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0910.1018 2026-06-03 math.NA cs.NA

Uniform estimates for transmission problems with high contrast in heat conduction and electromagnetism

热传导和电磁学中高对比度传输问题的均匀估计

Gabriel Caloz, Monique Dauge, Victor Péron

AI总结 本文针对两个子域上常系数传输问题,特别关注系数比很大时的情况,通过收敛渐近级数处理标量传输问题,并基于电场分解推导麦克斯韦传输问题的均匀先验估计,应用于电导率趋于无穷时渐近展开的收敛性论证。

Journal ref J. Math. Anal. Appl. 370 (2010), no. 2, 555-572

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AI中文摘要

在本文中,我们证明了两个子域上常系数传输问题的均匀先验估计,特别强调这些系数之比很大时的情况。在大部分工作中,假设两个子域之间的界面是Lipschitz的。我们首先研究一个标量传输问题,通过收敛的渐近级数处理。然后,我们推导了在由电介质和高导电材料组成的域上设置的麦克斯韦传输问题的均匀先验估计。该技术基于电场的适当分解,其梯度部分通过第一部分进行估计。作为应用,我们为电导率趋于无穷时渐近展开的收敛性发展了一个论证。

英文摘要

In this paper we prove uniform a priori estimates for transmission problems with constant coefficients on two subdomains, with a special emphasis for the case when the ratio between these coefficients is large. In the most part of the work, the interface between the two subdomains is supposed to be Lipschitz. We first study a scalar transmission problem which is handled through a converging asymptotic series. Then we derive uniform a priori estimates for Maxwell transmission problem set on a domain made up of a dielectric and a highly conducting material. The technique is based on an appropriate decomposition of the electric field, whose gradient part is estimated thanks to the first part. As an application, we develop an argument for the convergence of an asymptotic expansion as the conductivity tends to infinity.

0909.5079 2026-06-03 math.NA cs.NA

Discrete compactness for the p-version of discrete differential forms

离散微分形式的p版本离散紧致性

Daniele Boffi, Martin Costabel, Monique Dauge, Leszek Demkowicz, Ralf Hiptmair

AI总结 本文证明了两维和三维空间中非椭圆变分特征值问题的p版本有限元逼近的离散紧致性,通过引入光滑Poincaré提升算子,为任意阶离散微分形式建立了广义离散紧致性的充分条件,并验证了多种常用边缘有限元族满足该性质。

Journal ref SIAM J. Numer. Anal. 49 (2011), no. 1, 135-158

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AI中文摘要

本文证明了两维和三维空间中一类广泛的非椭圆变分特征值问题的p版本有限元逼近的离散紧致性。在一个非常一般的框架下,我们找到了p版本广义离散紧致性的充分条件,该条件是在d维多面体域上任意阶离散微分形式的设定下表述的。分析的主要工具之一是最近引入的光滑Poincaré提升算子[M. Costabel and A. McIntosh, On Bogovskii and regularized Poincaré integral operators for de Rham complexes on Lipschitz domains, Math. Z., (2010)]。对于1阶形式,我们的分析表明,几个广泛使用的边缘有限元族在p版本下满足离散紧致性,从而为Maxwell特征值问题提供收敛解。特别地,我们的理论涵盖了三角形和四面体上的Nédélec元(第一类和第二类)以及平行四边形和平行六面体上的Nédélec元(第一类)。

英文摘要

In this paper we prove the discrete compactness property for a wide class of p-version finite element approximations of non-elliptic variational eigenvalue problems in two and three space dimensions. In a very general framework, we find sufficient conditions for the p-version of a generalized discrete compactness property, which is formulated in the setting of discrete differential forms of any order on a d-dimensional polyhedral domain. One of the main tools for the analysis is a recently introduced smoothed Poincaré lifting operator [M. Costabel and A. McIntosh, On Bogovskii and regularized Poincaré integral operators for de Rham complexes on Lipschitz domains, Math. Z., (2010)]. For forms of order 1 our analysis shows that several widely used families of edge finite elements satisfy the discrete compactness property in p-version and hence provide convergent solutions to the Maxwell eigenvalue problem. In particular, Nédélec elements on triangles and tetrahedra (first and second kind) and on parallelograms and parallelepipeds (first kind) are covered by our theory.

2507.16939 2026-06-03 quant-ph

Exact distinguishability between real-valued and complex-valued Haar random quantum states

实值与复值 Haar 随机量子态之间的精确可区分性

Tristan Nemoz, Romain Alléaume, Peter Brown

AI总结 通过解析计算正交群 Haar 随机态 t 副本密度矩阵的谱分解,精确计算实与复 Haar 随机态 t 副本的迹距离,从而给出实值态 t-设计的近似参数下界并改进虚数性测试所需副本数的下界。

Comments 16+29 pages

Journal ref Quantum 10, 2120 (2026)

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AI中文摘要

Haar 随机态是量子信息理论和量子计算中的基本对象。我们研究根据正交群上的 Haar 测度采样 $t$ 个 $d$ 维量子态副本得到的密度矩阵。特别地,我们解析计算了其谱分解。这使我们能够精确计算实 Haar 随机态的 $t$ 副本与复 Haar 随机态的 $t$ 副本之间的迹距离。利用这一点,我们给出了实值态 $t$-设计的近似参数的下界,并改进了虚数性测试所需副本数的下界。

英文摘要

Haar random states are fundamental objects in quantum information theory and quantum computing. We study the density matrix resulting from sampling $t$ copies of a $d$-dimensional quantum state according to the Haar measure on the orthogonal group. In particular, we analytically compute its spectral decomposition. This allows us to compute exactly the trace distance between $t$-copies of a real Haar random state and $t$-copies of a complex Haar random state. Using this we show a lower-bound on the approximation parameter of real-valued state $t$-designs and improve the lower-bound on the number of copies required for imaginarity testing.

2507.16512 2026-06-03 gr-qc

Semi-Analytic Trajectory Analysis of Light in Generic Static Spacetimes

一般静态时空中光的半解析轨迹分析

Ali Övgün, Reggie C. Pantig

AI总结 提出一个统一的半解析框架,通过同伦摄动法、变分迭代法和脉冲近似法研究一般静态球对称时空中的零测地线和弱场光偏折,并应用于标量毛Reissner-Nordström黑洞,比较三种方法的精度和收敛性。

Comments 23 pages

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AI中文摘要

我们研究了一个统一的半解析框架,用于研究一般静态、球对称时空中的零测地线和弱场光偏折,该时空度规形式为 \(ds^2 = -α(r,δ)\,dt^2 + γ(r,δ)\,dr^2 + β(r,δ)\,dΩ_2^2\),其中 \(α\)、\(β\) 和 \(γ\) 编码了源自 [Phys.Rev.D 112 (2025) 12, 124072] 的与史瓦西引力模型相关的偏离。从精确的一阶轨道方程出发,我们推导了一个紧凑的关于冲击参数依赖的轨迹 \(u(φ)\equiv 1/r(φ)\) 的主方程,并得到了用通用度规函数及其导数表示的偏折角 \(α(b)\) 的模型无关表达式。然后通过三种互补技术半解析地求解该主方程:(i) 同伦摄动法 (HPM),(ii) 变分迭代法 (VIM),以及 (iii) 直接用有效引力势表示的校准脉冲(单次冲击)近似。作为非平凡测试平台,我们考虑了一个类似标量毛Reissner-Nordström的黑洞,其中标量毛以有效电荷参数 \(Q_s\) 的形式出现。然后我们推导了偏折角的闭合形式表达式,识别了主导的标量毛贡献,并比较了 HPM、VIM 和脉冲方法相对于标准史瓦西极限的精度和收敛性质。我们的结果表明,在 \((α,β,γ)\) 中的通用公式可以有效地容纳一大类修正引力黑洞解。我们进一步通过紧致的数值结果补充了解析处理,该结果针对光子球附近的精确零测地线积分,以界定三种近似方案的实际有效范围。

英文摘要

We study a unified semi-analytical framework to study null geodesics and weak-field light deflection in generic static, spherically symmetric spacetimes of the form \(ds^2 = -α(r,δ)\,dt^2 + γ(r,δ)\,dr^2 + β(r,δ)\,dΩ_2^2,\) where $α$, $β$, and $γ$ encode model-dependent deviations from Schwarzschild gravity inspired from [Phys.Rev.D 112 (2025) 12, 124072]. Starting from the exact first-order orbit equation, we derive a compact master equation for the impact-parameter-dependent trajectory $u(φ)\equiv 1/r(φ)$ and obtain a model-independent expression for the bending angle $α(b)$ in terms of generic metric functions and their derivatives. This master equation is then solved semi-analytically by three complementary techniques: (i) the homotopy perturbation method (HPM), (ii) the variational iteration method (VIM), and (iii) a calibrated impulse (single-kick) approximation expressed directly in terms of the effective gravitational potential. As nontrivial test beds we consider a scalar-hairy Reissner-Nordström-like black hole where the scalar hair enters as $Q_s$ in an effective charge parameter. Then we derive closed-form expressions for the deflection angle, identify the leading scalar-hair, and compare the accuracy and convergence properties of HPM, VIM, and the impulse method against the standard Schwarzschild limits. Our results show that the generic formulation in $(α,β,γ)$ can efficiently accommodate a broad class of modified gravity black hole solutions. We further supplement the analytic treatment with a compact numerical results against the exact null-geodesic integral near the photon sphere in order to delineate the practical range of validity of the three approximation schemes.

2407.10082 2026-06-03 math.AG math.DG math.SG

On the blow-up formula of the Chow weights for polarized toric manifolds

关于极化环流形Chow权的爆破公式

King Leung Lee, Naoto Yotsutani

AI总结 通过组合公式将环流形在环面不动点爆破后的Chow权用原流形及其Delzant多面体的辛切割表示,并应用于射影平面的环面爆破与一般点爆破的Chow稳定性比较。

Comments Third version (21 pages): We have stated the precise relationship between the toric Chow weights used in this paper and the general algebro-geometric notion of Chow stability. In addition, we have clarified that Proposition 2.3 applies to certain specialized cases

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AI中文摘要

设$X$是一个光滑射影环簇,$\widetilde{X}$表示$X$在有限个不同的环面不变点处的爆破。本文推导了$\widetilde{X}$的Chow权的一个显式组合公式,该公式用底层环流形$X$及其关联的Delzant多面体的辛切割表示。作为应用,我们研究了射影平面的环面爆破,并将其Chow稳定性与一般点爆破的Chow稳定性进行了比较。

英文摘要

Let $X$ be a smooth projective toric variety, and let $\widetilde{X}$ denote the blow-up of $X$ at finitely many distinct torus-invariant points. In this paper, we derive an explicit combinatorial formula for the Chow weight of $\widetilde{X}$ in terms of the underlying toric manifold $X$ and the symplectic cuts of its associated Delzant polytope. As an application, we study toric blow-ups of the projective plane and compare their Chow stability with that of blow-ups at general points.

2507.13724 2026-06-03 quant-ph math-ph math.MP

Solving wave equation problems on D-Wave quantum annealers

在D-Wave量子退火器上求解波动方程问题

Aigerim Bazarkhanova, Alejandro J. Castro, Antonio A. Valido

AI总结 采用伪谱框架,在D-Wave量子退火器上求解一维亥姆霍兹方程,通过评估不同编码策略的代数条件和绝热性能,证明了降低动态范围的全秩矩阵编码能提升量子退火器性能,并讨论了混合量子-经典方案的潜力。

Comments 20+2 pages, 7 figures. Figures has been improved. Main text has been slightly modified. Accepted for publication in Quantum Information Processing. Comments are welcome

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AI中文摘要

我们在伪谱框架下,使用D-Wave Systems提供的量子退火器求解了多种场景下的一维亥姆霍兹方程,其中解被编码在适当的基函数集合中。我们基于代数条件和绝热考虑评估了不同编码策略的性能,并将其性能与经典模拟退火算法进行了基准测试。特别地,我们分析了最小能隙、所谓的动态范围和均方误差,以评估每种策略返回的数值稳定性、一致性和准确性。我们的工作强调了开发确保良好代数条件的自定义嵌入技术的重要性。特别是,我们表明,即使在多色驱动和非平凡初始条件下,产生具有降低动态范围的全秩矩阵的编码策略也能增强量子退火器的性能。我们进一步讨论了开发旨在同时满足代数条件和绝热要求的混合量子-经典方案的潜力。

英文摘要

We solve the one-dimensional Helmholtz equation in several scenarios using the quantum annealer provided by D-Wave Systems within a pseudospectral framework, where the solution is encoded in an appropriate set of basis functions. We evaluate the performance of different encoding strategies based on algebraic conditioning and adiabatic considerations, and benchmark their performance against the classical simulated annealing algorithm. In particular, we analyze the minimum energy gap, the so-called dynamic range, and the mean squared error to assess the numerical stability, consistency, and accuracy of the solutions returned by each strategy. Our work highlights the importance of developing custom embedding techniques ensuring well-conditioned algebraic systems. In particular, we show that encoding strategies producing full-rank matrices with reduced dynamic ranges enhance the performance of the quantum annealer even under polychromatic driving and nontrivial initial conditions. We further discuss the potential of developing hybrid quantum-classical schemes designed to simultaneously satisfy algebraic conditioning and adiabatic requirements.

2507.12603 2026-06-03 quant-ph

Qrisp Implementation and Resource Analysis of a T-Count-Optimised Non-Restoring Quantum Square-Root Circuit

基于Qrisp的T计数优化非恢复型量子平方根电路的实现与资源分析

Heorhi Kupryianau, Marcin Niemiec

AI总结 本文使用Qrisp量子编程框架首次完整实现了T计数优化的非恢复型量子平方根算法,验证了理论资源估计,并展示了资源优化量子算术算法的实际可行性。

Comments The paper under review

Journal ref Extended version of this article was published in Electronics journal in 2026

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AI中文摘要

高效的量子算术运算是复杂量子算法的基本构建块,然而很少有理论设计在实际的量子编程框架中实现。本文使用Qrisp量子编程框架首次完整实现了T计数优化的非恢复型量子平方根算法。该算法最初由Thapliyal等人提出,相比其他方法具有更好的资源效率,实现了更低的T计数和量子比特需求,同时避免了垃圾输出。我们的实现验证了理论资源估计,确认了对于n位输入,T计数为14n-14,T深度为5n+3。Qrisp支持的模块化设计方法允许从可重用组件构建电路,这些组件包括可逆加法器、减法器和由基本量子门构建的条件逻辑块。三阶段算法——包括初始减法、迭代条件加/减和余数恢复——成功从算法描述转换为可执行量子代码。跨多个测试用例的实验验证确认了正确性,电路产生准确的整数平方根和余数。这项工作证明了资源优化量子算术算法的实际可实现性,并为在现代量子编程框架中实现不同算术运算奠定了基础。

英文摘要

Efficient quantum arithmetic operations are essential building blocks for complex quantum algorithms, yet few theoretical designs have been implemented in practical quantum programming frameworks. This paper presents the first complete implementation of the T-count optimized non-restoring quantum square root algorithm using the Qrisp quantum programming framework. The algorithm, originally proposed by Thapliyal et al., offers better resource efficiency compared to alternative methods, achieving reduced T-count and qubit requirements while avoiding garbage output. Our implementation validates the theoretical resource estimates, confirming a T-count of 14n-14 and T-depth of 5n+3 for n-bit inputs. The modular design approach enabled by Qrisp allows construction from reusable components including reversible adders, subtractors, and conditional logic blocks built from fundamental quantum gates. The three-stage algorithm - comprising initial subtraction, iterative conditional addition/subtraction, and remainder restoration is successfully translated from algorithmic description to executable quantum code. Experimental validation across multiple test cases confirms correctness, with the circuit producing accurate integer square roots and remainders. This work demonstrates the practical realizability of resource-optimized quantum arithmetic algorithms and establishes a foundation for implementing different arithmetic operations in modern quantum programming frameworks.

2507.10857 2026-06-03 astro-ph.CO

CHEX-MATE: Cluster Multi-Probes in Three Dimensions (CLUMP-3D) II. Combined Gas and Dark Matter Analysis from X-ray, SZE, and WL

CHEX-MATE: 星系团三维多探针联合分析 (CLUMP-3D) II. 基于X射线、SZ效应和弱引力透镜的气体和暗物质联合分析

Adriana Gavidia, Junhan Kim, Jack Sayers, Mauro Sereno, Loris Chappuis, Dominique Eckert, Keiichi Umetsu, Herve Bourdin, Federico De Luca, Stefano Ettori, Massimo Gaspari, Raphael Gavazzi, Scott Kay, Lorenzo Lovisari, Pasquale Mazzotta, Gabriel Pratt, Elena Rasia, Mariachiara Rossetti

AI总结 针对球对称模型在星系团分析中引入的偏差,提出基于X射线、SZ和弱引力透镜数据的三轴椭球多探针拟合方法,应用于Abell 1689团,发现其沿视线方向拉伸,弱引力透镜质量比球对称拟合低约30%,并测量了非热压比例。

Journal ref A&A 710, A40 (2026)

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AI中文摘要

在等级结构形成的标准模型下,星系团的整体几何形状更适合用三轴椭球而非球体描述。因此,应用球对称模型可能导致显著偏差。这些偏差可以通过拟合三轴模型来缓解,这需要深度多探针数据和一组物理动机模型来描述它们。本文基于XMM-Newton的星系团遗产项目——结构形成终点的质量组装与热力学(CHEX-MATE)中可用的星系团数据,提出了一种多探针三轴分析方法,数据包括XMM-Newton的X射线数据、Planck和ACT的SZ数据以及Subaru的弱引力透镜数据。本工作建立在先前仅基于X射线和SZ的气体三轴拟合形式(论文I)的基础上。我们将该方法应用于CHEX-MATE星系团PSZ2 G313.33+61.13(Abell 1689),发现其沿视线方向相对于天球平面拉长,因子为$\mathcal{R}_{LP} = 1.27 \pm 0.02$。因此,从三轴拟合得到的弱引力透镜质量$ ext{M}_{200c}=(13.69_{-1.41}^{+1.56}) imes10^{14} ext{M}_{\odot}$显著低于采用相同方法的球对称拟合值$(17.77_{-1.75}^{+2.00}) imes10^{14} ext{M}_{\odot}$。我们的三轴拟合得到的浓度$c_{200c}=8.55_{-1.61}^{+2.20}$与球对称值$9.99_{-1.78}^{+2.26}$一致,这表明Abell 1689中意外高的浓度并非由三轴性和取向导致。我们还测量了0.18-1.37 Mpc半径范围内的非热压比例,发现在中间半径处最小约20%,在最小和最大半径处增加到近30%,典型测量精度为$\pm$5%。

英文摘要

Under the standard model of hierarchical structure formation, the overall geometry of galaxy clusters is better described by a triaxial ellipse than a sphere. As a result, applying spherically-symmetric models can result in significant biases. These biases can be mitigated by fitting a triaxial model, requiring deep multiprobe data and a set of physically motivated models to describe them. Here we present a multiprobe triaxial analysis methodology based on the data available for galaxy clusters in the Cluster Heritage project with XMM-Newton - Mass Assembly and Thermodynamics at Endpoint of structure formation (CHEX-MATE), which includes X-ray data from XMM-Newton, SZ data from Planck and ACT, and WL data from Subaru. This work builds on our previous development of a gas-only X-ray and SZ triaxial fitting formalism in Paper I. We apply our approach to the CHEX-MATE cluster PSZ2 G313.33+61.13 (Abell 1689) and find that it is elongated along the line of sight relative to the plane of sky by a factor of $\mathcal{R}_{LP} = 1.27 \pm 0.02$. As a result, the WL mass obtained from our triaxial fit, $\text{M}_{200c}=(13.69_{-1.41}^{+1.56})\times10^{14} \text{M}_{\odot}$, is significantly lower than the value of $(17.77_{-1.75}^{+2.00})\times10^{14} \text{M}_{\odot}$ obtained from a spherically-symmetric fit that otherwise employs the same methodology. Our triaxial fit finds a concentration of $c_{200c}=8.55_{-1.61}^{+2.20}$, consistent with the spherically-symmetric value of $9.99_{-1.78}^{+2.26}$, which suggests that the unexpectedly high concentration in Abell 1689 is not due to triaxiality and orientation. We also measure the non-thermal pressure fraction at radii between 0.18-1.37 Mpc, finding a minimum of approximately 20 per cent at intermediate radii increasing to near 30 per cent at both the smallest and largest radii, and with a typical measurement precision of $\pm$5 per cent.

2507.08852 2026-06-03 physics.chem-ph

Open, Reproducible Calculation of Assembly Indices

开放、可复现的组装指数计算

Devansh Vimal, Garrett Parzych, Olivia M. Smith, Devendra Parkar, Sean Bergen, Joshua J. Daymude, Cole Mathis

AI总结 本文介绍了一个用于计算共价键分子结构组装指数的Rust软件包assembly-theory,提供了高性能算法实现、基准测试和Python接口,以支持组装理论在化学等领域的应用。

Comments 8 pages, 2 figures, 1 table

Journal ref Journal of Open Source Software (2026) 11:117, 9318

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AI中文摘要

我们提出了assembly-theory,一个用于计算共价键分子结构组装指数的Rust软件包。这是组装理论中的一个关键复杂度度量,组装理论是一个最近的理论框架,用于量化跨不同系统(最重要的是化学)的选择。assembly-theory专为研究人员和从业者设计,提供(i)可扩展、高性能的组装指数计算算法实现,(ii)全面的基准测试,可用于测试当前和未来的算法改进,以及(iii)Python绑定和RDKit兼容的数据加载器,以支持与现有计算管道的集成。

英文摘要

We present assembly-theory, a Rust package for computing assembly indices of covalently bonded molecular structures. This is a key complexity measure of assembly theory, a recent theoretical framework quantifying selection across diverse systems, most importantly chemistry. assembly-theory is designed for researchers and practitioners alike, providing (i) extensible, high-performance implementations of assembly index calculation algorithms, (ii) comprehensive benchmarks against which current and future algorithmic improvements can be tested, and (iii) Python bindings and RDKit-compatible data loaders to support integration with existing computational pipelines.

2507.04853 2026-06-03 physics.flu-dyn cond-mat.stat-mech

Numerical search for states with constant enstrophy flux over finite time intervals in two-dimensional turbulence

二维湍流中有限时间间隔内恒定涡度通量状态的数值搜索

Kyo Yoshida

AI总结 采用蒙特卡洛方法数值搜索二维湍流中有限时间间隔内波数空间具有恒定涡度通量的状态,并检验其能谱等性质与直接数值模拟湍流状态的相似性。

Comments 10 pages, 12 figures

Journal ref Physical Review E 113, 065101 (2026)

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AI中文摘要

在[K. Yoshida, Phys. Rev. E, 106, 045106 (2022)]中提出了一个基于波数空间恒定通量状态的湍流系综模型。该系综模型的合理性依赖于一个猜想:几乎所有恒定通量状态都对应于湍流状态。为验证这一猜想,采用蒙特卡洛方法在二维湍流中数值搜索了有限时间间隔内波数空间具有恒定涡度通量的状态。检查了所得状态的性质,如能谱和与四阶矩相关的谱,并与直接数值模拟得到的湍流状态进行了比较。还讨论了所得状态对数值搜索中使用的时间间隔和初始条件的依赖性。

英文摘要

An ensemble model of turbulence based on states with constant flux in wavenumber space was proposed in [K. Yoshida, Phys. Rev. E, 106, 045106 (2022)]. The justification of this ensemble model relies on the conjecture that almost all states with constant flux correspond to turbulence states. To verify this conjecture, a numerical search for states with constant enstrophy flux in wavenumber space over finite time intervals in two-dimension turbulence is conducted using a Monte Carlo method. Properties of the obtained states, such as energy spectrum and spectra related to fourth-order moments, are examined and compared with those of turbulence states obtained from direct numerical simulations. The dependence of the obtained states on the time interval and the initial conditions used in the numerical search is also discussed.

2507.02224 2026-06-03 math.AP math-ph math.MP

Traveling Wave Solutions to a Large Class of Brenner-Navier-Stokes-Fourier Systems

一大类Brenner-Navier-Stokes-Fourier系统的行波解

Saehoon Eo, Namhyun Eun

AI总结 本文利用几何奇异摄动理论和隐函数定理,证明了在温度依赖输运系数和足够小激波振幅条件下,一维Brenner-Navier-Stokes-Fourier系统存在唯一单调行波解(粘性激波),并给出了定量估计。

Comments 18 pages

Journal ref Communications in Mathematical Sciences, 24(6), 1577-1593, 2026

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AI中文摘要

Brenner-Navier-Stokes-Fourier (BNSF) 系统由Howard Brenner引入,基于体积速度概念,旨在解决经典Navier-Stokes-Fourier系统的一些缺陷。我们考虑拉格朗日质量坐标下的一维BNSF系统,包含温度依赖的输运系数,从而得到更物理现实的框架。我们证明了对于任何正$C^2$耗散系数,只要激波振幅足够小,BNSF系统存在唯一单调行波解(或粘性激波)。我们像常系数情形[13]一样使用几何奇异摄动理论;然而,由于系数的任意非线性,我们采用隐函数定理,这赋予了我们的方法鲁棒性。这项工作受[12]启发,[12]证明了BNSF系统任何大解在行波解附近的收缩性质。因此,我们还推导了行波解的一些定量估计,这些估计在[12]中起基础作用。

英文摘要

The Brenner-Navier-Stokes-Fourier (BNSF) system, introduced by Howard Brenner, was developed to address some deficiencies in the classical Navier-Stokes-Fourier system, based on the concept of volume velocity. We consider the one-dimensional BNSF system in Lagrangian mass coordinates, incorporating temperature-dependent transport coefficients, which yields a more physically realistic framework. We establish the existence and uniqueness of monotone traveling wave solutions (or viscous shocks) to the BNSF system with any positive $C^2$ dissipation coefficients, provided that the shock amplitude is sufficiently small. We utilize geometric singular perturbation theory as in the constant coefficient case [13]; however, due to the arbitrary nonlinearities of the coefficients, we employ the implicit function theorem, which grants robustness to our approach. This work is motivated by [12], which proves a contraction property of any large solutions to the BNSF system around the traveling wave solutions. Thus, we also derive some quantitative estimates on the traveling wave solutions that play a fundamental role in [12].

2507.00135 2026-06-03 astro-ph.CO astro-ph.GA

DeepCHART: Mapping the 3D dark matter density field from Ly$α$ forest surveys using deep learning

DeepCHART: 利用深度学习从Lyα森林巡天绘制三维暗物质密度场

Soumak Maitra, Matteo Viel, Girish Kulkarni

AI总结 提出DeepCHART框架,基于3D变分自编码器与U-Net架构,从Lyα森林光谱中重建红移z=2.5处的三维暗物质密度场,实现高保真重建并适用于当前及未来巡天。

Comments 18 pages, 9 figures. Submitted to MNRAS. Comments are welcome

Journal ref Mon Not R Astron Soc (2026)

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AI中文摘要

我们提出了DeepCHART(用于宇宙学异质性和天体物理层析重建的深度学习),这是一个深度学习框架,旨在从Lyα森林光谱中重建红移z=2.5处的三维暗物质密度场。利用带有U-Net架构的3D变分自编码器,DeepCHART执行快速、无似然推断,准确捕捉嵌入在宇宙学流体动力学模拟中的非线性引力动力学和重子过程。当应用于结合Lyα森林吸收和同期星系位置的联合数据集时,重建质量进一步提高。对于当前的巡天,如Subaru/PFS、CLAMATO和LATIS,平均横向视线间距为d⊥=2.4h^{-1}cMpc,DeepCHART在密度范围0.4<ΔDM<15内实现了高保真重建,体素皮尔逊相关系数ρ≈0.77。这些重建使用的Lyα森林光谱信噪比低至2,仪器分辨率R=2500,符合Subaru/PFS的规格。对于由ELT/MOSAIC和WST/IFS等仪器实现的未来高密度巡天,d⊥≈1h^{-1}cMpc,相关系数提高到ρ≈0.90,动态范围更宽(0.25<ΔDM<40)。该框架可靠地恢复了暗物质密度概率分布函数和功率谱,仅在中尺度有轻微抑制。在宇宙网分类方面,DeepCHART成功识别了81%的voids、75%的sheets、63%的filaments和43%的nodes。我们提出DeepCHART作为一个强大且可扩展的场级宇宙学推断框架,易于推广到其他观测量,并为最大化即将到来的光谱巡天的科学回报提供了稳健、高效的手段。

英文摘要

We present DeepCHART (Deep learning for Cosmological Heterogeneity and Astrophysical Reconstruction via Tomography), a deep learning framework designed to reconstruct the three-dimensional dark matter density field at redshift $z=2.5$ from Ly$α$ forest spectra. Leveraging a 3D variational autoencoder with a U-Net architecture, DeepCHART performs fast, likelihood-free inference, accurately capturing the non-linear gravitational dynamics and baryonic processes embedded in cosmological hydrodynamical simulations. When applied to joint datasets combining Ly$α$ forest absorption and coeval galaxy positions, the reconstruction quality improves further. For current surveys, such as Subaru/PFS, CLAMATO, and LATIS, with an average transverse sightline spacing of $d_\perp=2.4h^{-1}$cMpc, DeepCHART achieves high-fidelity reconstructions over the density range $0.4<Δ_{\rm DM}<15$, with a voxel-wise Pearson correlation coefficient of $ρ\simeq 0.77$. These reconstructions are obtained using Ly$α$ forest spectra with signal-to-noise ratios as low as 2 and instrumental resolution $R=2500$, matching Subaru/PFS specifications. For future high-density surveys enabled by instruments such as ELT/MOSAIC and WST/IFS with $d_\perp\simeq 1h^{-1}\mathrm{cMpc}$, the correlation improves to $ρ\simeq 0.90$ across a wider dynamic range ($0.25<Δ_{\rm DM}<40$). The framework reliably recovers the dark matter density PDF as well as the power spectrum, with only mild suppression at intermediate scales. In terms of cosmic web classification, DeepCHART successfully identifies 81% of voids, 75% of sheets, 63% of filaments, and 43% of nodes. We propose DeepCHART as a powerful and scalable framework for field-level cosmological inference, readily generalisable to other observables, and offering a robust, efficient means of maximising the scientific return of upcoming spectroscopic surveys.

2411.07347 2026-06-03 cs.DM math.CO

An Efficient Genus Algorithm Based on Graph Rotations

基于图旋转的高效亏格算法

Alexander Metzger, Austin Ulrigg

AI总结 提出一种基于图旋转的算法,在O(n(4^m/n)^{n/t})步内确定简单有限连通图的可定向亏格,并输出最优嵌入的面。

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AI中文摘要

我们研究了确定简单有限连通图的最小亏格问题。我们提出了一种算法,对于任意具有n个顶点和m条边的图G,在O(n(4^m/n)^{n/t})步内确定G的可定向亏格,其中t是G的围长。该算法避免了其他许多亏格算法在处理桥放置时遇到的困难,这是一个众所周知的问题。该算法具有许多实用的特性:易于实现,输出最优嵌入的面,并迭代地缩小上下界。我们通过确定(3,12)笼形图(其亏格为17)的亏格来说明该算法;还考虑了其他图。

英文摘要

We study the problem of determining the minimal genus of a simple finite connected graph. We present an algorithm which, for an arbitrary graph $G$ with $n$ vertices and $m$ edges, determines the orientable genus of $G$ in $O(n(4^m/n)^{n/t})$ steps where $t$ is the girth of $G$. This algorithm avoids difficulties that many other genus algorithms have with handling bridge placements which is a well-known issue. The algorithm has a number of useful properties for practical use: it is simple to implement, it outputs the faces of an optimal embedding, and it iteratively narrows both upper and lower bounds. We illustrate the algorithm by determining the genus of the $(3,12)$ cage (which is 17); other graphs are also considered.

2108.08710 2026-06-03 math.AG

Derived isogenies and isogenies for abelian surfaces

阿贝尔曲面的导出同源与同源

Zhiyuan Li, Haitao Zou

AI总结 本文通过引入扭曲导出等价,利用Tate同源定理和推广的Shioda技巧,证明了在特征≠2,3的代数闭域上阿贝尔曲面的导出同源等价于主同源。

Comments 39 pages; The final version, to appear in Algebra & Number Theory

Journal ref Alg. Number Th. 20 (2026) 1185-1234

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AI中文摘要

本文研究了阿贝尔曲面的扭曲Fourier-Mukai伙伴。继Huybrechts的工作[doi:10.4171/CMH/465]之后,我们引入了阿贝尔曲面之间的扭曲导出等价。我们证明在特征≠2,3的代数闭域上,存在阿贝尔曲面的扭曲导出Torelli定理。在复数域上,导出同源对应于第二上同调群之间的有理Hodge等距,这类似于Huybrechts和Fu-Vial关于K3曲面的工作。他们的证明依赖于复数域上的全局Torelli定理,而在正特征下该定理缺失。为克服此问题,我们首先将Shioda关于整Hodge结构的一个技巧推广到有理Hodge结构、ℓ-adic Tate模和F-晶体。然后利用Tate同源定理,通过同源给出阿贝尔曲面之间扭曲导出等价的刻画。作为推论,我们证明两个阿贝尔曲面主同源当且仅当它们导出同源。

英文摘要

In this paper, we study the twisted Fourier-Mukai partners of abelian surfaces. Following the work of Huybrechts [doi:10.4171/CMH/465], we introduce the twisted derived equivalence between abelian surfaces. We show that there is a twisted derived Torelli theorem for abelian surfaces over algebraically closed fields with characteristic $\neq 2,3$. Over complex numbers, the derived isogenies correspond to rational Hodge isometries between the second cohomology groups, which is in analogy to the work of Huybrechts and Fu-Vial on K3 surfaces. Their proof relies on the global Torelli theorem over $\mathbb{C}$, which is missing in positive characteristics. To overcome this issue, we firstly extend a trick given by Shioda on integral Hodge structures, to rational Hodge structures, $\ell$-adic Tate modules and $F$-crystals. Then we make use of Tate's isogeny theorem to give a characterization of the twisted derived equivalences between abelian surfaces via isogenies. As a consequence, we show the two abelian surfaces are principally isogenous if and only if they are derived isogenous.

2503.11212 2026-06-03 cond-mat.quant-gas physics.atom-ph quant-ph

Josephson vortices and persistent current in a double-ring supersolid system

双环超固态系统中的约瑟夫森涡旋和持续电流

Malte Schubert, Koushik Mukherjee, Tilman Pfau, Stephanie Reimann

AI总结 研究径向耦合同心环状势阱中超冷偶极原子的超流-超固态相变,揭示旋转诱导的密度调制、持续电流以及中心涡旋和约瑟夫森涡旋的成核机制,并通过膨胀干涉图样区分不同涡旋构型。

Comments 7 figures, 12 pages

Journal ref Phys. Rev. Research 7, 033110 (2025)

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AI中文摘要

我们理论研究了由势垒创建的径向耦合同心环形陷阱中超冷偶极原子的性质。研究了无旋转基态相在超流-超固态相变过程中的行为,揭示了在没有旋转的情况下两个环之间的粒子不平衡以及外环中的优先密度调制。在超流侧接近相变时,施加旋转可以在任一个环中诱导密度调制,这取决于角动量和势垒强度。对于低角动量,这种旋转诱导的密度调制在外环形成,而对于高角动量和弱势垒,它出现在内环。旋转可以导致持续电流以及位于中心(中心涡旋)或环连接处(约瑟夫森涡旋)的涡旋成核。约瑟夫森涡旋也可以在内环中由旋转诱导的局域密度位点之间的连接处形成,这是我们的系统独有的行为。通过关闭陷阱并让系统膨胀,会出现不同的干涉图样,可以分析这些图样以识别和区分各种涡旋构型,从而可以在当前最先进的实验中观察到。

英文摘要

We theoretically investigate the properties of ultra-cold dipolar atoms in radially coupled, concentric annular traps created by a potential barrier. The non-rotating ground-state phases are investigated across the superfluid-supersolid phase transition, revealing a particle imbalance between the two rings and a preferential density modulation in the outer ring in the absence of rotation. Near the phase transition on the superfluid side, applying rotation can induce density modulations in either ring, depending on the angular momentum and barrier strength. For low angular momentum, such rotation-induced density modulation forms in the outer ring, while for high angular momentum and weak barriers, it emerges in the inner ring. Rotation can lead to persistent currents and the nucleation of a vortex residing either at the center (central vortex) or at the ring junction (Josephson vortex). Josephson vortices can also form at the junctions of the localized density sites induced by rotation in the inner ring, a behavior that is unique to our system. By switching off the trap and allowing the system to expand, distinct interference patterns emerge, which can be analyzed to identify and distinguish between various vortex configurations, and thus can be observed in current state-of-the-art experiments.

2506.19964 2026-06-03 cs.NE

Higher-Order Neuromorphic Ising Machines -- Autoencoders and Fowler-Nordheim Annealers are all you need for Scalability

高阶神经形态伊辛机——自编码器和福勒-诺德海姆退火器即可实现可扩展性

Faiek Ahsan, Saptarshi Maiti, Zihao Chen, Jakob Kaiser, Ankita Nandi, Madhuvanthi Srivatsav, Johannes Schemmel, Andreas G. Andreou, Jason Eshraghian, Chetan Singh Thakur, Shantanu Chakrabartty

AI总结 提出一种基于异步自编码器架构的高阶神经形态伊辛机,通过直接操作伊辛子句而非自旋来捕获高阶交互,结合福勒-诺德海姆量子隧穿退火动力学,在保持资源复杂度独立于交互阶数的同时,实现了优于二阶模型的解质量和可扩展性。

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AI中文摘要

我们报道了一种高阶神经形态伊辛机,与基于二次化的架构相比,它展现出优越的可扩展性,同时在解决方案中实现了最先进的质量和可靠性,并具有有竞争力的求解时间指标。该机器的核心是一种异步自编码器架构,通过直接操作伊辛子句而非伊辛自旋来捕获高阶交互,从而保持资源复杂度独立于交互阶数。通过基于福勒-诺德海姆量子力学隧穿退火动力学对由自旋定义的自编码器潜空间进行采样,确保了渐近收敛到伊辛基态。为了展示所提出的高阶神经形态伊辛机的优势,我们系统地解决了基准组合优化问题,如MAX-CUT和MAX-SAT,并将结果与使用相同退火过程的二阶伊辛机获得的结果进行了比较。我们的发现表明,在多次运行中,所提出的架构始终在更短的时间内提供更高质量的解决方案,相比二阶模型。此外,我们展示了基于互连矩阵稀疏性的技术,如图着色,可以有效地应用于高阶神经形态伊辛机,提高解决方案质量和求解时间。通过硬件协同设计可以进一步改善求解时间,如本文中使用现场可编程门阵列(FPGA)所展示的。本文呈现的结果进一步证明,自编码器和福勒-诺德海姆退火器足以实现任意阶神经形态伊辛机的可靠性和扩展性。

英文摘要

We report a higher-order neuromorphic Ising machine that exhibits superior scalability compared to architectures based on quadratization, while also achieving state-of-the-art quality and reliability in solutions with competitive time-to-solution metrics. At the core of the proposed machine is an asynchronous autoencoder architecture that captures higher-order interactions by directly manipulating Ising clauses instead of Ising spins, thereby maintaining resource complexity independent of interaction order. Asymptotic convergence to the Ising ground state is ensured by sampling the autoencoder latent space defined by the spins, based on the annealing dynamics of the Fowler-Nordheim quantum mechanical tunneling. To demonstrate the advantages of the proposed higher-order neuromorphic Ising machine, we systematically solved benchmark combinatorial optimization problems such as MAX-CUT and MAX-SAT, comparing the results to those obtained using a second-order Ising machine employing the same annealing process. Our findings indicate that the proposed architecture consistently provides higher quality solutions in shorter time frames compared to the second-order model across multiple runs. Additionally, we show that the techniques based on the sparsity of the interconnection matrix, such as graph coloring, can be effectively applied to higher-order neuromorphic Ising machines, enhancing the solution quality and the time-to-solution. The time-to-solution can be further improved through hardware co-design, as demonstrated in this paper using a field-programmable gate array (FPGA). The results presented in this paper provide further evidence that autoencoders and Fowler-Nordheim annealers are sufficient to achieve reliability and scaling of any-order neuromorphic Ising machines.

2309.10609 2026-06-03 econ.TH cs.GT math.CO

Game Connectivity and Adaptive Dynamics

博弈连通性与自适应动力学

Tom Johnston, Michael Savery, Alex Scott, Bassel Tarbush

AI总结 本文通过分析最佳响应图的连通性来研究博弈的典型结构,证明了在具有纯纳什均衡的“一般”博弈中,绝大多数是连通的,并基于此设计了几乎必然收敛到纯纳什均衡的简单自适应动力学。

Comments 45 pages

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AI中文摘要

我们通过博弈的最佳响应图的连通性性质来分析博弈的典型结构。我们的核心结果表明,在“一般”(无差异)且具有纯纳什均衡的博弈中,除了少数例外,绝大多数是\emph{连通的},这意味着每个非纯纳什均衡的行动配置都可以通过最佳响应路径到达每个纯纳什均衡。这对博弈中的动力学具有重要意义。特别是,我们证明了存在简单的、非耦合的自适应动力学,使得在除少数具有纯纳什均衡的一般博弈外,逐期博弈几乎必然收敛到纯纳什均衡(这与已知事实形成对比,即不存在这样的动力学能在\emph{每个}具有纯纳什均衡的一般博弈中几乎必然导致纯纳什均衡)。我们基于概率组合学的最新结果来刻画博弈连通性。

英文摘要

We analyse the typical structure of games in terms of the connectivity properties of their best-response graphs. Our central result shows that, among games that are `generic' (without indifferences) and that have a pure Nash equilibrium, all but a small fraction are \emph{connected}, meaning that every action profile that is not a pure Nash equilibrium can reach every pure Nash equilibrium via best-response paths. This has important implications for dynamics in games. In particular, we show that there are simple, uncoupled, adaptive dynamics for which period-by-period play converges almost surely to a pure Nash equilibrium in all but a small fraction of generic games that have one (which contrasts with the known fact that there is no such dynamic that leads almost surely to a pure Nash equilibrium in \emph{every} generic game that has one). We build on recent results in probabilistic combinatorics for our characterisation of game connectivity.

2501.01324 2026-06-03 stat.CO math.ST stat.AP stat.ME stat.ML stat.TH

Fast data inversion for high-dimensional Ornstein-Uhlenbeck processes from noisy measurements

基于噪声测量的高维Ornstein-Uhlenbeck过程的快速数据反演

Yizi Lin, Xubo Liu, Paul Segall, Mengyang Gu

AI总结 提出一种可扩展的潜在因子模型方法,利用正交因子载荷矩阵避免卡尔曼滤波中后验协方差矩阵求逆,并通过期望最大化算法导出闭式表达式降低计算复杂度,应用于高维时间序列噪声滤波、非可分离协方差结构估计及真实世界物理过程反演。

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AI中文摘要

在这项工作中,我们为高维动力系统开发了一种灵活潜在因子模型的可扩展方法。每个潜在因子过程有其自身的相关性和方差参数,正交因子载荷矩阵可以是固定的或估计的。我们利用正交因子载荷矩阵,避免了在卡尔曼滤波的每个时刻计算后验协方差矩阵的逆,并在期望最大化算法中推导出闭式表达式用于参数估计,从而在没有近似的情况下大幅降低了计算复杂度。我们的方法有多个应用,包括高维时间序列的噪声滤波、不同时间序列之间非可分离协方差结构的估计,以及从真实世界测量中估计潜在物理过程。广泛的模拟研究表明,与替代方法相比,我们的方法具有更高的准确性和可扩展性。此外,通过将我们的方法应用于大地测量数据以估计卡斯卡迪亚地区的慢滑事件,我们估计的滑移与独立测量的震颤事件地震数据更吻合。我们的方法带来的显著加速使得大规模噪声数据能够用于地质灾害量化及其他应用。

英文摘要

In this work, we develop a scalable approach for a flexible latent factor model for high-dimensional dynamical systems. Each latent factor process has its own correlation and variance parameters, and the orthogonal factor loading matrix can be either fixed or estimated. We utilize an orthogonal factor loading matrix that avoids computing the inversion of the posterior covariance matrix at each time of the Kalman filter, and derive closed-form expressions in an expectation-maximization algorithm for parameter estimation, which substantially reduces the computational complexity without approximation. Our approach has several applications, including noise filtering for high-dimensional time series, estimating nonseparable covariance structure between different time series, and estimating latent physical processes from real-world measurements. Extensive simulated studies illustrate higher accuracy and scalability of our approach compared to alternatives. Furthermore, by applying our method to geodetic measurements to estimate slow slip events from geodetic data in the Cascadia region, our estimated slip better agrees with independently measured seismic data of tremor events. The substantial acceleration from our method enables the use of massive noisy data for geological hazard quantification and other applications.

2506.15037 2026-06-03 math.PR math.OC

2BSDE with uncertain horizon and application to stochastic control in erratic environments

具有不确定时域的2BSDE及其在异常环境中的随机控制应用

Alberto Gennaro, Thibaut Mastrolia

AI总结 研究非马尔可夫二阶倒向随机微分方程在不确定终端时域下的存在唯一性和比较原理,并将其应用于两类非马尔可夫随机控制问题,提出异常随机控制的概念。

Comments v2: revised version

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AI中文摘要

我们研究了具有不确定终端时域的非马尔可夫二阶倒向随机微分方程的存在唯一性,并在驱动项Lipschitz连续的假设下建立了比较原理。终端时间是随机且外生的,可能不适应布朗滤波,导致2BSDE分解中出现奇异跳跃。我们还提供了这类新型2BSDE与马尔可夫框架下完全非线性PDE之间的联系。我们的理论结果应用于两种非马尔可夫随机控制问题:(1)当代理人通过控制扩散过程的漂移和波动率,以最大化在不确定终端时刻收到的收益的效用时;(2)当代理人面临来自外部源(称为自然)的波动率不确定性,并在最坏情况下优化漂移以应对模糊波动率时。我们将这类问题称为异常随机控制,反映了模型参数和终端时域的双重不确定性。

英文摘要

We investigate the existence and uniqueness of non-Markovian second-order backward stochastic differential equations with an uncertain terminal horizon and establish comparison principles under the assumption that the driver is Lipschitz continuous. The terminal time is both random and exogenous, and it may not be adapted to the Brownian filtration, leading to a singular jump in the 2BSDE decomposition. We also provide a connection between this new class of 2BSDE and a fully nonlinear PDE in a Markovian setting. Our theoretical results are applied to non-Markovian stochastic control problems in two settings: (1) when an agent seeks to maximize utility from a payoff received at an uncertain terminal time by controlling both the drift and volatility of a diffusion process; and (2) when the agent contends with volatility uncertainty stemming from an external source, referred to as Nature, and optimizes the drift in a worst-case scenario for the ambiguous volatility. We term this class of problems erratic stochastic control, reflecting the dual uncertainty in both model parameters and the timing of the terminal horizon.

2506.13220 2026-06-03 math.AG

Extended operational Chow group and Lefschetz (1,1)-theorem

扩展的操作Chow群与Lefschetz (1,1)-定理

Ananyo Dan, Inder Kaur

AI总结 本文通过引入扩展的操作Chow群,研究了从操作Chow群到Hodge (p,p)-类的Bloch-Gillet-Soulé(BGS)周类映射,证明了在有理奇点的正规曲面和孤立奇点情形下,该映射的满射性,从而推广了Lefschetz (1,1)-定理。

Comments 11 pages, Results generalised to the case of isolated singularities for all varieties, title has been changed to reflect this. Some inconsistencies have also been corrected

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AI中文摘要

设$X$是一个奇异的射影簇。对于每个$p>0$,$H^{2p}(X,\mathbb{Q})$配备了一个混合Hodge结构。$\mathrm{Gr}^W_{2p}H^{2p}(X,\mathbb{Q}) \cap H^{p,p} \mathrm{Gr}^W_{2p}H^{2p}(X,\mathbb{C})$中的元素称为Hodge (p,p)-类。本文的目的是研究从第$p$个操作Chow群$A^p(X)$到$(p,p)$-Hodge类空间的Bloch-Gillet-Soulé(BGS)周类映射。我们证明,如果$p=1$且$X\\)是一个至多具有有理奇点的正规曲面,那么BGS周类映射是满射的。这推广了Lefschetz $(1,1)$-定理到有理曲面奇点的情形。然而,BGS映射并不总是满射的。为此,我们引入了扩展的操作Chow群$A^p_{\mathrm{ext}}(X)$,它包含操作Chow群。我们证明BGS周类映射可以扩展到$A^p_{\mathrm{ext}}(X)$。此外,如果$p=1$且$X$至多具有孤立奇点(不一定是曲面),那么扩展的BGS映射是满射的。这进一步将Lefschetz $(1,1)$-定理推广到孤立奇点的情形。

英文摘要

Let $X$ be a singular, projective variety. For every $p>0$, $H^{2p}(X,\mathbb{Q})$ is equipped with a mixed Hodge structure. The elements of $\mathrm{Gr}^W_{2p}H^{2p}(X,\mathbb{Q}) \cap H^{p,p} \mathrm{Gr}^W_{2p}H^{2p}(X,\mathbb{C})$ will be called Hodge (p,p)-classes. The purpose of this article, is to study the Bloch-Gillet-Soulé (BGS) cycle class map from the $p$-th operational Chow group $A^p(X)$ to the space of $(p,p)$-Hodge classes. We show that if $p=1$ and $X$ is a normal surface with at worst rational singularities, then the BGS cycle class map is surjective. This extends the Lefschetz $(1,1)$-theorem to the setup of rational surface singularities. However, the BGS map is not always surjective. For this reason we introduce extended operational Chow group $A^p_{\mathrm{ext}}(X)$ which contains the operational Chow group. We show that the BGS cycle class map extends to $A^p_{\mathrm{ext}}(X)$. Moreover, if $p=1$ and $X$ has at worst isolated singularity (not necessarily a surface), then the extended BGS map is surjective. This further extends the Lefschetz $(1,1)$-theorem to the case of isolated singularities.

2412.07723 2026-06-03 math.NA cs.NA

Multilevel randomized quasi-Monte Carlo estimator for nested integration

嵌套积分的多水平随机拟蒙特卡罗估计

Arved Bartuska, André Gustavo Carlon, Luis Espath, Sebastian Krumscheid, Raúl Tempone

AI总结 针对嵌套积分问题,提出一种结合确定性和随机拟蒙特卡罗方法的多水平估计器,通过理论分析和数值实验证明其能显著降低偏差和方差,并在计算成本上优于传统方法。

Comments 45 pages, 10 figures

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AI中文摘要

嵌套积分问题出现在各种科学和工程应用中,包括贝叶斯实验设计、金融风险评估和不确定性量化。这些嵌套积分的形式为 $\int f\left(\int g(oldsymbol{y},oldsymbol{x})\mathrm{d}oldsymbol{x} ight)\mathrm{d}oldsymbol{y}$,其中 $f$ 是非线性的,这使得计算具有挑战性,尤其是在高维设置中。尽管传统蒙特卡罗方法广泛用于单积分,但在处理嵌套积分的复杂性时可能效率低下。本文介绍了一种新颖的多水平估计器,结合确定性和随机拟蒙特卡罗方法以高效处理嵌套积分问题。在此背景下,内层样本数和内层被积函数评估的离散化精度构成了水平。我们提供了估计器的全面理论分析,推导了误差界,表明与标准方法相比,偏差和方差显著降低。所提出的估计器在被积函数近似评估的情况下特别有效,因为它能适应不同分辨率水平而不牺牲精度。我们通过数值实验验证了方法的性能,重点估计实验的期望信息增益。当应用于实验中的高斯噪声时,截断方案确保了有限的误差界。结果表明,所提出的多水平随机拟蒙特卡罗估计器优于现有的蒙特卡罗和随机拟蒙特卡罗方法,显著降低了计算成本,并为处理跨领域的复杂嵌套积分问题提供了强大工具。

英文摘要

Nested integration problems arise in various scientific and engineering applications, including Bayesian experimental design, financial risk assessment, and uncertainty quantification. These nested integrals take the form $\int f\left(\int g(\boldsymbol{y},\boldsymbol{x})\mathrm{d}\boldsymbol{x}\right)\mathrm{d}\boldsymbol{y}$, for nonlinear $f$, making them computationally challenging, particularly in high-dimensional settings. Although widely used for single integrals, traditional Monte Carlo (MC) methods can be inefficient when encountering complexities of nested integration. This work introduces a novel multilevel estimator, combining deterministic and randomized quasi-MC (rQMC) methods to handle nested integration problems efficiently. In this context, the inner number of samples and the discretization accuracy of the inner integrand evaluation constitute the level. We provide a comprehensive theoretical analysis of the estimator, deriving error bounds demonstrating significant reductions in bias and variance compared with standard methods. The proposed estimator is particularly effective in scenarios where the integrand is evaluated approximately, as it adapts to different levels of resolution without compromising precision. We verify the performance of our method via numerical experiments, focusing on estimating the expected information gain of experiments. When applied to Gaussian noise in the experiment, a truncation scheme ensures finite error bounds. The results reveal that the proposed multilevel rQMC estimator outperforms existing MC and rQMC approaches, offering a substantial reduction in computational costs and offering a powerful tool for practitioners dealing with complex, nested integration problems across various domains.

2506.11518 2026-06-03 math.NA cs.NA

Transformed Diffusion-Wave fPINNs: Enhancing Computing Efficiency for PINNs Solving Time-Fractional Diffusion-Wave Equations

变换扩散波fPINNs:提高求解时间分数阶扩散波方程的PINNs计算效率

Jing Li, Zhengqi Zhang

AI总结 提出变换扩散波分数物理信息神经网络(tDWfPINNs),通过引入被积函数变换技术避免求积点处的一阶导数计算,显著降低分数阶导数评估的计算成本并保持精度,结合蒙特卡洛积分和高斯-雅可比求积方案,在时间分数阶偏微分方程上实现高效求解。

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AI中文摘要

我们提出了变换扩散波分数物理信息神经网络(tDWfPINNs),用于高效求解分数阶$\alpha\in(1,2)$的时间分数阶扩散波方程。这些方程的传统数值方法常常牺牲物理信息神经网络(PINNs)的无网格优势,或者在计算分数阶导数时带来高计算成本。所提出的方法通过引入被积函数变换技术,避免了求积点处的一阶导数计算,显著降低了与分数阶导数评估相关的计算成本,同时保持精度。我们进行了全面的比较分析,将这种被积函数变换与蒙特卡洛积分和高斯-雅可比求积方案相结合,应用于各种时间分数阶偏微分方程。结果表明,tDWfPINNs在不牺牲精度的情况下实现了卓越的计算效率。此外,我们将所提出的方法纳入自适应采样方法,如基于残差的自适应分布(RAD),用于求解阶数$\alpha\in(1,2)$的时间分数阶Burgers方程,该方程表现出复杂的解动态。实验表明,高斯-雅可比方法通常优于蒙特卡洛方法;然而,在选择求积点数量时需要仔细考虑。总体而言,所提出的tDWfPINNs在时间分数阶扩散波方程的数值求解方面取得了显著进展,为具有挑战性的分数阶模型提供了一种准确且可扩展的无网格替代方案。

英文摘要

We propose transformed Diffsuion-Wave fractional Physics-Informed Neural Networks (tDWfPINNs) for efficiently solving time-fractional diffusion-wave equations with fractional order $α\in(1,2)$. Conventional numerical methods for these equations often compromise the mesh-free advantage of Physics-Informed Neural Networks (PINNs) or impose high computational costs when computing fractional derivatives. The proposed method avoids first-order derivative calculations at quadrature points by introducing an integrand transformation technique, significantly reducing computational costs associated with fractional derivative evaluation while preserving accuracy. We conduct a comprehensive comparative analysis applying this integrand transformation in conjunction with both Monte Carlo integration and Gauss-Jacobi quadrature schemes across various time-fractional PDEs. Our results demonstrate that tDWfPINNs achieve superior computational efficiency without sacrificing accuracy. Furthermore, we incorporate the proposed approach into adaptive sampling approaches such as the residual-based adaptive distribution (RAD) for the time-fractional Burgers equation with order $α\in(1,2)$, which exhibits complex solution dynamics. The experiments show that the Gauss-Jacobi method typically outperforms the Monte Carlo approach; however, careful consideration is required when selecting the number of quadrature points. Overall, the proposed tDWfPINNs offer a significant advancement in the numerical solution of time-fractional diffusion-wave equations, providing an accurate and scalable mesh-free alternative for challenging fractional models.

2506.09468 2026-06-03 math.SP

The Levine--Weinberger and Friedlander--Filonov inequalities for some classes of elliptic operators

某些椭圆算子类的Levine--Weinberger和Friedlander--Filonov不等式

T. Schmatzler

AI总结 针对有界域上非齐次膜算子和散度型算子,证明Dirichlet与Neumann特征值之间的排序不等式,推广了Laplacian的Levine-Weinberger和Friedlander-Filonov结果。

Comments minor modifications

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AI中文摘要

我们考虑有界域上某些椭圆算子类的特征值问题,即非齐次膜算子 $ L = \tfrac{1}{ ρ} ( -Δ+ V ) $ 和散度型算子 $ L = -\operatorname{div} A \nabla $。对于这些算子,我们证明了Dirichlet与Neumann特征值之间的排序不等式,推广了Laplacian的Levine--Weinberger和Friedlander--Filonov结果。我们从他们的证明中汲取灵感,推导出确保不等式仍然成立的算子系数的充分条件。

英文摘要

We consider the eigenvalue problem for certain classes of elliptic operators, namely inhomogeneous membrane operators $ L = \tfrac{1}{ ρ} ( -Δ+ V ) $ and divergence form operators $ L = -\operatorname{div} A \nabla $, on bounded domains. For these operators, we prove ordering inequalities between the Dirichlet and the Neumann eigenvalues, generalizing results of Levine--Weinberger and Friedlander--Filonov for the Laplacian. We take inspiration from their proofs and derive sufficient conditions on the coefficients of the operator that ensure that the inequalities remain valid.

2505.20944 2026-06-03 cs.DL

International collaboration of Ukrainian scholars: Effects of Russia's full-scale invasion of Ukraine

乌克兰学者的国际合作:俄罗斯全面入侵乌克兰的影响

Myroslava Hladchenko

AI总结 本研究通过分析2022-2023年数据,探讨俄罗斯全面入侵对乌克兰学者国际合作的影响,发现大学在国际合作中获益多于国家科学院,但整体国际合作比例仍低于发达国家。

Journal ref Higher Education (2026)

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AI中文摘要

本研究探讨了俄罗斯全面入侵乌克兰对乌克兰学者国际合作的影响。首先,乌克兰学者在生命威胁、精神压力、炮击和停电的情况下仍坚持发表论文,值得尊敬。2022-2023年,大学从国际合作中获益多于国家科学院(NASU)。NASU的国际合著论文比例保持不变,而大学的比例有所增加。2023年,NASU发表的论文中有40.8%为国际合著,大学为32.2%。然而,这些数字仍远低于发达国家(60-70%)。国际合著论文的引用影响力对NASU而言统计上无变化,但对大学有所增加。两个时期中,NASU发表的国际合著论文最高比例出现在物理科学和工程领域。然而,这些论文的引用影响力在2022-2023年下降,几乎抹去了其先前相对于大学出版物的引用优势。在两个时期中,大学在生物医学和健康科学领域的国际合著论文引用影响力始终优于NASU。国际合作可以帮助乌克兰学者度过这段困难时期,而他们也可以为加强欧洲做出贡献。

英文摘要

This study explores the effects of Russia's full-scale invasion of Ukraine on the international collaboration of Ukrainian scholars. First and foremost, Ukrainian scholars deserve respect for continuing to publish despite life-threatening conditions, mental strain, shelling and blackouts. In 2022-2023, universities gained more from international collaboration than the NASU. The percentage of internationally co-authored articles remained unchanged for the NASU, while it increased for universities. In 2023, 40.8% of articles published by the NASU and 32,2% of articles published by universities were internationally co-authored. However, these figures are still much lower than in developed countries (60-70%). The citation impact of internationally co-authored articles remained statistically unchanged for the NASU but increased for universities. The highest share of internationally co-authored articles published by the NASU in both periods was in the physical sciences and engineering. However, the citation impact of these articles declined in 2022-2023, nearly erasing their previous citation advantage over university publications. Universities consistently outperformed the NASU in the citation impact of internationally co-authored articles in biomedical and health sciences across both periods. International collaboration can help Ukrainian scholars to go through this difficult time. In turn, they can contribute to the strengthening of Europe.

2505.12574 2026-06-03 cs.IR

Uncovering Competing Poisoning Attacks in Retrieval-Augmented Generation

揭示检索增强生成中的竞争性投毒攻击

Liuji Chen, Xiaofang Yang, Yuanzhuo Lu, Jinghao Zhang, Xin Sun, Qiang Liu, Shu Wu, Jing Dong, Liang Wang

AI总结 针对检索增强生成系统,研究多个攻击者同时投毒以争夺同一查询目标的问题,提出竞争有效性指标和PoisonArena框架。

Comments Accepted by KDD 2026. Project page: https://poison-arena.github.io/

Journal ref KDD 2026

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AI中文摘要

检索增强生成(RAG)系统改善了大语言模型(LLMs)的事实基础,但仍易受到检索投毒攻击,即对手向语料库注入被操纵的内容。先前的工作主要在简化的单一攻击者假设下评估这一威胁。然而,在实践中,高价值或高可见性的查询会吸引多个目标冲突的对手。受真实案例启发,我们引入了竞争攻击的设置,其中多个攻击者同时试图将相同或密切相关的查询引导至不同目标。我们形式化了这一威胁模型,并提出了竞争有效性,这是一个量化攻击者在竞争下优势的指标。大量实验表明,许多在单一攻击者设置下成功的策略在竞争下显著退化,揭示了性能反转并凸显了传统指标(如攻击成功率和F1)的局限性。此外,我们提出了PoisonArena,一个用于在现实的多对手条件下评估投毒攻击和防御的标准化框架和基准。

英文摘要

Retrieval-Augmented Generation (RAG) systems improve the factual grounding of large language models (LLMs) but remain vulnerable to retrieval poisoning, where adversaries seed the corpus with manipulated content. Prior work largely evaluates this threat under a simplified single-attacker assumption. In practice, however, high-value or high-visibility queries attract multiple adversaries with conflicting objectives. Motivated by real cases, we introduce the setting of competing attacks, in which multiple attackers simultaneously attempt to steer the same or closely related query toward different targets. We formalize this threat model and propose competitive effectiveness, a metric that quantifies an attacker's advantage under competition. Extensive experiments show that many strategies that succeed in the single-attacker regime degrade markedly under competition, revealing performance inversions and highlighting the limits of conventional metrics such as attack success rate and F1. Furthermore, we present PoisonArena, a standardized framework and benchmark for evaluating poisoning attacks and defenses under realistic, multi-adversary conditions.

2406.02957 2026-06-03 math.GT

A note on the involutive invariants of splices

关于拼接的对合不变量的注记

Kristen Hendricks, Matthew Stoffregen, Ian Zemke

AI总结 本文研究整数同调配边群中潜在2-挠元素(由纽结与其镜像拼接而成)的对合Floer同调,证明这些3流形具有局部平凡的对合Floer同调,并推广到相关拼接族,同时指出许多规范理论不变量在这些流形上消失。

Comments 15 pages. v2: Typo corrections and minor clarifications. This version to be published in Algebraic & Geometric Topology

Journal ref Algebr. Geom. Topol. 26 (2026) 1907-1921

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AI中文摘要

整数同调配边群中一个自然的潜在2-挠元素族由纽结与其镜像的拼接构成。我们证明这类3流形具有局部平凡的对合Floer同调。我们证明一些相关的拼接族也具有局部平凡的对合Floer同调。我们的论证表明,许多规范理论不变量在这些3流形上也消失。

英文摘要

A natural family of potentially 2-torsion elements in the integer homology cobordism group consists of splices of knots with their mirrors. We show that such 3-manifolds have locally trivial involutive Floer homology. We show some related families of splices also have locally trivial involutive Floer homology. Our arguments show that many gauge theoretic invariants also vanish on these 3-manifolds.

2405.19258 2026-06-03 math.AT

Polyhedral coproducts

多面体余积

Steven Amelotte, William Hornslien, Lewis Stanton

AI总结 通过将多面体积的对偶化,引入多面体余积作为单纯复形面偏序集上的同伦极限,并研究其基本性质,特别是给出了空间楔和与笛卡尔积之间的函子性插值以及对偶于Bahri等人悬架分裂的环路空间分解。

Comments 21 pages, expositional changes thanks to referee comments, version accepted by Algebraic & Geometric Topology

Journal ref Algebr. Geom. Topol. 26 (2026) 1781-1800

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AI中文摘要

将多面体积的构造对偶化,我们引入多面体余积的概念,作为单纯复形面偏序集上的某种同伦极限。我们开始研究多面体余积的基本性质,考察了各种熟悉例子和性质的对偶。特别地,我们证明多面体余积给出了空间楔和与笛卡尔积之间的函子性插值,这与多面体积给出的插值不同,并且我们建立了这些空间的一般环路空间分解,该分解对偶于Bahri、Bendersky、Cohen和Gitler的多面体积的悬架分裂。

英文摘要

Dualising the construction of a polyhedral product, we introduce the notion of a polyhedral coproduct as a certain homotopy limit over the face poset of a simplicial complex. We begin a study of the basic properties of polyhedral coproducts, surveying the Eckmann-Hilton duals of various familiar examples and properties of polyhedral products. In particular, we show that polyhedral coproducts give a functorial interpolation between the wedge and cartesian product of spaces which differs from the one given by polyhedral products, and we establish a general loop space decomposition for these spaces which is dual to the suspension splitting of a polyhedral product due to Bahri, Bendersky, Cohen and Gitler.

2305.04150 2026-06-03 math.KT math.AG math.AT

Motivic real topological Hochschild spectrum

动机实拓扑Hochschild谱

Doosung Park

AI总结 定义带对合的分离对数方案的实拓扑Hochschild同调,证明其(ℙⁿ,ℙⁿ⁻¹)-不变性,从而构造动机实拓扑Hochschild谱,并探讨其性质及动机实拓扑循环谱。

Comments 36 pages, accepted version, to appear in Algebraic & Geometric Topology

Journal ref Algebr. Geom. Topol. 26 (2026) 1867-1905

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AI中文摘要

我们定义了带对合的分离对数方案的实拓扑Hochschild同调。我们证明实拓扑Hochschild同调是$(\mathbb{P}^n,\mathbb{P}^{n-1})$-不变的,这导致了动机实拓扑Hochschild谱的定义,该谱存在于某个$\mathbb{Z}/2$-等变对数动机范畴中。我们探讨了可从对数动机同伦理论推导出的实拓扑Hochschild同调的性质。我们还定义了动机实拓扑循环谱。

英文摘要

We define real topological Hochschild homology of separated log schemes with involutions. We show that real topological Hochschild homology is $(\mathbb{P}^n,\mathbb{P}^{n-1})$-invariant, which leads to the definition of the motivic real topological Hochschild spectrum living in a certain $\mathbb{Z}/2$-equivariant logarithmic motivic category. We explore properties of real topological Hochschild homology that can be deduced from the logarithmic motivic homotopy theory. We also define the motivic real topological cyclic spectrum.

2505.16139 2026-06-03 cs.DC

On the Runtime of Local Mutual Exclusion for Anonymous Dynamic Networks

匿名动态网络中局部互斥的运行时间

Anya Chaturvedi, Joshua J. Daymude, Andréa W. Richa

AI总结 针对匿名动态网络中的局部互斥问题,本文证明了任何节点在发出锁请求后,期望在O(nΔ^3)个开放轮次内成功锁定自身及其持久邻居。

Comments 16 pages, 1 table

Journal ref 4th Symposium on Algorithmic Foundations of Dynamic Networks (SAND 2025), pp. 15:1-15:16

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AI中文摘要

互斥算法旨在隔离对同一共享资源的潜在并发访问。受可编程物质和群体协议(其中实体间的交互通常被假定为隔离的)的分布式计算研究启发,Daymude、Richa和Scheideler(SAND`22)引入了适用于任意动态网络的局部互斥问题变体:每个节点在发出锁请求时,必须获取自身及其所有持久邻居(即在锁请求期间保持连接的邻居)的排他锁。假设对抗性边动态、半同步或异步并发以及通过消息传递通信的匿名节点,他们的随机化算法实现了互斥(锁集不相交)和无锁死(以概率1最终成功)。然而,他们没有分析算法的运行时间。在本文中,我们证明任何节点在其锁请求后的期望开放轮次内,将成功锁定自身及其持久邻居,其中期望时间为O(nΔ^3),n是动态网络中的节点数,Δ是动态网络的最大度数,轮次归一化为“最慢”节点的执行时间,并且当某些持久邻居已被另一个节点锁定时,忽略“关闭”轮次(即仅考虑“开放”轮次)。

英文摘要

Algorithms for mutual exclusion aim to isolate potentially concurrent accesses to the same shared resources. Motivated by distributed computing research on programmable matter and population protocols where interactions among entities are often assumed to be isolated, Daymude, Richa, and Scheideler (SAND`22) introduced a variant of the local mutual exclusion problem that applies to arbitrary dynamic networks: each node, on issuing a lock request, must acquire exclusive locks on itself and all its persistent neighbors, i.e., the neighbors that remain connected to it over the duration of the lock request. Assuming adversarial edge dynamics, semi-synchronous or asynchronous concurrency, and anonymous nodes communicating via message passing, their randomized algorithm achieves mutual exclusion (non-intersecting lock sets) and lockout freedom (eventual success with probability 1). However, they did not analyze their algorithm's runtime. In this paper, we prove that any node will successfully lock itself and its persistent neighbors within O$(nΔ^3)$ open rounds of its lock request in expectation, where $n$ is the number of nodes in the dynamic network, $Δ$ is the maximum degree of the dynamic network, rounds are normalized to the execution time of the ``slowest'' node, and ``closed'' rounds when some persistent neighbors are already locked by another node are ignored (i.e., only ``open" rounds are considered).

2505.14496 2026-06-03 math.SG math.DG

Symplectic semi-characteristics

辛半特征

Hao Zhuang

AI总结 本文针对闭4n维辛流形定义辛半特征,利用具有非退化零点的向量场证明计数公式,并得到消失性质及定义与辛形式选择无关的结论。

Comments v2: accepted by Pacific Journal of Mathematics; v1: 23 pages. Comments are welcome

Journal ref Pacific J. Math. 343 (2026) 485-507

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AI中文摘要

我们研究闭4n维辛流形的辛半特征。首先,利用原始上同调的偶次部分,我们定义了辛半特征。其次,利用具有非退化零点的向量场,我们证明了辛半特征的计数公式。作为计数公式的推论,我们得到了一个消失性质以及辛半特征的定义与辛形式选择无关的事实。

英文摘要

We study the symplectic semi-characteristic of a closed 4n-dimensional symplectic manifold. First, using the even-degree part of the primitive cohomology, we define the symplectic semi-characteristic. Second, using a vector field with nondegenerate zero points, we prove a counting formula for the symplectic semicharacteristic. As corollaries of the counting formula, we obtain a vanishing property and the fact that the definition of the symplectic semi-characteristic is independent of the choices of symplectic forms.