arXivDaily arXiv每日学术速递 周一至周五更新
重置
全部学科分类 2079
2605.07416 2026-05-11 cond-mat.mes-hall

Effective Gilbert damping in the stochastic Landau-Lifshitz-Gilbert equation

Mexx. E. Y. Regout, Bertrand Dupé, Matthieu J. Verstraete

AI总结 本文研究了在引入温度和自旋波相互作用的情况下,一维自旋链中有效吉尔伯特阻尼参数的变化。通过求解随机兰道-李弗施茨-吉尔伯特方程,提取动力学关联函数并拟合动力学结构因子,得到了不同温度下的色散关系和散射率。研究发现,有效阻尼参数随温度和晶体动量变化,其行为可通过吉尔伯特浴和自旋波散射的相互作用进行解释。

详情
英文摘要

Quasi particle based (e.g. Boltzmann equation) studies of spin wave transport often assume that their scattering rates follow the simple form $η=αω$, with the Gilbert damping $α$ and frequency $ω$. In this work, we examine the effective damping $α_{eff,T}=η/ω$ observed in atomistic spin dynamics, when temperature and spin wave interactions are introduced for a 1D spin chain. We extract the dynamical correlation functions from spin trajectories propagated using the stochastic Landau-Lifshitz-Gilbert equation, and fit the dynamical structure factor, yielding the dispersion and scattering rates for a wide range of temperatures. The resulting effective damping can be very different from the initially constant Gilbert value. It exhibits a temperature and crystal momentum scaling which we explain based on interactions with the Gilbert bath and spin wave scattering by changes in local magnetic order.

2605.07411 2026-05-11 math.PR math.FA

A note on the equivalence of super-Poincaré inequality

Xin Chen, Qiuchen Yang

AI总结 本文研究了超Poincaré不等式与若干对数Sobolev型不等式(包括弱对数Sobolev不等式和超对数Sobolev不等式)之间的等价性,并建立了相关速率函数之间的显式关系。这一结果深化了对不同函数不等式之间联系的理解,为概率论与泛函分析中的相关研究提供了理论支持。

详情
英文摘要

In this paper we will study the equivalence between super-Poincaré inequality and some log-Sobolev type inequalities, including weak log-Sobolev inequality and super log-Sobolev inequality. The explicit relations between associated rate functions will also be established.

2605.07410 2026-05-11 math-ph cond-mat.stat-mech math.MP math.SP

Volume-Independent Spectral Stability of Energy-Truncated Effective Hamiltonians in Quantum Spin Systems

Ayumi Ukai

AI总结 本文研究了有限范围量子自旋系统中能量截断有效哈密顿量的谱稳定性问题,提出了一种适用于无限晶格的体积统一的有效哈密顿量定理。通过构造有限目标区域的能量截断哈密顿量,并证明其低能谱子空间向原哈密顿量高能谱子空间泄漏的体积统一谱重叠界,从而在有限体积中保证低能本征值的稳定性,在无限体积中则在GNS表示下建立了相应的谱重叠估计。该结果推广并加强了已有有效哈密顿量机制,适用于热力学极限下的有界有限范围相互作用系统。

Comments 25 pages, no figures

详情
英文摘要

We prove a volume-uniform effective-Hamiltonian theorem for bounded finite-range quantum spin systems on possibly infinite lattices. For any finite target region, we construct an energy-truncated Hamiltonian and prove a volume-uniform spectral-overlap bound controlling the leakage of its low-energy spectral subspace into the high-energy spectral subspace of the original Hamiltonian. The bound may contain non-exponential spectral-window terms, but its cutoff-dependent remainder decays exponentially in the cutoff. In finite volume, this yields stability of low-lying eigenvalues, with eigenvalue errors controlled by the exponentially small cutoff-dependent remainder. In infinite volume, we prove the corresponding spectral-overlap estimate in the GNS representation of an infinite-volume ground state. Thus, for bounded finite-range interactions, we extend and strengthen the effective-Hamiltonian mechanism of Arad, Kuwahara, and Landau by replacing the finite-volume operator-norm formulation with a volume-uniform spectral-overlap formulation applicable in the thermodynamic limit.

2605.07408 2026-05-11 math.NA cs.NA

Newton's method for optimal transport problem on graphs

Qujiangxue Chen, Jianbo Cui, Luca Dieci, Haomin Zhou

AI总结 本文研究了在连通图上基于Benamou-Brenier框架的动力学最优传输问题,将密度分配给顶点、速度分配给边。针对直接使用牛顿法可能遇到的循环导致变量不唯一和密度可能为负的问题,提出了一种基于生成树规范的有限差分型牛顿法,消除了冗余变量,得到稀疏且良置的线性系统,并通过迎风离散保证密度的正性。该方法在格点图、随机图、逆最优传输问题及社交网络分析中均表现出良好的适用性。

详情
英文摘要

In this paper, we study dynamical optimal transport on a connected graph from the perspective of the Benamou-Brenier formulation, where densities are assigned to vertices and velocities to edges. However, directly using Newton's method on the resulting nonlinear systems encounters two potential difficulties: (i) if the graph contains cycles, edge variables are not unique, and (ii) there is no guarantee that the density variables remain positive. To address these challenges, we introduce a finite-difference-type Newton method that eliminates cycle-induced redundancies through a spanning-tree gauge, resulting in a reduced set of independent variables and a well-posed, sparse linear system. For the lattice graph arising from the continuous optimal transport problem, density positivity can also be guaranteed by using an upwind discretization subject to a CFL-type condition. We further demonstrate the versatility of the proposed scheme by applying it to a range of problems, including optimal transport on lattices and random graphs, inverse optimal transport problems, and social network analysis.

2605.07406 2026-05-11 physics.ins-det

Design and Characterization of Racetrack 3D-Trench Silicon Sensor Based on 8-Inch Process with Excellent Time Resolution

Huimin Ji, Manwen Liu, Kuo Ma, Chuan Liao, Yanwen Liu, Zheng Li, Zhihua Li, Jun Luo

AI总结 在高亮度对撞机等极端环境下,传统平面硅传感器因辐射损伤导致性能下降,难以满足高精度轨迹测量和高速时间分辨的需求。本文提出了一种新型的跑道形3D沟槽硅传感器,通过环绕长中央收集电极的连续跑道电极结构,有效消除电场不均匀性,提升电荷收集效率和时间分辨能力。该传感器基于8英寸平台首次实现了23微米浅刻蚀工艺,具备大规模制造潜力,并在漏电流、击穿电压、时间响应等方面表现出优异性能,为高辐射和高事例率条件下的便携式辐射探测和下一代4D轨迹测量提供了有竞争力的解决方案。

详情
英文摘要

In the extreme environments of high-luminosity colliders, traditional planar silicon sensors suffer severe radiation-induced performance degradation and fail to satisfy the stringent demands of high-precision tracking and high-speed timing in particle physics. 3D silicon sensors enhance radiation hardness by shortening charge collection distance, yet conventional designs with columnar or square-cell trench electrodes exhibit non-uniform electric fields, including saddle points and low-field regions, which degrade charge collection efficiency and timing resolution. This work presents a novel racetrack 3D-trench silicon sensor with continuous racetrack electrodes surrounding a long central collection electrode, aiming to eliminate electric field inhomogeneities. For the first time, a 23 $μ$m shallow-etched device was fabricated on an 8-inch platform, which provides a promising basis for its subsequent mass production and engineering applications. The device performance was systematically evaluated through theoretical analysis, 3D TCAD simulations, and characterization using semiconductor parameter analyzers and transient current technique (TCT) measurements. The sensor achieves leakage current below 0.2 nA, breakdown voltage above 110 V, full depletion voltage as low as a few volts, capacitance as low as 650 fF, collected charge of 4 fC, time response of about 640 ps, and time resolution of 50 ps. This large-scale manufacturable, shallow-etched racetrack 3D-trench silicon sensor provides a competitive device solution for portable radiation detection and next-generation 4D tracking under high-radiation and high-event-rate conditions.

2605.07405 2026-05-11 quant-ph

Commutativity from a single Bargmann invariant equality

Rafael Wagner, Ernesto F. Galvão

AI总结 本文研究了量子态之间交换性的判断条件,提出了一个通用的充要条件:两个量子态 $ρ_1$ 和 $ρ_2$ 交换当且仅当 $\mathrm{tr}(ρ_1^2ρ_2^2) = \mathrm{tr}(ρ_1ρ_2ρ_1ρ_2)$。对于二能级系统,该条件可简化为关于纯度和态重叠的多项式等式,这些可测的多变量迹(即Bargmann不变量)使得无需完整态重构即可检测交换性。该成果可应用于研究POVM可模拟性及部分光子可区分性等问题。

Comments 5+4 pages, no figures. Comments are welcome!

详情
英文摘要

Noncommutativity of states and observables is a fundamental signature of quantum theory, and a minimal requirement for nonclassicality. We provide a universal necessary and sufficient condition for pairwise commutativity of quantum states $ρ_1$ and $ρ_2$: they commute if and only if $\mathrm{tr}(ρ_1^2ρ_2^2) = \mathrm{tr}(ρ_1 ρ_2 ρ_1 ρ_2)$. For qubits the identity simplifies to an equality between polynomials of purities and of the two-state overlap $\mathrm{tr}(ρ_1ρ_2)$. These multivariate traces (known as Bargmann invariants) are directly measurable, allowing commutativity tests that bypass full state tomography. We point out possible applications to the analysis of POVM simulability and partial photonic distinguishability.

2605.07404 2026-05-11 math.ST econ.EM stat.TH

Self-normalized tests for multistep conditional predictive ability

Qitong Chen, Shuwen Lai

AI总结 本文提出了一种用于多步条件预测能力比较的自归一化检验方法。通过利用变换后损失差值样本均值的累积和(CUSUM)过程的功能量进行归一化,该方法避免了对长期协方差矩阵的直接估计,从而省去了传统方法中所需的带宽、核函数和滞后截断等人为设定。研究建立了该检验统计量的渐近理论,推导了其在原假设下的极限分布,并证明了检验的一致性。仿真实验表明,该方法有效缓解了传统异方差与自相关一致(HAC)方法在小样本下的显著性扭曲问题,同时保持了对条件可预测性备择假设的强大检验能力。

详情
英文摘要

This paper proposes self-normalized tests for multistep conditional predictive ability in forecast comparison. By normalizing the sample mean of the transformed loss differential using functionals of its cumulative sum (CUSUM) process, specifically an adjusted-range normalizer for scalars and a matrix normalizer for vectors, our approach avoids direct estimation of the long-run covariance matrix. Consequently, it eliminates the need for the ad hoc bandwidth, kernel, and lag-truncation choices required by traditional methods. We establish the asymptotic theory for these statistics, deriving pivotal null limiting distributions and proving test consistency. Monte Carlo simulations show that the proposed tests effectively mitigate the finite-sample size distortions associated with traditional heteroskedasticity and autocorrelation consistent (HAC) methods, while retaining strong empirical power against conditional predictability alternatives.

2605.07403 2026-05-11 cs.SE

Boosting Automatic Java-to-Cangjie Translation with Multi-Stage LLM Training and Error Repair

Xinyue Liang, Jingxuan Zhang, Lin Li, Jun Zhang, Junhao Chen

AI总结 随着新兴编程语言生态的快速发展,将代码翻译为资源较少的语言需求日益增长。针对新出现的编程语言Cangjie,本文提出了一种多阶段大语言模型训练框架,结合迭代错误修复技术,以提升从Java到Cangjie的自动代码翻译质量。该方法通过整合编译器反馈和错误修复案例检索,逐步增强模型对Cangjie语法和语义的理解,实验表明在有限平行数据下,该方法在功能等价性上较现有方法提升了6.06%。

详情
英文摘要

With the rapid evolution of emerging programming language ecosystems, the demand for code translation to low-resource languages continues to grow. As Cangjie emerges as a new programming language, its ecosystem and development toolchains are rapidly expanding. Automated translation from popular programming languages to Cangjie is therefore valuable for practical development. However, constrained by both insufficient Cangjie knowledge and scarce parallel code corpora, general Large Language Models (LLMs) are prone to syntactic errors and semantic as well as structural misalignment in code translation. Existing approaches typically rely on fine-tuning with large-scale parallel data, but they cannot reliably improve compilability or semantic consistency for low-resource Cangjie languages. To tackle these challenges, we propose a multi-stage training framework of LLMs that employs the iterative error repair technique to translate Java code into Cangjie code. This training framework performs training on LLMs, gradually integrating knowledge and achieving semantic alignment as well as structure awareness. During the code translation, we also combine the compiler feedback and error repair case retrieval to repair the incorrect Cangjie code. We construct syntactic knowledge and monolingual instruction datasets to train the LLM. In addition, we also build a Cangjie error repair repository to support error repair in our approach. Experimental results show that, with limited parallel data, our approach improves functional equivalence by 6.06\% compared to the state-of-the-art approaches. Meanwhile, ablation studies confirm that each training stage positively contributes to the final performance.

2605.07401 2026-05-11 eess.SY cs.SY

Learning myopic mixed-integer nonlinear model predictive control from expert demonstrations

Christopher Anthony Orrico, W. P. M. H. Heemels, Dinesh Krishnamoorthy

AI总结 本文研究了如何通过专家示范学习来解决混合整数非线性模型预测控制(MINMPC)的实时计算难题。提出了一种基于价值函数近似的短视MINMPC框架,通过缩短预测时域并结合离线学习的价值函数,显著降低了在线计算负担。该方法在离线阶段放松整数约束以学习价值函数,在在线阶段恢复整数约束以确保可行性,最终在多个实际系统中实现了高效且接近专家策略的闭环控制性能。

Comments Accepted proceedings 23rd IFAC World Congress, Busan Korea

详情
英文摘要

Applying nonlinear model predictive control (NMPC) to systems with hybrid dynamics or discrete actions typically yields mixed-integer nonlinear programs (MINLPs), whose real-time solution remains a major challenge and limits the applicability of mixed-integer NMPC (MINMPC). This paper proposes a myopic MINMPC framework that incorporates value-function approximation to substantially reduce the online computational burden. Using Bellman's principle of optimality, we shorten the prediction horizon and append a value function learned offline from expert state-action demonstrations via inverse optimization with optimality residual minimization. A central feature is the dual treatment of discrete decisions, whereby integer constraints are relaxed during offline learning to enable KKT-residual-based value function synthesis, while the online controller enforces the true integer constraints to ensure feasibility. The learned value function induces a policy that is approximately policy-consistent with the expert demonstrations. The resulting controller achieves high closed-loop performance with a significantly shorter horizon, enabling real-time MINMPC. The effectiveness of the approach is demonstrated on the Lotka-Volterra fishing problem and a satellite attitude control system with discrete actuators.

2605.07400 2026-05-11 cs.CR

From Conceptual Scaffold to Prototype: A Standardized Zonal Architecture for Wi-Fi Security Training

Vyron Kampourakis, Efstratios Chatzoglou, Vasileios Gkioulos, Sokratis Katsikas

AI总结 本文针对Wi-Fi安全培训中缺乏专用实验环境的问题,提出了一种面向IEEE 802.11安全场景的标准化区域化架构,并开发了开源原型系统。该架构基于现有的网络安全实验平台设计原则,划分为核心基础设施、学习管理、监控管理及访问控制等区域,支持模块化、可扩展性与未来功能扩展。原型系统实现了场景生成、存储、检索与实例化流程,为Wi-Fi安全实验提供了初步的实践基础。

详情
英文摘要

Wi-Fi is the dominant wireless access technology, but its widespread use also exposes systems to threats such as rogue access points, deauthentication attacks, and other IEEE 802.11-specific vulnerabilities. Although Cyber Ranges (CRs) have become valuable platforms for cybersecurity training and experimentation, existing wireless-oriented solutions mainly target heterogeneous IoT or mobile-network settings, with Wi-Fi typically treated as one among many. As a result, dedicated CR environments for Wi-Fi-specific security experimentation remain limited. This gap is particularly relevant because wireless attacks often require protocol-aware experimentation that is difficult to reproduce in conventional training environments. This paper introduces a conceptual architecture for a Wi-Fi-focused CR tailored to IEEE 802.11 security scenarios and an open-source prototype. The proposed design is grounded in established CR design principles and organized around core infrastructure, learning management and support, monitoring, management, and access-control zones. Structuring the platform into these distinct zones, the architecture supports modularity, scalability, and future extensibility. Part of the design is realized in a prototype publicly available in a GitHub repository that implements the scenario generation, storage, retrieval, and instantiation workflow, offering an initial practical foundation for the proposed architecture. Overall, the paper provides a structured foundation for the future implementation of Wi-Fi-specialized CR platforms for targeted experimentation.

2605.07392 2026-05-11 astro-ph.EP astro-ph.GA

Mass Production of 2023 KMTNet Microlensing Planets. III: Three Planets from the Subprime Field

Hongyu Li, Zhixing Li, Weicheng Zang, Yoon-Hyun Ryu, Andrzej Udalski, Takahiro Sumi, Hongjing Yang, Jiyuan Zhang, Shude Mao, Michael Albrow, Sun-Ju Chung, Andrew Gould, Cheongho Han, Kyu-Ha Hwang, Youn Kil Jung, In-Gu Shin, Yossi Shvartzvald, Jennifer Yee, Sang-Mok Cha, Dong-Jin Kim, Seung-Lee Kim, Chung-Uk Lee, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard Pogge, Przemek Mróz, Michał Szymański, Jan Skowron, Radoslaw Poleski, Igor Soszyński, Pawel Pietrukowicz, Szymon Kozłowski, Krzysztof Rybicki, Patryk Iwanek, Krzysztof Ulaczyk, Marcin Wrona, Mariusz Gromadzki, Mateusz J. Mróz, Fumio Abe, David Bennett, Aparna Bhattacharya, Ian Bond, Ryusei Hamada, Yuki Hirao, Stela Silva, Shota Miyazaki, Yasushi Muraki, Kansuke Nunota, Greg Olmschenk, Clément Ranc, Nicholas Rattenbury, Yuki Satoh, Daisuke Suzuki, Takuto Tamaoki, Sean Terry, Paul Tristram, Aikaterini Vandorou, Hibiki Yama

AI总结 本文分析了KMTNet望远镜2023年在次优区域发现的六起微引力透镜天体物理事件,确认其中三起为行星事件,并估算其质量比分别为$\log q \sim -1.9$、$-2.0$和$-2.6$。其余三起事件存在双镜单源与单镜双源模型的典型退化问题,其中两起还存在恒星双星的可行解。研究还指出,确认的行星伴侣可能为围绕M型或K型矮星运行的超级木星,或围绕晚型M矮星运行的土星质量行星。目前2023年KMTNet样本已确认25个明确的行星事件,其质量比分布与2016至2019年的样本一致。

Comments Submitted to PASP

详情
英文摘要

To complete the analysis of the 2023 KMTNet subprime-field microlensing planetary events identified by its AlertFinder system, we present the analysis of six events, KMT-2023-BLG-(1810, 0084, 1118, 0584, 1697, 2218). We find that the first three events are securely confirmed as planetary, with inferred mass ratios of $\log q \sim -1.9$, $-2.0$, and $-2.6$, respectively. The remaining three events exhibit the well-known degeneracy between binary-lens/single-source (2L1S) and single-lens/binary-source (1L2S) models, and two of these also admit viable stellar binary solutions. A Bayesian analysis indicates that the companions in the confirmed planetary events are likely either super-Jupiters orbiting beyond the snow line of M- or K-dwarf hosts or, for two degenerate solutions of KMT-2023-BLG-1118, Saturn-mass planets orbiting late-type M dwarfs. To date, the 2023 KMTNet sample contains 25 unambiguous planetary events, and its mass-ratio distribution is consistent with that of the KMTNet planetary sample from 2016--2019.

2605.07391 2026-05-11 cs.DC

MERBIT: A GPU-Based SpMV Method for Iterative Workloads

Qi Zhang, Zhengan Yao, Zhenglu Jiang, Zan-Bo Zhang

AI总结 本文提出了一种基于GPU的SpMV(稀疏矩阵-向量乘法)方法MERBIT,旨在加速迭代型工作负载中的稀疏矩阵运算,尤其适用于具有不规则结构的图数据。MERBIT结合了全局的合并路径划分和局部的紧凑位字段编码,以提升负载均衡和内存访问效率,并引入了三种优化策略进一步提高性能。实验表明,MERBIT在50个大型不规则数据集上优于多个现有方法,分别在单精度和双精度下比cuSPARSE COO平均快1.27倍和1.25倍。

详情
英文摘要

Sparse Matrix-Vector Multiplication (SpMV) is the cornerstone in many iterative workloads, including large-scale graph analytics and sparse iterative solvers. Accelerating SpMV on real-world graphs remains challenging due to highly irregular sparsity patterns. In this paper, we propose MERBIT, a GPU SpMV method designed for repeated SpMV on irregular, graph-like sparse matrices, with PageRank as a representative motivating workload. MERBIT combines two key ideas from existing GPU SpMV methods. At the global level, it uses merge-path partitioning to balance work over nonzeros and row boundaries. At the local level, it encodes each merge-path segment using a compact bit-field descriptor. MERBIT improves workload balance and promotes coalesced memory access for both matrix loading and output writes; moreover, three optimization strategies are incorporated to further enhance performance. Experiments on 50 large irregular datasets demonstrate that MERBIT outperforms competitive baselines, including cuSPARSE, Ginkgo, and academic approaches, achieving average speedups of 1.27 and 1.25 over cuSPARSE COO in single and double precision, respectively.

2605.07387 2026-05-11 cs.GT cs.CR

Game-Theoretic Analysis of Transaction Selection in DAG-Based Distributed Ledgers

Sebastian Müller, Alexandre Reiffers-Masson

AI总结 本文研究了基于DAG的分布式账本中交易选择机制的设计问题,重点分析了两种常见的费用分配机制——随机费用分配(RFA)和协作费用共享(CFS)对验证者行为和系统性能的影响。通过博弈论框架,作者推导了两种机制下的对称纳什均衡,并提出了一种优化方法计算这些均衡。实验表明,CFS机制在吞吐量和奖励分配方面优于RFA,尤其在费用分布不均的情况下表现更优,为构建高效、公平的DAG账本系统提供了理论支持和设计参考。

详情
Journal ref
2025 IEEE International Conference on Blockchain and Cryptocurrency (ICBC)
英文摘要

Transaction selection in parallel or DAG-based distributed ledger technologies (DLTs) is a crucial challenge that directly impacts throughput, fairness, and validator incentives. In these systems, validators independently choose transactions to include in their blocks, often relying on naive heuristics like uniform or proportional selection. This can lead to inefficient outcomes when validators prioritize their own rewards without considering collective impacts. We analyze two fee allocation mechanisms used in practice: Random Fee Allocation (RFA), where transaction fees are randomly assigned to one validator, and Collaborative Fee Sharing (CFS), where fees are distributed equally among all validators. Using a single-shot game-theoretic framework, we derive symmetric Nash equilibria (NE) for selecting transactions for both mechanisms and propose an optimization-based method to compute these equilibria. Numerical simulations demonstrate that the NE of CFS consistently achieves higher throughput and rewards compared to the NE of RFA, particularly under skewed fee distributions. Additionally, we compare these equilibrium strategies to naive benchmarks (uniform and proportional selection), showing that the proportional strategy outperforms the NE of RSA in many situations. These findings may provide actionable insights into the design of transaction selection and incentive mechanisms, enabling more robust and high-performance DAG-based DLTs.

2605.07383 2026-05-11 cs.CR stat.AP

Combating Organized Platform Abuse: Amplifying Weak Risk Signals with Structural Information

Meng He, Jia Long Loh

AI总结 本文针对在线平台面临的有组织滥用行为,提出了一种基于经济约束的欺诈三难困境理论,揭示了有组织欺诈行为的结构性不变特征——集中式提现,并利用简单的统计方法将低精度的弱信号放大为高精度的强决策。该方法无需标注数据、参数极少、可解释性强,且具备“开手”特性,即使攻击者完全知情也难以规避。实验验证表明,该方法在推广滥用和信用卡欺诈两种真实场景中均取得了极高的检测精度和召回率。

Comments 11 pages, 6 figures, 8 tables

详情
英文摘要

Large-scale online service platforms face severe challenges from organized platform abuse: multiple forms such as credit card fraud and promotion abuse continually emerge, characterized by large numbers of involved accounts, rapid outbreaks, and constantly shifting tactics. Existing mainstream approaches, whether heuristic rules limited in precision, supervised learning with insufficient generalization, or graph models that are engineering-heavy and dependent on seed users, have failed to address such threats effectively. This paper returns to first principles and, starting from the economic constraints of fraudulent behavior, proposes the Fraudster's Trilemma: organized attackers cannot simultaneously achieve scale, low cost, and dispersed cash-out. Building on this theory, we derive a robust structural invariant in organized fraud, namely centralized cash-out, and use a simple statistical method to turn low-precision individual weak signals into high-precision strong decisions. The method requires no labels, is nearly parameter-free, white-box interpretable, has linear complexity O(|E|), avoids cold-start issues, and its detection logic possesses the "open-hand" property: attackers cannot evade it even when fully informed. We validate the approach on two real fraud incidents in backtests. In the promotion abuse case, a single near-zero-cost weak signal (global Precision of only 16%) after structural amplification achieves Precision above 91% and Recall exceeding 99% (z=10.0); at a higher threshold (z=40.0), Precision reaches 93.7%. In the credit card fraud case, an infrastructure-layer weak signal (device spoofing) successfully detects payment-layer attacks without any business-logic linkage, revealing the framework's natural MO-agnostic property: it relies more on the structural invariant than on signal semantics.

2605.07382 2026-05-11 cond-mat.mtrl-sci

Revisiting Ferroelectricity Beyond Polar Space Groups

Yudi Yang, Changming Ke, Shi Liu

AI总结 本文重新审视铁电性的本质,指出传统基于极性空间群的理论已不足以解释近年来发现的新型铁电现象。作者基于Berry相位理论,提出极化是一个多值晶格量,非极性晶体也可能具有非零极化,从而统一解释了分数量子铁电性和离子导体铁电性等新现象。研究还揭示了这些材料在非传统极化态调控、电荷界面和畴壁控制方面的潜在应用价值。

详情
英文摘要

Ferroelectricity, a hallmark of spontaneous inversion-symmetry breaking, has been a central concept in condensed matter physics and functional materials research, yet recent discoveries are revealing that switchable polarization can emerge in forms far richer than allowed by the conventional symmetry-based paradigm. Fractional quantum ferroelectricity and ionic-conductor ferroelectricity challenge the long-standing association of ferroelectricity exclusively with polar space groups. In this Review, we reconcile these emerging phenomena within the Berry-phase modern theory of polarization. We emphasize that polarization in insulating periodic crystals is not a single-valued vector, but a multivalued lattice quantity defined modulo a polarization quantum. Consequently, nonpolar crystals may possess nonzero formal polarization, and adiabatic paths connecting symmetry-equivalent structures can produce quantized changes in polarization without violating symmetry principles. The symmetry of this multivalued formal polarization is governed by a generalized Neumann principle. We further show that the large polarization changes induced by long-range ion migration in both fractional quantum ferroelectrics and ionic-conductor ferroelectrics can be naturally understood through the topological definition of oxidation state, which links ionic transport to quantized charge transfer and polarization change. We discuss the physical accessibility of these unconventional polarization states, highlighting the roles of switching pathways, boundary conditions, and domain-wall dynamics, particularly in systems such as $α$-In$_2$Se$_3$. Finally, we suggest that the most promising functionality of these materials may lie not in conventional bulk ferroelectric switching, but in the creation and control of charged interfaces and domain walls arising from discontinuities in formal polarization.

2605.07380 2026-05-11 math.CO math-ph math.MP

Counting LEGO configurations

Anthony J Guttmann, Rasmus M Nilsson

AI总结 本文研究了乐高积木结构的计数问题,主要关注由平行 $w \times 1$ 积木组成的二维和三维结构。通过分析不同组合方式,提出了用于计算配置数的算法,并推测其增长形式为指数函数除以多项式因子。研究还证明了在固定积木数量时,不同宽度的配置数序列是关于宽度的多项式,并给出了具体表达式。

Comments 23 pages, 12 figures

详情
英文摘要

We discuss the problem of counting certain LEGO structures, primarily those comprising parallel $w \times 1$ tiles. These can be combined, as a single LEGO structure, by interlocking the tiles. %Alternatively, if the interlocking condition is relaxed, so that tiles can also be placed end-to-end, a greater number of possible configurations results. We also study the historically earlier problem of counting the number of ways to combine $2 \times 4$ LEGO tiles, which in this case gives a 3-dimensional structure. In all cases the number of configurations is dominated by an exponential growth term, $μ^n$ where $n$ is the number of tiles. We present an algorithm for counting these various LEGO configurations, and use the data to estimate the asymptotics. We analyse the data so generated, and conjecture that, for the two-dimensional structures, the number of possible configurations grows like $A(w)μ(w)^n/n,$ and we give numerical estimates for $A(w)$ and $μ(w)$ for $w < 11,$ while for the three-dimensional structure the number of possible configurations is conjectured to grow like $Aμ^n/n^{3/2},$ where $μ= 117.25 \pm 0.05.$ We also study the sequences that arise when we fix the number of tiles $n,$ and vary the tile size $w.$ We prove that the sequences are polynomials of degree $n-1,$ and we give these explicitly for $n=1 \ldots 14.$

2605.07377 2026-05-11 econ.TH

Mental Health and Human Capital Composition in a Dynastic OLG Model with PAYG Pensions

Sushmita Kumari, Siddharth Gavhale

AI总结 本文构建了一个包含两期的代际重叠(OLG)模型,研究在现收现付(PAYG)养老金制度下,父母如何在消费、储蓄、生育及子女教育、身体和心理健康等多维质量投资之间进行决策。核心创新在于将心理健康建模为一种独立的、具有自身弹性参数的生产率提升要素,从而揭示养老金政策对人力资本总量及结构的影响。研究发现,提高PAYG缴费率虽会通过“雅吉塔效应”增加生育率,但会挤出对子女各维度质量的投资,特别是心理健康;而心理健康弹性参数的提升则会促进非认知技能发展,同时抑制生育率,凸显出发展中国家在养老保障与人力资本积累之间的政策矛盾。

Comments Accepted at the CDE-IEDS International Conference 2026, Delhi School of Economics (DSE), University of Delhi. 9 pages, 1 table

详情
英文摘要

This paper develops a two-period dynastic overlapping-generations (OLG) model in which parents simultaneously choose consumption, savings, fertility, and three distinct dimensions of child quality-education, physical health, and mental health-under a pay-as-you-go (PAYG) pension system. The central innovation is modelling mental health as an independent productivity-enhancing input with its own elasticity $θ$ in a Cobb-Douglas human-capital technology. This yields simple proportional allocation rules and shows how pension policy affects not only the overall level but also the composition of human capital investments. In steady state, higher PAYG contribution rates raise fertility through the Yakita effect but crowd out per-child investments in all quality dimensions, including mental health. An increase in the mental-health elasticity $θ$ shifts resources toward non-cognitive skill development while reducing fertility. These results reveal a fundamental policy tension for developing economies: pension systems that rely on children for old-age support simultaneously increase birth rates while reducing long-term human capital formation, with disproportionate effects on non-cognitive skills. The framework provides theoretical guidance for complementary policies that protect mental-health investments, with particular relevance for countries such as India where children remain a primary source of retirement security and mental-health services are underfunded.

2605.07376 2026-05-11 cs.SE

Low-code and no-code with BESSER to create and deploy smart web applications

Iván Alfonso, Armen Sulejmani, Aaron Conrardy, Jordi Cabot

AI总结 随着智能网页应用(含AI代理)需求的增长,研究提出了一种名为BESSER的开源低代码框架,旨在降低开发门槛并提升应用的可扩展性与透明度。该框架通过基于模型的组件抽象和自动化生成技术,支持用户通过网页编辑器设计、生成和部署应用,有效避免了商业平台带来的锁定风险。BESSER的主要贡献在于提供了一个开放、可扩展的解决方案,推动了智能网页应用的高效开发与部署。

Comments To appear in the tool track of the International Conference on Web Engineering (ICWE 2026)

详情
英文摘要

The increasing demand for web applications containing AI-agents, seen as smart web applications, has prompted the need for new techniques to facilitate their creation. Low-code has risen as an approach that reduces the amount of handwritten code by focusing on the abstraction of components in the form of models combined with automated generators to produce applications. Existing low-code platforms are commercial, leading to drawbacks such as the risk of vendor lock-in, limited extensibility, and more. We present the open-source BESSER low-code framework, which allows users to design, generate and deploy their application via a freely accessible web-based editor, while guaranteeing transparency and extensibility.

2605.07374 2026-05-11 quant-ph

Computational and physical complexity of synthesizing random multi-qudit quantum states and unitary operators

Sahel Ashhab, Bora Basyildiz

AI总结 本文研究了在多体量子系统中合成随机量子态和幺正算符的计算复杂度与物理复杂度。计算复杂度通过所需基本量子门的数量衡量,而物理复杂度则通过完成操作所需的最短时间衡量。研究发现,随机态或幺正算符的计算复杂度随量子体数量呈指数增长,而物理复杂度增长较慢,这对理解随机与伪随机量子态及算符的关系具有重要意义。

Comments 12 pages, 2 tables

详情
英文摘要

We analyze the complexity of synthesizing random states and unitary operators in a multi-qudit system in two paradigms. In one case, we consider the situation in which we manipulate the system by applying a sequence of one- and two-qudit quantum gates that constitute the elementary, and universal, gate set. The minimum number of gates required to perform the desired operation represents the computational complexity. In the other case, we consider the situation in which we manipulate the physical system using physical fields with optimized control pulses. The minimum time required to perform the desired operation represents the physical complexity. In both cases, we use analytical arguments in combination with optimal-control-theory numerical calculations to determine the complexity of random operations. We show that the computational complexity of random states or unitary operators scales exponentially with the number of qudits. Our numerical results suggest that the physical complexity of preparing random quantum states and unitary operators scales more slowly than the computational complexity. We discuss various implications of our results, especially concerning the relationship between random and pseudorandom states and unitary operators.

2605.07372 2026-05-11 cond-mat.quant-gas

Rabi-coupling-induced three-component quantum droplet in ultracold Bose gases

Xiao Ding, Dajun Wang, Xiaoling Cui

AI总结 本文提出了一种在超冷玻色气体中实现三组分量子滴的新机制,仅需一种组间相互作用为吸引性。通过拉比耦合,第三组分可与二元量子滴中的某一组分结合,增强的拉比耦合虽能增加第三组分的比例,但也会因引入更多排斥力而破坏系统稳定性,而适当的频率失配可有效缓解这一问题。研究通过热力学分析和扩展的Gross-Pitaevskii方程数值模拟,在实际的钠-铷混合系统中验证了该机制,为多组分量子滴的稳定实现提供了通用路径。

Comments 8 pages, 5 figures

详情
英文摘要

We uncover a new mechanism for realizing three-component quantum droplets in ultracold Bose gases, where only one inter-species interaction is attractive. In this scheme, the inter-species attraction leads to a self-bound binary droplet, and the third component joins through Rabi coupling with one component of the binary droplet. We find that a stronger Rabi coupling leads to a larger fraction of the third component, but also destabilizes the entire droplet due to the involvement of more repulsive forces. Such instability can be remedied by a finite detuning between the Rabi-coupled components. We demonstrate these results in realistic Na-Rb mixtures, using both thermodynamic analyses and numerical simulations based on extended Gross-Pitaevskii equations. Our work outlines a general route for stabilizing multi-component droplets by bridging an existing binary droplet with additional components via suitable single-particle fields.

2605.07371 2026-05-11 quant-ph

Breaking mechanical dark mode via the Coulomb interaction

Jian-Song Zhang, Yuan Chen, Guang-Ling Cheng, Ai-Xi Chen

AI总结 本文提出了一种通过库仑相互作用打破两个简并机械谐振子在光机械系统中“暗模”的方法。利用光学参量放大器和库仑相互作用引入的机械参量放大,能够在远离边带分辨区的条件下同时将两个简并机械谐振子冷却至基态,并生成超过3 dB的强而稳定的机械压缩。研究还表明,该方法能够实现稳健的两体及真正的三体纠缠,在简并光机械系统中具有重要应用价值。

Comments 7 pages, 3 figures

详情
Journal ref
Opt. Lett. 51, 2360-2363 (2026)
英文摘要

We propose a method to break the dark mode of two degenerate mechanical resonators (MRs) in optomechanical systems via the Coulomb interaction. Two degenerate MRs can be cooled to their ground-state simultaneously beyond the resolved sideband regime using the Coulomb interaction and an optical parametric amplifier (OPA). We show that strong and robust mechanical squeezing beyond 3 dB can be generated using the OPA and mechanical parametric amplification (MPA) introduced by the Coulomb interaction. Our results manifests that robust bipartite and genuine tripartite entanglement can be produced in a degenerate optomechanical system.

2605.07369 2026-05-11 math.PR

Moderate Deviation Principle for a Stochastic Approximation Process

Jianan Shi, Qing Yin, Yu Miao

AI总结 本文研究了一个取值于实数域的随机逼近过程 $(X_n)_{n\ge 0}$,该过程满足特定的递归关系,并适应于一个过滤序列。作者建立了该过程的中偏差原理,作为辅助结果,还得到了该过程的指数不等式以及有界鞅差加权和的中偏差原理。这一工作为理解随机逼近过程的渐进行为提供了重要的理论支撑。

Comments 22 pages, 0 figures

详情
英文摘要

In this paper, we investigate a stochastic approximation procedure $\left(X_n\right)_{n\ge 0}$ taking values in $R$. The process is adapted to a filtration $(F_n)_{n\ge 0}$ and satisfies the recursion $X_{n+1}=X_n+\frac{b}{n+1}\big[g(X_n)+U_{n+1}\big]$, where $b>0$, $g:R \to R$ is a function and $\left(U_n\right)_{n\ge 1}$ is a sequence of bounded martingale differences adapted to the filtration $(F_n)_{n\ge 1}$. We establish the moderate deviation principle for the stochastic process $(X_n)_{n\ge 0}$. As auxiliary results, we also obtain the exponential inequality for $(X_n)_{n\ge 0}$ and the moderate deviation principle for weighted sums of bounded martingale differences.

2605.07368 2026-05-11 eess.SP

Over-the-Air Beamforming Design for Full-Duplex Cell-Free Massive MIMO Systems

Bikshapathi Gouda, Antti Tölli

AI总结 本文研究了全双工无蜂窝大规模MIMO系统中的空中波束成形设计,针对分布式接入点(AP)全双工运行而用户设备(UE)半双工带来的自干扰、AP间耦合和UE间干扰问题,提出了一种基于迭代上下行导频信号的全分布式波束成形方案。该方法通过在导频域对接收信号进行投影,抑制干扰并提升AP波束成形的准确性,同时结合交替优化框架中的最佳响应更新策略,提升系统收敛性能。仿真结果表明,该方法在收敛速度和有效总速率方面优于传统方案,尤其在强干扰场景下优势明显。

Comments Submitted IEEE WCL

详情
英文摘要

We study a full-duplex (FD) cell-free massive MIMO system where distributed access points (APs) operate in FD mode while user equipments (UEs) remain half-duplex. Although simultaneous uplink (UL) and downlink (DL) transmissions improve spectral efficiency, they introduce residual self-interference, AP-to-AP coupling, and UE-to-UE cross-link interference. Building on prior over-the-air distributed beamforming frameworks, we develop a fully distributed beamforming design based on iterative UL and DL pilot signaling under a joint UL and DL sum mean-square error criterion that explicitly accounts for these interference components. In FD operation, simultaneous UL and DL pilot transmissions cause UE-to-UE pilot leakage, which contaminates the reconstruction of the cross terms required for AP-specific beamforming design. To mitigate this effect, we introduce a pilot-domain projection of the received signals at the UEs, which suppresses the interference component and enables accurate cross-term reconstruction at the APs. In addition, best-response updates at the UEs are employed within the alternating optimization framework to improve convergence under strong UE-to-UE interference. Numerical results demonstrate faster convergence and higher effective sum rate, with particularly significant gains for strongly interfering UEs, compared with both separate UL and DL distributed OTA beamforming training schemes and designs based solely on local channel state information.

2605.07365 2026-05-11 math.NA cs.NA

Solving Convolution-type Integral Equations using Preconditioned Neural Operators

Raymond Chan, Lingfeng Li

AI总结 本文研究了卷积型积分方程的求解问题,针对传统数值方法在处理高频误差分量时效率较低的问题,提出了一种基于预处理神经算子的新方法。通过引入预处理策略,设计了一种高效的神经算子训练方案,并将其与经典迭代求解器结合,构建出一种混合迭代算法。实验表明,该算法在求解大规模和病态线性系统时,在迭代次数和计算时间上均优于多网格方法和预处理共轭梯度法。

详情
英文摘要

Convolution-type integral equations arise from various fields, \textit{e.g.}, finite impulse response filters in signal processing and deblurring problems in image processing. When solving these equations, conventional numerical methods, like the multigrid method, can only efficiently solve the low-frequency components in the error, but not the high-frequency components. In this paper, we apply neural operators to address this issue. By adopting a preconditioning approach, we propose a novel training strategy that trains neural operators to solve the high-frequency components efficiently. Then, we combine the neural operators with some classical iterative solvers, like the weighted Jacobi method, to obtain an efficient hybrid iterative algorithm for the integral equations. We analyze the generalization error of our training strategy and the convergence of the hybrid iterative algorithm. We test our algorithms on large-scale and ill-conditioned linear systems discretized from one- and two-dimensional convolution-type integral equations. Our proposed algorithm significantly outperforms the multigrid method and the preconditioned conjugate gradient method in both iteration numbers and computational time.

2605.07362 2026-05-11 stat.ME

Sufficient Dimension Reduction via Inverse Conditional Mean or Variance Independence

Jicai Liu, Yu Zhang, Jinhong Li

AI总结 本文提出了一种统一的充分维数约减(SDR)框架,推广了多种现有SDR方法,并揭示了逆条件矩独立性与维数约减之间的新联系。该框架基于响应向量与预测变量之间的两种逆独立性形式——逆条件均值独立(ICMI)和逆条件方差独立(ICVI),分别构建了两类能够恢复中心子空间的矩阵,从而得到四种不同的估计方法。理论分析表明这些方法在高维条件下具有良好的收敛性质,且对响应变量中的异常值具有鲁棒性,仿真实验和实际数据分析验证了其有效性。

详情
英文摘要

This paper presents a unified framework for sufficient dimension reduction (SDR) that generalizes several existing SDR techniques and offers new insights into the connection between inverse conditional moment independence and dimension reduction. The framework is built on two forms of inverse independence between the response vector and predictors: inverse conditional mean independence (ICMI) and inverse conditional variance independence (ICVI). For each form, we develop two general classes of matrices capable of recovering the central subspace, based on projection and kernel techniques respectively. This yields four distinct estimators: projection- and kernel-based variants under both ICMI and ICVI frameworks. Under standard regularity conditions, we establish the theoretical properties of these estimators and derive their convergence rates in high-dimensional settings. The proposed methods exhibit robustness to outliers in the response variable while maintaining computational competitiveness. Simulation studies and real-data analyses demonstrate the practical effectiveness of the proposed methods.

2605.07352 2026-05-11 q-fin.GN

Corporate transparency and the disposition effect

Siliu Chen, Fei Ren

AI总结 本文研究了公司层面的透明度对个人投资者处置效应的影响。研究发现,公司透明度的提高显著降低了投资者过早卖出盈利资产而长期持有亏损资产的非理性行为。进一步分析表明,透明度增强时,投资者在持有盈利股票时信心提升,减少卖出倾向;而在持有亏损股票时,尽管信心减弱,但投资者更倾向于认为亏损是暂时的,从而加剧了持有亏损资产的倾向。总体来看,公司透明度的提升对减少处置效应具有显著作用。

详情
Journal ref
Front. Psychol. 16:1626829
英文摘要

The disposition effect describes investors' irrational behavior of selling profitable assets too soon while holding onto losing assets for too long. This study examines the impact of transparency at the firm level on the disposition effect of individual investors who hold that company's stock. Our results show that an increase in corporate transparency significantly reduces the disposition effect. Further analysis reveals that for companies with greater transparency, when the held stock is profitable, investors' confidence in holding it increases, leading to a reduced bias toward selling profitable stocks. When the stock is held at a loss, investors' confidence in holding it weakens, but they often perceive the loss as temporary and maintain confidence in the company's long-term prospects, thus exacerbating the bias toward holding losing stocks. The effect of increased transparency on the selling behavior of profitable stocks is greater than its effect on the selling behavior of losing stocks. Overall, an increase in corporate transparency significantly reduces the disposition effect.

2605.07350 2026-05-11 math.AP

Global Existence of Classical Solutions to Brenner-Navier-Stokes-Fourier System for Large Data

Saehoon Eo, Namhyun Eun, Moon-Jin Kang

AI总结 本文研究了一维Brenner-Navier-Stokes-Fourier(BNSF)系统,该系统通过引入体积速度对经典Navier-Stokes-Fourier模型进行了改进。文章在拉格朗日质量坐标下,利用体积速度与质量速度之间的差异建立了质量守恒方程中的耗散结构,并证明了对于任意大的初始数据,该系统存在全局经典解。研究中通过建立体积比的上下界,并结合抛物型De Giorgi方法和最大值原理,克服了主要困难,得到了解的全局存在性及正则性保持的结果。

详情
英文摘要

We study the 1D Brenner-Navier-Stokes-Fourier (BNSF) system, proposed as a refinement of the classical Navier--Stokes--Fourier model through the introduction of the volume velocity, distinct from the mass velocity describing convective transport. When formulated in the Lagrangian mass coordinates with the volume velocity, the discrepancy between the two velocities induces a dissipative structure in the mass conservation law. We prove the global existence of classical solutions for arbitrarily large initial data. More precisely, for initial data in $H^k(\mathbb{R})$ with $k\ge3$, with the specific volume and absolute temperature initially bounded away from zero, we construct global-in-time solutions that remain in the same regularity class. Our result accommodates arbitrarily large initial data. A major difficulty is to establish lower and upper bounds for the specific volume \(v\). The additional dissipation yields an $L_t^2 L_x^2$ bound for $v_x$, which is further improved to an $L_t^\infty L_x^\infty$ bound of $v$ and $1/v$ via the parabolic De Giorgi method. We also apply the maximum principle to obtain a positive lower bound for the absolute temperature.

2605.07349 2026-05-11 cs.DS

Optimal Learning-Augmented Algorithm for Online Bidding

Changyeol Lee, Dahoon Lee, Jongseo Lee, Yongho Shin, Changki Yun

AI总结 本文研究了在线竞价问题中的学习增强算法,旨在平衡算法的鲁棒性与一致性。作者提出了一种帕累托最优的随机学习增强算法,填补了随机设置下上界与下界之间的理论空白。该方法引入了“竞价分布”这一新框架,并通过延迟微分方程刻画最优分布,同时将该方法推广到线性搜索问题,取得了优于现有算法的显著改进。

详情
英文摘要

Recent advances in machine learning have spurred significant interest in learning-augmented algorithms, particularly for online optimization. A growing body of work has studied online bidding in this framework, aiming to characterize the trade-off between robustness and consistency. While this trade-off is fully understood for deterministic algorithms, a gap between upper and lower bounds remains in the randomized setting. In this paper, we close this gap by presenting a Pareto-optimal randomized learning-augmented algorithm for this problem. Our approach introduces the notion of a bidding profile, a novel framework for representing the distribution over bids generated by an algorithm. We show that any bidding algorithm can be reduced, without loss of generality, to one driven by a bidding profile, and we characterize the optimal profile via a system of delayed differential equations. Finally, we demonstrate the broader applicability of our approach by extending it to the linear search problem, yielding a significant improvement over prior learning-augmented algorithms for linear search.

2605.07348 2026-05-11 hep-ph hep-th

Generalizations and UV completions of Cho-Maison monopole

Fukutaro Miya, Ryosuke Sato

AI总结 本文研究了Cho-Maison磁单极子在电弱理论中的推广及其在更广泛规范理论中的构造方法,展示了类似磁单极子配置可以在包含电弱对称破缺结构的模型中出现。研究还表明,Cho-Maison磁单极子可以作为’t Hooft-Polyakov磁单极子在低能极限下的有效描述,并在帕提-萨拉姆模型中验证了这一行为,为理解磁单极子的紫外完备性提供了新视角。

Comments 25 pages, 4 figures

详情
英文摘要

A monopole configuration in the electroweak theory was constructed by Cho and Maison, allowing for a singular behavior at the origin. Since the essential structure of the Cho-Maison monopole is based on an electroweak-type symmetry breaking, similar monopole configurations are expected to arise more generally in gauge theories containing such a structure. In this paper, we explicitly show that Cho-Maison-like monopole configurations can indeed be constructed in a broad class of models. We also show that the Cho-Maison monopole can be embedded into an 't Hooft-Polyakov monopole as its low-energy effective description. In particular, we find that a monopole in the Pati-Salam model behaves as the electroweak Cho-Maison monopole once degrees of freedom which are heavier than the electroweak scale are integrated out.

2605.07347 2026-05-11 math.NA cs.NA math.AP

Convergence of an Eulerian scheme for the Vlasov-Poisson-BGK model

Seung Yeon Cho, Sungsu Park, Seok-Bae Yun

AI总结 本文研究了Vlasov-Poisson-BGK模型的欧拉方法的收敛性,该模型用于描述碰撞等离子体的动力学行为。针对现有数值方法缺乏收敛性理论的问题,作者首次对一个非分裂的有限差分欧拉方案进行了收敛性分析,该方案在完整的相空间网格上进行离散。为克服电场引起的速度指标混合带来的稳定性挑战,作者提出了一种适用于电离系统的改进下界估计方法,并在截断速度域和Neumann边界条件下,分别得到了分布函数在加权$L^\infty$范数和电场在$L^\infty$范数下的误差估计。

Comments 52 pages, 1 figure

详情
英文摘要

The Vlasov-Poisson-BGK (VPBGK) model is a kinetic model for describing the dynamics of collisional plasmas. Although various numerical schemes have been developed for it, a corresponding convergence theory has been absent. This paper fills this gap by presenting the first convergence analysis for a non-splitting, finite-difference Eulerian scheme discretized on the full phase-space grid. A major theoretical obstacle is the mixing of velocity indices induced by the electric field, which hinders the derivation of a uniform lower bound for the discrete solution. To overcome this stability challenge, we propose a modified lower bound estimate suitable for ionized systems that incorporates the step-wise degradation. Under a truncated velocity domain with a Neumann boundary condition, we establish error estimates for the distribution function in a weighted $L^{\infty}$ norm and for the electric field in a $L^{\infty}$ norm, respectively.