasibility, yielding accurate simultaneous reconstructions of phase and absorption contrast.

2605.30145 2026-05-29 gr-qc astro-ph.CO astro-ph.GA

Supermassive black hole seeds from direct collapse of CDM-curvature peaks

从CDM-曲率峰直接坍缩形成的超大质量黑洞种子

Marco Galoppo, Marco Bruni, Tomohiro Harada

AI总结 利用完全非线性相对论框架,研究冷暗物质曲率峰直接坍缩形成超大质量黑洞种子,发现宽补偿曲率峰在红移大于5时形成10^3-10^6太阳质量的黑洞。

Comments 34 pages, 10 figures

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AI中文摘要

我们研究了物质主导时期原初扰动非线性增长和坍缩形成的黑洞(BH)。将冷暗物质(CDM)建模为无压尘埃,我们使用Lemaître-Tolman-Bondi(LTB)和准球对称Szekeres解作为空间平坦Friedmann-Lemaître-Robertson-Walker(FLRW)$Λ$CDM背景的精确扰动,在完全非线性相对论框架中描述坍缩。在相对论标量扰动理论的一阶,任何相关量的增长模式可以用守恒规范不变曲率扰动$\mathcal{R}_c$表示,该扰动作为垂直于物质4速度的超曲面的3曲率势。我们利用这一结果,将LTB和Szekeres模型中的活跃引力质量和曲率函数表示为$\mathcal{R}_c$及其空间导数的初始值。从这些初始曲率数据,我们推导出:(i)转向、坍缩和视界形成时间,以及(ii)黑洞形成所需的规则性条件。我们表明正弦和高斯轮廓不提供可行的黑洞形成通道,而由峰理论自然预测的宽补偿曲率峰则提供。然后,我们估计了由原初CDM曲率峰直接坍缩产生的$10^{3}-10^{6}~\mathrm{M}_\odot$大质量黑洞种子的形成时间,发现在红移$z>5$时完全形成黑洞,核心坍缩始于$10 \lesssim z \lesssim 16$。最后,我们直接从初始共动曲率数据表征坍缩的局部动力学和奇点类型(点状、雪茄状或薄饼状),阐明了初始剪切在选择坍缩终态中的作用。

英文摘要

We study black hole (BH) formation from the nonlinear growth and collapse of primordial perturbations during the matter-dominated era. Modelling cold dark matter (CDM) as pressureless dust, we describe the collapse in a fully nonlinear relativistic framework using the Lemaître-Tolman-Bondi (LTB) and quasi-spherical Szekeres solutions as exact perturbations of a spatially-flat Friedmann-Lemaître-Robertson-Walker (FLRW) $Λ$CDM background. At first order in relativistic scalar perturbation theory, the growing mode of any relevant quantity can be expressed in terms of the conserved gauge-invariant curvature perturbation $\mathcal{R}_c$, which acts as a potential for the 3-curvature of hypersurfaces orthogonal to the matter 4-velocity. We use this result to express the active gravitational mass and curvature functions of the LTB and Szekeres models in terms of the initial values of $\mathcal{R}_c$ and its spatial derivatives. From these initial curvature data we derive: (i) the turn-around, collapse, and apparent-horizon formation times, and (ii) the regularity conditions required for BH formation. We show that sinusoidal and Gaussian profiles do not provide viable BH-forming channels, whereas broad compensated curvature peaks, naturally predicted by peak theory, do. We then estimate the formation times of $10^{3}-10^{6}~\mathrm{M}_\odot$ massive BH seeds produced by the direct collapse of primordial CDM curvature peaks, finding full BH formation at redshifts $z>5$, with core collapse beginning at $10 \lesssim z \lesssim 16$. Finally, we characterize the local dynamics and singularity type of the collapse (point-like, cigar-like, or pancake-like) directly from the initial comoving curvature data, clarifying the role of the initial shear in selecting the collapse end-state.

2605.30143 2026-05-29 quant-ph

End-to-End Molecular Dynamics with a Langevin Thermostat on Quantum Circuits

基于量子电路的朗之万热浴分子动力学端到端实现

Masari Watanabe, Hirofumi Nishi, Taichi Kosugi, Shigekazu Hidaka, Ryo Sakurai, Yu-ichiro Matsushita

AI总结 提出一种在量子电路上实现正则系综(NVT)有限温度分子动力学的框架,通过Koopman-von Neumann波函数编码经典相空间分布,利用朗之万型Fokker-Planck弛豫制备正则态,并演示了振动态密度和过渡态理论速率常数的量子读出。

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AI中文摘要

我们构建了一个用于正则系综(NVT)中有限温度分子动力学的量子电路框架,该框架包含朗之万热浴,将正则态制备与后续物理性质读出连接起来。经典核相空间分布被编码为Koopman-von Neumann(KvN)波函数,正则态制备被表述为朗之万型Fokker-Planck弛豫。哈密顿量刘维尔流、动量摩擦和动量扩散被分解为独立的电路模块。摩擦模块由对称化的动量空间膨胀表示,而扩散模块通过概率虚时演化(PITE)实现的余弦滤波器实现。我们解析地量化了由PITE实现的余弦滤波器替代高斯扩散核引起的领先阶温度偏差。该分析产生了一个内部温度修正,以瞄准所需的物理平衡分布。作为连接量子化学与KvN核动力学的概念验证演示,我们研究了H$_2$分子。数值模拟显示从非平衡相空间分布弛豫到正则KvN态。从该正则态出发,我们演示了两种互补的读出:一种是与H-H伸缩坐标相关的振动态密度的动态量子相位估计读出,另一种是过渡态理论(TST)速率常数的静态正则评估。这项工作在一个最小分子系统中展示了连接朗之万正则态制备与物理性质计算的电路级协议,为量子计算机上的量子-经典混合分子动力学迈出了具体一步。

英文摘要

We construct a quantum-circuit framework for finite-temperature molecular dynamics in the canonical ensemble (NVT) with a Langevin thermostat, connecting canonical state preparation to subsequent physical-property readouts. The classical nuclear phase-space distribution is encoded as a Koopman--von Neumann (KvN) wave function, and canonical state preparation is formulated as Langevin-type Fokker--Planck relaxation. The Hamiltonian Liouville flow, momentum friction, and momentum diffusion are decomposed into separate circuit blocks. The friction block is represented by a symmetrized momentum-space dilation, whereas the diffusion block is implemented as a cosine filter realized by probabilistic imaginary-time evolution (PITE). We analytically quantify the leading-order temperature bias caused by replacing the Gaussian diffusion kernel with this PITE-realized cosine filter. This analysis yields an internal-temperature correction that targets the desired physical equilibrium distribution. As a proof-of-concept demonstration connecting quantum chemistry to KvN nuclear dynamics, we study the H$_2$ molecule. Numerical simulations show relaxation from a nonequilibrium phase-space distribution to a canonical KvN state. From this canonical state, we demonstrate two complementary readouts: a dynamical quantum-phase-estimation readout of the vibrational density of states associated with the H--H stretch coordinate and a static canonical evaluation of the transition-state-theory (TST) rate constant. This work demonstrates, in a minimal molecular system, a circuit-level protocol that connects Langevin canonical state preparation to physical-property calculations, providing a concrete step toward quantum--classical hybrid molecular dynamics on quantum computers.

2605.30142 2026-05-29 quant-ph

Koopman--von Neumann Molecular Dynamics for Green--Kubo Transport Coefficients

Koopman--von Neumann 分子动力学用于 Green--Kubo 输运系数

Masari Watanabe, Hirofumi Nishi, Taichi Kosugi, Shigekazu Hidaka, Ryo Sakurai, Yu-ichiro Matsushita

AI总结 本文利用 Koopman--von Neumann 表示将经典分子动力学的 Green--Kubo 输运系数表述为量子算法的读出问题,并分析了离散化误差和量子资源需求。

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AI中文摘要

我们利用 Koopman--von Neumann (KvN) 表示将经典分子动力学的 Green--Kubo 输运系数表述为量子算法的读出问题。NVE 和 Nosé--Hoover 型 NVT 动力学均被推导为与相应经典相空间相关的 Hilbert 空间上的酉演化。在有限网格上的数值基准测试表明,相关函数中的离散化误差随网格点数 $N_z$ 呈幂律下降。等价地,当 $N_z=2^{n_z}$ 时,误差随寄存器大小 $n_z$ 呈指数下降,因此目标精度 $ε$ 需要 $n_z=\mathcal{O}(\log(1/ε))$ 个量子比特。为了读出输运系数,我们将通量激发态输入到量子相位估计 (QPE) 中。测量 QPE 辅助寄存器全零态的概率 $P_0$ 对应于 Bartlett 窗 Green--Kubo 积分。通过最大似然振幅估计,由该 QPE 预言机定义的 $P_0$ 的统计估计从直接射击采样的 $N_{ m queries}^{-1/2}$ 标度改进为接近 $N_{ m queries}^{-1}$ 的标度。我们的电路资源分析表明,NVE 传播器的一步可以用 $\mathcal{O}(n^2)$ 个 CX 门构建,其中 $n=n_x+n_p$ 是位置和动量量子比特的总数。对于 NVT 传播器,Nosé--Hoover 摩擦项的中心差分 Pauli 分解实现标度为 $\mathcal{O}(n_ξn_p\,2^{n_p})$,其中 $n_p$ 和 $n_ξ$ 分别是动量和恒温器量子比特数。所提出的框架是将量子算法原理转化为实际分子模拟中所需的输运系数计算的具体步骤。

英文摘要

We formulate the Green--Kubo transport coefficients of classical molecular dynamics as a readout problem for quantum algorithms using the Koopman--von Neumann (KvN) representation. Both NVE and Nosé--Hoover-type NVT dynamics are derived as unitary evolutions on Hilbert spaces associated with the corresponding classical phase spaces. Numerical benchmarks on finite grids show that the discretization error in the correlation function decreases as a power law in the number of grid points $N_z$. Equivalently, with $N_z=2^{n_z}$, the error decreases exponentially in the register size $n_z$, so a target accuracy $ε$ requires $n_z=\mathcal{O}(\log(1/ε))$ qubits. To read out a transport coefficient, we input a flux-excited state to quantum phase estimation (QPE). The probability $P_0$ of measuring the QPE ancilla register in the all-zero state corresponds to a Bartlett-windowed Green--Kubo integral. With maximum-likelihood amplitude estimation, the statistical estimation of $P_0$ defined by this QPE oracle improves from the $N_{\rm queries}^{-1/2}$ scaling of direct shot sampling to scaling close to $N_{\rm queries}^{-1}$. Our circuit-resource analysis shows that one step of the NVE propagator can be built with $\mathcal{O}(n^2)$ CX gates, where $n=n_x+n_p$ is the total number of position and momentum qubits. For the NVT propagator, the centered-difference Pauli-decomposition implementation of the Nosé--Hoover friction term scales as $\mathcal{O}(n_ξn_p\,2^{n_p})$, where $n_p$ and $n_ξ$ are the numbers of momentum and thermostat qubits, respectively. The proposed framework is a concrete step toward translating the principles of quantum algorithms into the transport-coefficient calculations required in practical molecular simulation.

2605.30141 2026-05-29 quant-ph

Overcoming the Matrix-Product-State Encoding Barrier via DMRG-Guided Probabilistic Imaginary-Time Evolution

克服矩阵乘积态编码障碍:基于DMRG引导的概率虚时演化

Masari Watanabe, Hirofumi Nishi, Taichi Kosugi, Shinji Tsuneyuki, Yu-ichiro Matsushita

AI总结 提出一个三阶段框架,结合密度矩阵重整化群(DMRG)的经典预处理、无优化的矩阵乘积态编码电路和确定性调度的概率虚时演化(PITE),高效制备量子模拟中的基态。

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AI中文摘要

基态制备是量子模拟中的基本任务,因为制备态与真实基态的重叠显著影响后续量子算法的总成本。我们提出一个三阶段框架,其中通过密度矩阵重整化群(DMRG)获得的$N$位点系统的矩阵乘积态(MPS)通过无优化的矩阵乘积解纠缠器(MPD)编码电路加载到$N$量子比特量子寄存器上,然后通过概率虚时演化(PITE)减少残余误差。我们证明,MPS编码过程中中间态的中心键施密特秩随层数呈逻辑增长。其拐点$L^{*}$标志着高效编码区域的边界。超过该点,保真度增益迅速减慢,达到目标不保真度$\varepsilon$所需的额外MPD层数经验上标度为$\mathcal{O}(N^5\log(N/\varepsilon))$。为避免这种仅编码的尾部,我们在$L^{*}$处停止编码器,并通过PITE抑制剩余的激发态分量,其中线性PITE调度由DMRG估计的基态能量、有效能隙和参考重叠确定性固定。在自旋-$1/2$交错场海森堡链上的数值实验表明,该框架避免了非常深的编码电路,并显著抑制了PITE固有的后选择开销。结合DMRG的经典预处理、无优化的MPS编码和确定性调度的PITE,本框架为量子模拟中的基态制备提供了一条实用的混合路线。

英文摘要

Ground-state preparation is a fundamental task in quantum simulation, because the overlap of the prepared state with the true ground state significantly affects the overall cost of subsequent quantum algorithms. We propose a three-stage framework in which a matrix product state (MPS) of an $N$-site system obtained by the density-matrix renormalization group (DMRG) is loaded onto an $N$-qubit quantum register through an optimization-free matrix product disentangler (MPD) encoding circuit, and the residual error is then reduced by probabilistic imaginary-time evolution (PITE). We demonstrate that the central-bond Schmidt rank of intermediate states during MPS encoding grows logistically with the number of layers. Its inflection point $L^{*}$ marks the boundary of the efficient encoding regime. Beyond this point, the gain in fidelity slows rapidly, and the number of additional MPD layers required to reach a target infidelity $\varepsilon$ empirically scales as $\mathcal{O}(N^5\log(N/\varepsilon))$. To avoid this encoding-only tail, we stop the encoder at $L^{*}$ and suppress the remaining excited-state components by PITE, with the linear PITE schedule fixed deterministically from the ground-state energy, the effective gap, and the reference overlap estimated by DMRG. Numerical experiments on the spin-$1/2$ staggered-field Heisenberg chain show that the framework avoids very deep encoding circuits and substantially suppresses the post-selection overhead intrinsic to PITE. Combining classical preprocessing by DMRG, optimization-free MPS encoding, and deterministically scheduled PITE, the present framework offers a practical hybrid route to ground-state preparation in quantum simulation.

2605.30139 2026-05-29 astro-ph.CO gr-qc

Cosmo-PINN: A Physics-Informed Neural Network for Cosmological Reconstruction

Cosmo-PINN:一种用于宇宙学重建的物理信息神经网络

Andronikos Paliathanasis

AI总结 提出Cosmo-PINN,通过将物理约束嵌入损失函数,直接从晚期宇宙观测数据重建暗能量状态方程参数w_DE(z),克服了传统方法物理一致性不足的问题。

Comments 17 pages, 10 figures, comments are welcome

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AI中文摘要

我们引入了Cosmo-PINN,一种用于宇宙学理论重建的物理信息神经网络。在这项工作中,我们展示了Cosmo-PINN在直接从晚期宇宙观测数据重建暗能量状态方程参数$w_{DE}\left( z ight) $中的应用。该框架通过将宇宙学约束作为硬约束直接嵌入损失函数,确保重建量在训练过程中每一点都满足物理定律,从而克服了高斯过程和人工神经网络重建方法共有的主要局限性,即恢复解由数据驱动且不一定物理一致。对于网络的训练,我们使用了背景数据,具体包括DESI DR2的重子声学振荡、宇宙计时器和三个不同的超新星汇编,同时将宇宙学参数$H_{0},~Ω_{m0}$和$r_{\mathrm{drag}}$作为训练参数引入。重建结果显示,训练的$w_{DE}\left( z ight) $在红移范围$z=0.27-0.42$内穿过幻影分界线,与Chevallier-Polarski-Linder模型获得的值一致。在精粹场景中,对于大红移,暗能量$Ω_{DE}\left( z ight) $对宇宙流体提供了无压的非零贡献,暗示了一个统一场景。最后,我们通过将Cosmo-PINN重建与具有相同架构的纯数据驱动神经网络进行比较,证明了在损失函数中施加物理约束的重要性。

英文摘要

We introduce Cosmo-PINN, a Physics-Informed Neural Network for reconstruction of the cosmological theory. In this work we demonstrate the application of the Cosmo-PINN in the reconstruction of the dark energy equation of state parameter $w_{DE}\left( z\right) $ directly from late-time cosmological observations. This framework overcomes the main limitation shared by Gaussian Process and Artificial Neural Network reconstruction approaches, where the recovered solution is driven by the data and it is not necessarily true that it is physically consistent, by embedding the cosmological constraints directly into the loss function as hard constraints, ensuring that the reconstructed quantities satisfy the physical laws at every point during the training. For the training of the network, we employed background data, and specifically the Baryon Acoustic Oscillation from DESI DR2, the Cosmic Chronometers and three different Supernova compilations, while we simultaneously introduce the cosmological parameters $H_{0},~Ω_{m0}$ and $r_{\mathrm{drag}}$ as trained parameters. The reconstruction shows that the trained $w_{DE}\left( z\right) $ crosses the phantom divide within the redshift range $z=0.27-0.42$ in agreement with the value obtained by the Chevallier-Polarski-Linder model. In the quintessence scenario, for large redshifts the dark energy $Ω_{DE}\left( z\right) $ provides a pressureless nonzero contribution to the cosmological fluid suggesting a unified scenario. Finally, we demonstrate the significance of imposing the physical constraints within the loss function by comparing the Cosmo-PINN reconstruction against a purely data-driven neural network with the same architecture.

2605.30138 2026-05-29 math.GR math.LO

Residual properties of finitely generated groups in the Weihrauch lattice

Weihrauch格中有限生成群的剩余性质

Emmanuel Rauzy

AI总结 通过Weihrauch格量化映射Res_C的不连续性,并利用其位置刻画C的等式诺特性和剩余C群集是否为拟簇,给出了C为有限群、幂零群等情形下的精确分类。

Comments 38 pages

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AI中文摘要

考虑在标记群空间上,对于不同的群集合C,映射Res_C将标记群与其最大剩余-C商相关联。除平凡情况外,该映射是不连续的。我们使用Weihrauch格来量化其不连续程度。我们证明了C的等式诺特性以及剩余-C群集是否为拟簇都可以通过Res_C在Weihrauch格中的位置来刻画。我们给出了Res_C的精确分类,其中C分别为:有限群集、幂零群集、k-幂零群集(k≥1)、有限呈现群集、LEF群集、无挠群集。

英文摘要

Consider, on the space of marked groups, the map $\mathrm{Res}_{\mathcal{C}}$ which associates to a marked group its greatest residually-$\mathcal{C}$ quotient, for different sets $\mathcal{C}$ of groups. Except for trivial cases, this map is discontinuous. We use the Weihrauch lattice to quantify how discontinuous it is. We show that equational noetherianity of $\mathcal{C}$ and whether the set of residually-$\mathcal{C}$ groups is a quasivariety both can be characterized in terms of the position of $\mathrm{Res}_{\mathcal{C}}$ within the Weihrauch lattice. We give exact classifications of $\mathrm{Res}_{\mathcal{C}}$, for $\mathcal{C}$ one of: the set of finite groups, of nilpotent groups, of $k$-nilpotent groups, $k\ge1$, of finitely presentable groups, of LEF groups, of torsion free groups.

2605.30137 2026-05-29 cond-mat.mtrl-sci

Composition-dependent Thin-film Synthesis of Layered Ternary Iron Nitrides FeMN2 (M = W, Mo)

层状三元氮化铁FeMN2 (M = W, Mo)的成分依赖薄膜合成

Baptiste Julien, Liam A. V. Nagle-Cocco, Yuwei Yang, Nicholas A. Strange, Nicholas M. Bedford, Andriy Zakutayev

AI总结 通过反应溅射和NH3退火制备层状FeMN2薄膜,研究成分对相形成、织构及电磁性质的影响,发现FeWN2和FeMoN2存在不同的结构适应机制。

Comments 24 pages, 7 figures

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AI中文摘要

具有层状晶体结构的三元过渡金属氮化物具有各向异性键合和降低的维度,可能实现非常规的电子和磁行为。然而,此类氮化物薄膜的合成仍具挑战性,因为反应溅射通常倾向于亚稳态岩盐衍生结构。我们报道了通过反应溅射和沉积后NH3退火制备的具有三角Fe子晶格的层状FeMN2 (M = W, Mo)薄膜的成分依赖合成、结构和性质。利用同步辐射掠入射广角X射线散射(GIWAXS)和X射线吸收光谱(XAS),我们研究了相形成、晶体学织构和局部Fe配位随成分的演变。两种层状相在宽成分范围内形成。FeWN2在成分范围内保持高相纯度,与阳离子替代一致,而FeMoN2仅在贫Fe成分下表现出良好的相纯度。方位角GIWAXS分析显示,两种体系中的富Fe薄膜表现出面外纤维织构,在FeWN2中逐渐演变为近化学计量比时的面内取向,而FeMoN2则形成更随机取向的多晶微结构。电学测量显示FeWN2的电阻率相对较低且对成分不敏感(~1 mΩ·cm),而FeMoN2在名义化学计量比附近出现显著的电阻率最大值。FeWN2的初步室温磁化测量进一步显示,贫Fe薄膜表现出弱铁磁行为,而化学计量比成分仍主要为顺磁性。这些结果证明了FeWN2和FeMoN2中根本不同的结构适应机制,并强调了层状氮化物薄膜中成分、微结构与电子/磁性质之间的强耦合。

英文摘要

Ternary transition-metal nitrides with layered crystal structures host anisotropic bonding and reduced dimensionality that may enable unconventional electronic and magnetic behavior. Yet, synthesis of such nitride thin films remains challenging because reactive sputtering often favors metastable rocksalt-derived structures. We report the composition-dependent synthesis, structure, and properties of layered FeMN2 (M = W, Mo) thin films with triangular Fe sublattices, prepared by reactive sputtering and post-deposition NH3 annealing. Using synchrotron grazing-incidence wide-angle X-ray scattering (GIWAXS) and X-ray absorption spectroscopy (XAS), we investigate the evolution of phase formation, crystallographic texture, and local Fe coordination across composition. Both layered phase form over broad composition ranges. FeWN2 maintains high phase purity across compositions, consistent with cation substitution, whereas FeMoN2 only exhibits good phase purity at Fe-poor compositions. Azimuthal GIWAXS analysis shows that Fe-rich films in both systems exhibit out-of-plane fiber texture, which progressively evolves toward predominantly in-plane orientation near stoichiometry in FeWN2, while FeMoN2 develops a more randomly oriented polycrystalline microstructure. Electrical measurements reveal relatively low and composition-insensitive resistivity in FeWN2 (~1 mΩ.cm), whereas FeMoN2 exhibits a pronounced resistivity maximum near nominal stoichiometry. Preliminary room-temperature magnetization measurements on FeWN2 further reveal weak ferromagnetic-like behavior in Fe-poor films, while stoichiometric compositions remain predominantly paramagnetic. These results demonstrate fundamentally different structural accommodation mechanisms in FeWN2 and FeMoN2, and highlight the strong coupling between composition, microstructure, and electronic/magnetic properties in layered nitride thin films.

2605.30134 2026-05-29 stat.CO

Accurate and Efficient MCMC for Latent Position Models

潜在位置模型的精确高效MCMC

Zonghao Li, Aaron Smith

AI总结 针对潜在位置模型(LPM)的贝叶斯推断,提出两种MCMC算法:一种在几乎O(|E|)时间内运行且精度更高,另一种在几乎O(|V|)时间内运行且精度略有提升,主要创新是引入一种可廉价更新的辅助数据结构。

Comments 43 pages, 8 figures

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AI中文摘要

潜在位置模型(LPM)是一类广泛流行的随机图模型。然而,拟合贝叶斯LPM在计算上具有挑战性——即使只计算一次似然,所需时间也与观测图$G = (V,E)$的顶点数$|V|$呈二次关系。许多先前的工作引入了近似MCMC算法来加速,其中最接近我们的是Rastelli等人(2024),他们提出了一种算法,其摊销运行时间几乎可以降低到$O(|E|)$,并且在合理的推理问题上具有良好的实证表现。本文提供了两种解决同一问题的算法:一种“快速”算法,其运行时间与Rastelli等人相同,几乎为$O(|E|)$量级,但具有更强的精度保证;另一种“更快”算法,其运行时间改进为几乎$O(|V|)$,精度保证相比Rastelli等人略有提升(但不足以应对所有任务)。主要改进来自于引入一种简单的辅助数据结构,该结构可以在MCMC运行期间廉价地更新;我们怀疑这种“廉价草图”可能对其他MCMC算法也有用。

英文摘要

Latent position models (LPMs) are a large and popular class of models for random graphs. However, fitting Bayesian LPMs is computationally challenging - computing the likelihood even once takes time that is quadratic in the number of vertices $|V|$ of the observed graph $G = (V,E)$. Many previous papers have introduced approximate MCMC algorithms to speed this up, with the most similar to ours, Rastelli et al (2024), presenting an algorithm that has amortized running time that can be reduced almost to $O(|E|)$ and good empirical performance on reasonable inference problems. The present paper offers two algorithms for solving the same problem: a ``fast" algorithm with running time of the same almost-$O(|E|)$ order as astelli et al and much stronger accuracy guarantees, and a ``faster" algorithm with an improved running time of almost $O(|V|)$, and accuracy guarantees that are slightly improved compared to Rastelli et al (but not sufficient for all tasks). The main improvements come from the introduction of a simple auxiliary data structure that can be cheaply updated during an MCMC run; we suspect that the same ``cheap sketch" may be useful for other MCMC algorithms.

2605.30130 2026-05-29 cond-mat.mes-hall cond-mat.mtrl-sci

Carrier-coupled ultrafast structural dynamics and interlayer energy transport of supported transition metal dichalcogenide heterostructures

载体耦合的超快结构动力学与支撑过渡金属二硫族化物异质结构的层间能量传输

Md. Shaikot Alam Shakil, Ting-Hsuan Wu, Xing He, Abu Montakim Tareq, Zhenjia Zhou, Libo Gao, Naihao Chiang, Ding-Shyue Yang

AI总结 利用反射超快电子衍射直接观测支撑MoS2/WS2双层异质结构及其单层的光致面外结构动力学,揭示了层间电荷转移引发的载体耦合层内原子运动,并报告了不同能量流路径及热边界电导。

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AI中文摘要

理解层状二维异质结构中的电子耦合和能量流对于下一代光电器件中载流子和声子输运的利用以及热管理至关重要。通过使用反射超快电子衍射,我们直接研究了支撑的MoS2/WS2双层异质结构及其单层的光致面外结构动力学。实验证据揭示了由于跨范德华异质结的层间电荷转移而引发的超快载体耦合层内原子运动,这在单层中是不存在的。这种显著的载流子-晶格相关性是对异质结构增强光学吸收所体现的电子耦合的补充。此外,还报告了由于载流子-声子耦合和声子散射产生的不同能量流路径及其相应的特征时间。在更长的时间尺度上,热化原子运动的弛豫可以用热传输模型充分描述。与单层-基底界面相比,MoS2/WS2异质结构获得了更高的热边界电导;然而,相似的热边界电导值表明跨范德华接触的声子耦合相当。这些结果进一步揭示了垂直堆叠范德华异质结构的光学、声子和界面热性质。

英文摘要

Understanding the electronic coupling and energy flow across layered two-dimensional heterostructures (HSs) is crucial to the exploitation of carrier and phonon transports as well as thermal management in next-generation optoelectronic devices. By using reflection ultrafast electron diffraction, we directly examine photoinduced out-of-plane structural dynamics of supported MoS2/WS2 bilayer HSs and their individual monolayers. Experimental evidence reveals the launch of ultrafast carrier-coupled intralayer atomic motions due to interlayer charge transfer across the van der Waals (vdW) heterojunctions that is absent for individual monolayers. Such a notable carrier-lattice correlation is in addition to the electronic coupling manifested in the enhanced optical absorption for HSs. Also, different pathways of energy flow as a result of carrier-phonon coupling and phonon scattering are reported with the corresponding characteristic times. On longer timescales, relaxation of thermalized atomic motions can be sufficiently described by a thermal transport model. A higher thermal boundary conductance (TBC) across MoS2/WS2 HSs is obtained compared to those at the monolayer-substrate interfaces; however, the similar TBC values suggest comparable couplings of phonons across vdW contacts. These results further shed light on the optical, phonon, and interfacial thermal properties of vertically-stacked vdW HSs.

2605.30129 2026-05-29 cond-mat.mes-hall

Engineering Quantum Criticality in the Integer Quantum Hall Regime through a Screening Layer

通过屏蔽层在整数量子霍尔体系中工程化量子临界性

C. T. Tai, P. T. Madathil, A. Gupta, L. N. Pfeiffer, K. W. Baldwin, M. Shayegan

AI总结 利用GaAs双量子阱器件中的双层电子系统,通过调控顶层电子密度实现底层库仑相互作用的原位屏蔽,发现屏蔽使临界指数k从0.42降至0.22,对应动力学指数z从1变为2,直接实验证明了电子-电子相互作用在量子霍尔临界行为中的决定性作用。

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AI中文摘要

无序诱导的电子局域化和电子-电子相互作用是凝聚态物理中最基本的问题之一。在二维电子系统中,广泛研究导致了一个标度图像的建立,其特征是一组普适的临界指数,控制着整数量子霍尔平台之间的转变。从平台到平台转变的温度依赖性来看,实验主要报告k ~ 0.42,这意味着动力学指数z = 1,与电子具有长程(1/r)相互作用的理论图像一致。理论还预测,对于短程电子相互作用,z = 2,但实验验证一直难以实现。在这里,我们使用限制在GaAs双量子阱器件中的双层电子系统直接探测库仑相互作用对这些转变的影响。两层非常接近,层间距离大约等于相关磁场下的磁长度。通过调节顶层的电子密度,我们能够访问该层电子随磁场变化的绝缘相和金属相,从而在原位控制底层经历其平台到平台转变时未屏蔽和屏蔽的相互作用强度。在未屏蔽的情况下,我们测量到k ~ 0.42,与广泛报道的值一致。更重要的是,当引入屏蔽时,k降低到约0.22,意味着z = 2。我们的结果为电子-电子相互作用在决定量子霍尔体系中临界行为的作用提供了直接实验证据,并展示了屏蔽作为工程化量子临界性的强大调控参数。

英文摘要

Disorder-induced localization of electrons and electron-electron interaction are among the most fundamental problems in condensed matter physics. In two-dimensional electron systems, extensive studies have led to the emergence of a scaling picture, characterized by a set of universal critical exponents that govern the transitions between the integer quantum Hall plateaus. From the temperature dependence of the plateau-to-plateau transitions, experiments primarily report k ~ 0.42, implying a dynamic exponent z = 1, consistent with a theoretical picture where electrons have a long-range (1/r) interaction. Theory also predicts that z = 2 for short-range electron interaction, but an experimental verification has remained elusive. Here, we directly probe the influence of Coulomb interaction on these transitions using a bilayer electron system confined to a GaAs double quantum well device. The two layers are in close proximity, with an interlayer distance approximately equal to the magnetic length at the relevant magnetic fields. By tuning the electron density in the top layer, we access both insulating and metallic phases of the electrons in this layer as a function of magnetic field, allowing in-situ control of the unscreened and screened interaction strengths in the bottom layer as it goes through its plateau-to-plateau transitions. In the unscreened case, we measure k ~ 0.42 consistent with the widely reported value. More importantly, when screening is introduced, k is reduced to ~ 0.22, implying z = 2. Our results provide direct experimental evidence for the role of electron-electron interaction in determining critical behavior in the quantum Hall regime, and demonstrate screening as a powerful tuning parameter for engineering quantum criticality.

2605.30128 2026-05-29 cond-mat.mtrl-sci

Towards exascale fully relativistic pseudopotential density functional theory calculations enabled by mixed-precision computation and compressed-communication using residual based subspace iteration

迈向基于混合精度计算和残差子空间迭代压缩通信的百亿亿次全相对论赝势密度泛函理论计算

Nikhil Kodali, Gourab Panigrahi, Nishant Gupta, Kartick Ramakrishnan, Sundaresan G, Rudra Panch, Sambit Das, Vishwas Rao, Phani Motamarri

AI总结 针对非共线磁性和自旋轨道耦合带来的计算挑战,提出结合残差Chebyshev滤波子空间迭代、混合精度计算和压缩通信的GPU高性能框架,实现百亿亿次规模的全相对论赝势DFT模拟。

Comments 12 pages, 7 figures

详情
AI中文摘要

非共线(NC)磁性和自旋轨道耦合(SOC)对于具有显著相对论效应和磁挫折的预测性从头算材料模拟不可或缺,然而它们通过引入每个电子的复杂二分量波函数以及随之而来的更大特征问题,显著增加了立方标度密度泛函理论(DFT)的成本。我们提出了一个以GPU为中心的高性能NC-SOC DFT框架,该框架结合了:(i)求解有限元(FE)离散化DFT方程的算法进展;(ii)基于残差的Chebyshev滤波子空间迭代(R-ChFSI),对不精确的矩阵-向量积具有容忍性,用于求解得到的稀疏广义特征问题;(iii)加速FE泊松求解器的无矩阵策略;(iv)R-ChFSI支持的混合精度计算,配合压缩比超过4倍的块浮点压缩MPI通信,在降低计算和数据移动成本的同时保持双精度鲁棒性;以及(v)一种通信高效的能带划分算法以提高可扩展性。数值结果表明,在百亿亿次架构上实现了改进的求解时间和出色的可扩展性,使得能够对多达100,000个电子进行全相对论赝势DFT模拟。

英文摘要

Noncollinear (NC) magnetism and spin-orbit coupling (SOC) are indispensable for predictive ab initio materials simulations with pronounced relativistic effects and magnetic frustration, yet they significantly increase the cost of cubic-scaling density functional theory (DFT) by introducing complex 2-component wavefunctions per electron and consequently much larger eigenproblems. We present a GPU-centric high-performance framework for NC-SOC DFT that combines: (i) algorithmic advances for solving finite-element (FE) discretized DFT equations; (ii) residual-based Chebyshev filtered subspace iteration (R-ChFSI), tolerant to inexact matrix-vector products, for the resulting sparse generalized eigenproblem; (iii) a matrix-free strategy for accelerating FE Poisson solver; (iv) R-ChFSI-enabled mixed-precision computation with block floating-point compressed MPI communication at compression ratios over 4x, preserving double-precision robustness while reducing compute and data movement costs; and (v) a communication efficient band-partitioning algorithm to improve scalability. Numerical results demonstrate improved time-to-solution and excellent scaling on exascale architectures, enabling fully relativistic pseudopotential DFT simulations of up to 100,000 electrons.

2605.30127 2026-05-29 cs.HC eess.SP

REACT: A Conditioning Framework for User-Adaptive sEMG Hand Pose Estimation

REACT: 一种用于用户自适应sEMG手势姿态估计的条件框架

Eric Xie, Hei Shing Cheung

AI总结 提出REACT框架,通过轻量级条件机制和特征线性调制(FiLM)在推理时利用少量校准数据个性化预训练模型,实现跨用户sEMG手势姿态估计,在EMG2POSE基准上降低角度误差达3.9%。

Comments 6 pages, 3 figures

详情
AI中文摘要

表面肌电图(sEMG)能够在可穿戴设备上实现连续的手势姿态估计,但由于解剖结构和电极放置的个体间差异,基于多用户语料库训练的模型在未见过的个体上性能下降。我们提出了REACT,一个轻量级条件框架,在推理时仅使用少量校准记录即可个性化冻结的预训练EMG到姿态骨干网络。REACT从校准数据中学习紧凑的用户嵌入,并应用特征线性调制(FiLM)来适应共享编码器的特征空间,部署时无需梯度更新。在大型EMG2POSE基准上,REACT在回归和跟踪模式下所有三个泛化分割上均优于最先进的基线,在最小参数开销和每次用户校准时间低于45秒的情况下,将角度误差降低高达3.9%。

英文摘要

Surface electromyography (sEMG) enables continuous hand pose estimation on wearable devices, but models trained on multi-user corpora degrade on unseen individuals due to inter-user variability in anatomy and electrode placement. We propose REACT, a lightweight conditioning framework that personalizes a frozen pretrained EMG-to-pose backbone at inference time using only a handful of calibration recordings. REACT learns a compact user embedding from calibration data and applies Feature-wise Linear Modulation (FiLM) to adapt the shared encoder's feature space, requiring no gradient updates at deployment. On the large-scale EMG2POSE benchmark, REACT improves over the state-of-the-art baseline across all three generalization splits in both regression and tracking modes, reducing angular error by up to 3.9% with minimal parameter overhead and under 45 seconds of per-user calibration.