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2604.12423 2026-05-08 math.AP

Norm inflation and low-regularity ill-posedness for the rod equation

细长杆方程的范数膨胀与低正则性不恰当性

Jinlu Li, Yanghai Yu

AI总结 本文通过构造显式光滑初值,证明在H^s(R)中1<s<3/2范围内,细长杆方程的初值问题在范数膨胀意义下不恰当,即初始数据在H^s(R)中光滑且任意小,但解在任意短时间后变得任意大。

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AI中文摘要

在本文中,我们考虑了细长杆方程在直线上的柯西问题。通过构造显式光滑初值,我们提出了一种新方法,证明该问题在H^s(R)中1<s<3/2范围内在范数膨胀意义下不恰当,即初始数据在H^s(R)中光滑且任意小,但解在任意短时间后在Sobolev空间中变得任意大。

英文摘要

In this paper, we consider the Cauchy problem for the rod equation in the line. By constructing an explicit smooth initial data, we present a new method to prove that this problem is ill-posed in $H^s(\R)$ with $1< s<3/2$ in the sense of {\it norm inflation}, i.e., an initial data is smooth and arbitrarily small in $H^s(\R)$ with $1< s<3/2$, but the solution becomes arbitrarily large in the Sobolev space after an arbitrarily short time.

2604.11409 2026-05-08 quant-ph

When T-Depth Misleads: Predicting Fault-Tolerant Quantum Execution Slowdown under Magic-State Delivery Constraints

当T深度误导:在魔态交付限制下预测容错量子执行延迟

Boshuai Ye, Arif Ali Khan, Peng Liang

AI总结 本文提出通过slack ratio和Delta_max预测量子执行延迟,揭示静态T深度无法准确预测执行性能,实验证明Delta_max是预测延迟的最强指标。

Comments 10 pages, 10 figures. Code available at https://github.com/C2-Q/BARC/

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AI中文摘要

容错量子算法的高效执行受限于非Clifford操作所需魔态的生成速率。尽管电路优化通常针对T深度,但静态T深度不能可靠预测在受限T态交付下的执行性能。我们引入一个模型,利用slack ratio(调度灵活性的结构指标)和Delta_max(累计需求过剩的度量)来捕捉供需不平衡。我们证明Delta_max是执行延迟的强预测指标,并为固定调度提供可证明的执行时间下界。对构造的有向无环图(DAG)家族进行实证评估,结合算术电路和精确量子傅里叶变换(QFT)轨迹提供额外支撑,结果显示slack ratio比T深度更能预测停滞和反向风险,而Delta_max是预测延迟的最强指标。在4904个实例中,下界无违反,88.9%的案例在1个周期内。这些结果突显了在容错量子编译中显式建模交付限制的重要性。

英文摘要

The efficient execution of fault-tolerant quantum algorithms is fundamentally limited by the production rate of magic states required for non-Clifford operations. While circuit optimization typically targets T-depth, static T-depth does not reliably predict executable performance under bounded T-state delivery. We introduce a model that captures demand-supply imbalance using two key quantities: slack ratio, a structural indicator of scheduling flexibility, and Delta_max, a measure of cumulative demand surplus. We show that Delta_max is a strong schedule-level indicator of execution slowdown and yields a provable lower bound on executable makespan for a fixed schedule. Empirical evaluation on constructed directed acyclic graph (DAG) families, with arithmetic circuits and exact quantum Fourier transform (QFT) traces providing additional grounding, shows that slack ratio is a stronger structural predictor than T-depth for stall and inversion risk, while Delta_max is the strongest predictor of slowdown. Across 4,904 instances, the lower bound shows zero violations, with 88.9% of cases within one cycle. These results highlight the importance of explicitly modeling delivery constraints in fault-tolerant quantum compilation.

2604.09471 2026-05-08 math.QA math-ph math.MP math.RT

Fundamental fields in the deformed $W$-algebras

变形W代数中的基本场

Hicham Assakaf

AI总结 本文提出了一种新的框架,用于重新表述和证明一种生成变形W代数元素的算法,并证明了在B、C型及其他类型中Frenkel和Reshetikhin的猜想。

Comments 60 pages

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AI中文摘要

设$\mathfrak{g}$为一个简单李代数。Frenkel和Reshetikhin引入了变形W代数$\mathbf{W}_{qt}(\mathfrak{g})$。本文提出了一种不同的上下文中的正式重述方法。在此框架下,我们重新表述并证明了受Frenkel-Mukhin算法启发的算法的正确性(arxiv:2103.15247, arxiv:2205.08312),该算法从给定的主多项式$m$出发,生成变形W代数的元素。然后,我们应用该算法显式地构造了一些特定的$\mathbf{W}_{q,t}(\mathfrak{g})$元素。特别是,我们应用该算法证明了Frenkel和Reshetikhin在arXiv:q-alg/9708006中在B$_\ell$、C$_\ell$类型以及某些其他类型节点中的猜想。此框架为研究变形W代数$\mathbf{W}_{q,t}(\mathfrak{g})$中的场提供了新的可能性。

英文摘要

Let $\mathfrak{g}$ be a simple Lie algebra. Frenkel and Reshetikhin introduced the deformed $W$-algebra $\mathbf{W}_{qt}(\mathfrak{g})$. In this work, we propose a formal reformulation of this definition in a different context. In this framework, we reformulate and prove the well-definedness of an algorithm (arxiv:2103.15247, arxiv:2205.08312) inspired by the Frenkel-Mukhin algorithm (arXiv:math/9911112) which, starting from a given dominant monomial $m$ satisfying some degree conditions, produces elements of the deformed $W$-algebra. Then, we apply this algorithm to construct explicitly some specific elements of $\mathbf{W}_{q,t}(\mathfrak{g})$. In particular, we apply this to prove a conjecture of Frenkel and Reshetikhin in arXiv:q-alg/9708006 in types $B_\ell$, $C_\ell$, and for some nodes in other types. This framework opens up new possibilities for studying explicitly fields in the deformed $W$-algebra $\mathbf{W}_{q,t}(\mathfrak{g})$.

2604.08127 2026-05-08 math.PR

Asymptotics of Brownian occupation measures with unusually large intersections

布朗运动占用测度的渐进行为与其异常大交集

Jiyun Park

AI总结 研究布朗运动在大交集条件下占用测度的弱收敛性,通过大偏差原理证明其密度为Gagliardo-Nirenberg不等式优化解的平方,推导了无条件布朗运动占用测度的紧致大偏差原理,并证明了倾斜后的大偏差原理。

Comments 32 pages, minor changes

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AI中文摘要

我们证明了条件为大交集的布朗运动占用测度在空间平移下弱收敛到密度为Gagliardo-Nirenberg不等式优化解平方的测度。为此,我们证明了布朗运动占用测度在大自交集或大互交集条件下的大偏差原理。为此,我们推导了无条件布朗运动占用测度的紧致大偏差原理,扩展了Mukherjee和Varadhan的工作。我们还证明了在相同拓扑下,布朗运动占用测度倾斜于其交集的大偏差原理。一个独立有用的工具是交集测度对所有有界可测函数的指数良好近似,从而进一步得到独立布朗运动交集测度的大偏差原理。

英文摘要

We prove that the occupation measures of Brownian motions conditioned to have large intersections converge weakly, up to spatial shifts, to the measure whose density is the square of an optimizer of the Gagliardo-Nirenberg inequality. We do so by proving a large deviation principle (LDP) for Brownian occupation measures conditioned either on large self-intersections or large mutual intersections. To this end, we derive a compact LDP for unconditioned Brownian occupation measures, generalizing the work of Mukherjee and Varadhan. We also prove the LDP for Brownian occupation measures tilted by their intersections in the same topology. A key tool of independent interest is an exponentially good approximation of the intersection measure tested against all bounded measurable functions, from which we further get the LDP for the intersection measure of independent Brownian motions.

2604.03974 2026-05-08 cs.DC

Lemonshark: Asynchronous DAG-BFT With Early Finality

Lemonshark:异步DAG-BFT与早期最终性

Michael Yiqing Hu, Alvin Hong Yao Yan, Yang Yihan, Liu Xiang, Li Jialin

AI总结 Lemonshark提出一种异步DAG-BFT协议,通过交易层面重构DAG并确定承诺非必要但安全的条件,实现提前最终化,降低延迟达65%。

Journal ref Proceedings of the 23rd USENIX Symposium on Networked Systems Design and Implementation 2026

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AI中文摘要

DAG-Rider推广了DAG-BFT协议的新范式,将传播与共识分离:所有节点将交易作为块传播,块引用先前已知的块,而共识通过选举某些块为领导者达成。此设计提高了吞吐量,但只有领导者块具有最优延迟;非领导者块不能独立提交。我们提出Lemonshark,一种异步DAG-BFT协议,通过交易层面重构DAG并确定承诺足够但非必要的条件,使节点可在官方提交前最终化交易,不牺牲正确性。与现有最佳异步BFT协议相比,Lemonshark将延迟降低了高达65%。

英文摘要

DAG-Rider popularized a new paradigm of DAG-BFT protocols, separating dissemination from consensus: all nodes disseminate transactions as blocks that reference previously known blocks, while consensus is reached by electing certain blocks as leaders. This design yields high throughput but confers optimal latency only to leader blocks; non-leader blocks cannot be committed independently. We present Lemonshark, an asynchronous DAG-BFT protocol that reinterprets the DAG at a transactional level and identifies conditions where commitment is sufficient -- but not necessary -- for safe results, enabling nodes to finalize transactions before official commitment, without compromising correctness. Compared to the state-of-the-art asynchronous BFT protocol, Lemonshark reduces latency by up to 65\%.

2604.03828 2026-05-08 astro-ph.CO

Beyond $f(ϕ)\mathcal{G}$: Gauss--Bonnet inflation with $μ(ϕ,X)$

超越f(ϕ)G:Gauss–Bonnet膨胀与μ(ϕ,X)

Ali Seidabadi, Sara Saghafi, Kourosh Nozari

AI总结 本文提出一种选择性耦合μ(ϕ,X),使Gauss–Bonnet项在相空间中局部化,从而在有限e-fold窗口内产生高曲率贡献,同时保持其他区域的微小性,并分析其对CMB测量的影响。

Comments 21 pages, 17 figures, 6 tables, Accepted for Publication in EPJC

Journal ref Eur. Phys. J. C 86, 442 (2026)

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AI中文摘要

Gauss–Bonnet膨胀通常影响轨迹的延长部分,使得在CMB尺度上难以孤立可控的印记。我们考虑一种轨迹选择性耦合μ(ϕ,X),在相空间中控制Gauss–Bonnet部分,使高曲率贡献被限制在有限的e-fold窗口内,同时在其他区域保持微小。我们识别出与这种局部化一致的稳定膨胀解,并强制标准的鬼和梯度稳定性条件,适用于标量和张量扰动。对于这些可行背景,我们计算了pivot尺度可观测变量,并检验其对整体Gauss–Bonnet强度和动能门控的依赖性。该框架提供了一种受控的方法,以实现局部化的高曲率效应,并对CMB尺度测量产生可预测的影响。

英文摘要

Gauss--Bonnet inflation typically affects the dynamics over an extended portion of the trajectory, making it difficult to isolate a controlled imprint at CMB scales. We consider a trajectory-selective coupling \(μ(ϕ,X)\) that gates the Gauss--Bonnet sector in phase space, enabling the higher-curvature contribution to be localized within a finite e-fold window while remaining negligible elsewhere. We identify stable inflationary solutions consistent with this localization and enforce standard ghost and gradient stability conditions for both scalar and tensor perturbations. For these viable backgrounds we compute pivot-scale observables and examine their dependence on the overall Gauss--Bonnet strength and on the kinetic gating. The framework offers a controlled route for realizing localized higher-curvature effects with predictable consequences for CMB-scale measurements.

2604.02326 2026-05-08 eess.SP

ReVAR: A Data-Driven Algorithm for Generating Aero-Optic Phase Screens

ReVAR:一种数据驱动的生成气动-光学相屏算法

Jeffrey W. Utley, Gregery T. Buzzard, Charles A. Bouman, Matthew R. Kemnetz

AI总结 本文提出ReVAR算法,通过长程自回归模型和空间白化步骤生成符合实测数据统计的合成气动-光学相屏数据,优于传统方法。

Comments 21 pages, 7 figures. Submitted to JOSA A for the pcAOP Feature Issue

Journal ref J. Opt. Soc. Am. A (2026)

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AI中文摘要

光通过飞机周围湍流流动场的传播导致称为气动-光学效应的光学畸变。开发缓解这些效应的方法需要大量真实的气动-光学数据。然而,获取此类数据的方法,包括实验、计算流体动力学和简单的相屏算法(如沸腾流),都存在显著缺点,如成本高、计算量大、数量有限以及统计不准确。更近期,提出了一种数据驱动的算法,计算效率高,能够合成气动-光学数据以匹配测量数据的统计特性,但这些方法仍存在局限性,包括质量有限、统计不准确以及使用复杂的算法。本文介绍ReVAR(Re-whitened Vector AutoRegression),一种数据驱动的生成合成气动-光学数据的算法,该数据能匹配测量数据的统计特性。该算法的一个关键贡献是长程自回归,一种结合标准自回归和数据集的一组低通滤波器的线性预测模型,以拟合短程和长程时间统计。ReVAR利用长程AR与空间白化步骤将测量的气动-光学数据转换为时间上和空间上不相关的白噪声。ReVAR随后通过使用白噪声输入反向此过程来生成合成的气动-光学数据。使用两个测量的湍流边界层数据集,我们证明ReVAR在匹配测量数据的时间功率谱和其他关键指标方面优于两种传统相屏生成方法和一个现有的单时间滞后自回归模型。

英文摘要

The propagation of light through a turbulent flow field around an aircraft results in optical distortions commonly known as aero-optic effects. The development of methods to mitigate these effects requires large amounts of realistic aero-optic data. However, methods for obtaining this data, including experiment, computational fluid dynamics, and simple phase screen algorithms (e.g., boiling flow), each have significant drawbacks such as high cost, high computation, limited quantity, and/or inaccurate statistics. More recently, data-driven algorithms have been proposed that are computationally efficient and can synthesize aero-optic data to match the statistics of measured data, but these approaches still have drawbacks including limited quality, inaccurate statistics, and the use of complicated algorithms. In this paper, we introduce ReVAR (Re-whitened Vector AutoRegression), a data-driven algorithm for generating synthetic aero-optic data that matches the statistics of measured data. A key contribution in this algorithm is Long-Range AutoRegression, a linear predictive model that combines a standard autoregression with a set of low-pass filters of the data to fit both short-range and long-range temporal statistics. ReVAR uses Long-Range AR together with a spatial re-whitening step to convert measured aero-optic data to temporally and spatially un-correlated white noise. ReVAR can then generate synthetic aero-optic data by reversing this process using white noise input. Using two measured turbulent boundary layer data sets, we demonstrate that ReVAR better matches the measured data's temporal power spectrum and other key metrics than do two conventional phase screen generation methods and an existing single time-lag autoregressive model.

2603.29714 2026-05-08 math.AC

Toward the theory on local cohomologies at the ideals given by simplicial posets

走向由simplicial poset给出的理想局部余维理论

Kosuke Shibata, Kohji Yanagawa

AI总结 本文研究了由simplicial poset给出的理想局部余维理论,通过构造和分析渐进注射包络来建立局部余维的理论基础。

Comments 20 pages. Abstract and Introduction revised

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AI中文摘要

对于simplicial poset P,Stanley将面环A_P定义为多项式环S: = K[t_x | x ∈ P \ {0} ]对理想I_P的商环。这是Stanley-Reisner环的推广,但S和A_P在此情况下不是标准分层的,且I_P不是单项理想。为了建立局部余维H_{I_p}^i(S)及其投射解析的理论基础,我们给出了渐进注射包络{}^*E_S(S/ p_x)的显式描述,其中p_x是与x ∈ P相关的素理想,并分析了它们在渐进对偶复形中的行为。

英文摘要

For a simplicial poset $P$, Stanley assigned the face ring $A_P$, which is the quotient of the polynomial ring $S:=K[t_x \mid x \in P \setminus \{\widehat{0} \}]$ by the ideal $I_P$. This is a generalization of Stanley-Reisner rings, but $S$ and $A_P$ are not standard graded in this case, and $I_P$ is not a monomial ideal. To establish the foundation of the theory on local cohomology $H_{I_p}^i(S)$ and its injective resolution, we give an explicit description of the graded injective envelope ${}^*\! E_S(S/\mathfrak{p}_x)$, where $\mathfrak{p}_x$is the prime ideal associated with $x \in P$, and analyze their behavior in the graded dualizing complex.

2603.29325 2026-05-08 hep-ph nucl-th

Baryonic vortices in rotating nuclear matter

重子涡流在旋转核物质中的研究

Kazuya Mameda, Muneto Nitta, Zebin Qiu

AI总结 本文研究了旋转核物质中重子涡流作为拓扑激发态的性质,通过Chiral扰动理论分析了局部和全局涡流的拓扑电荷,并探讨了其在有限尺寸系统中的物理有效性。

Comments 17 pages, 3 figures

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AI中文摘要

我们通过Chiral扰动理论框架研究了旋转核物质中的重子涡流作为拓扑激发态。我们识别出两种不同的配置:局部和全局涡流,两者均携带重子数作为与第三同调群π_3(S^3)相关的拓扑电荷。对于局部涡流,类似于有限异旋化化学势下的涡旋Skyrmion,带电π介子在边界形成凝聚态并具有相位缠绕,而中性π介子沿旋转轴内部变化。另一方面,全局涡流由中性π介子的凝聚态和相位缠绕形成,而带电π介子在内部沿旋转轴变化。关键的是,尽管全局涡流在无限系统中通常因能量发散而被排除,我们证明了在旋转框架中由因果性决定的有限尺寸约束可物理地调节发散,使全局涡流成为可行激发态。我们揭示了全局和局部涡流状态之间的能量竞争,受旋转、系统尺寸和重子化学势等可调参数影响。我们的结果表明,此前被忽视的全局涡流在旋转密集QCD物质的拓扑结构中可能扮演重要角色。

英文摘要

We investigate baryonic vortices as topological excitations in rotating nuclear matter within the framework of chiral perturbation theory. We identify two distinct configurations: local and global vortices, both carrying the baryon number as the topological charge associated with the third homotopy group $π_3(S^3)$. For the local vortex, similar to the vortex Skyrmion in a finite isospin chemical potential, charged pions form the condensate on the boundary and have a phase winding, while the neutral pion varies along the rotation axis inside the vortex core. On the other hand, a global vortex is formed by the condensate and phase winding of the neutral pion, while the charged pions vary on the inside along the rotation axis. Crucially, although global vortices are usually discarded in infinite systems due to logarithmic divergence in energy, we demonstrate that the finite-size constraint dictated by causality in a rotating frame regularizes the divergence physically, rendering the global vortex a viable excitation. We reveal an energetic competition between global and local vortex states, under the tunable parameters of rotation, system size, and baryon chemical potential. Our results suggest that the previously overlooked global vortex can play a significant role in the topological structure of rotating dense QCD matter.

2603.29290 2026-05-08 quant-ph

A Universal Topological Platform for Nonreciprocal Spin-Photon Interface in Solid-State Quantum Networks

一种通用的拓扑平台用于固态量子网络中的非 reciprocal 自旋-光子接口

Fang-Yu Hong

AI总结 本文提出了一种基于单壁碳纳米管微环的等离子体平台,利用Tomonaga-Luttinger液体实现强光-物质耦合、确定性非 reciprocal 光子路由和高效提取,通过拓扑保护实现高保真度的自旋-光子纠缠。

Comments 23 pages, 6 figures

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AI中文摘要

固态量子网络可扩展性的根本障碍在于缺乏提供强光-物质耦合、确定性非 reciprocal 光子路由和高效提取的通用接口。本文提出了一种基于单壁碳纳米管微环的等离子体平台,利用单壁碳纳米管中的Tomonaga-Luttinger液体(TLL)克服这些挑战。TLL的集体玻色子激发通过大谷-动量不匹配被动能学保护,从而保证了无法在介电腔中实现的鲁棒自旋-动量锁定。这种一维保护使圆偏振光子从量子发射器(如氮空位中心)确定性地路由到不同的传播通道。通过对发射器对称轴的对齐,寄生π跃迁被几何禁止。此外,通过静电偏置和退火将残余原子级反散射抑制到约100 Hz。为克服CNT等离子体与光纤之间的严重模式不匹配,我们引入了梯度等离子体-光子模式转换器,提供了接近单位提取效率的路径。利用三脚架-STIRAP方案,我们展示了高保真度、磁性可调的自旋-光子纠缠。我们的分析证实了在强耦合区域内操作,合作度C>100,手性对比度超过20 dB。这种波长无关的架构与任何固态发射器兼容,为全球量子互联网中的稳健、非 reciprocal 量子节点提供了可扩展的蓝图。

英文摘要

A fundamental obstacle to scalable solid-state quantum networks is the lack of a universal interface providing strong light-matter coupling, deterministic nonreciprocal photon routing, and efficient extraction. Here we propose a plasmonic platform overcoming these challenges using a Tomonaga-Luttinger liquid (TLL) in a single-walled carbon nanotube (SWCNT) microtoroid. The TLL's collective bosonic excitations are kinematically protected against backscattering by a large valley-momentum mismatch, guaranteeing robust chiral spin-momentum locking unattainable in dielectric cavities. This 1D protection enables deterministic routing of circularly polarized photons from a quantum emitter (e.g., a nitrogen-vacancy center) into distinct propagation channels. By aligning the emitter's symmetry axis, parasitic π transitions are geometrically forbidden. Furthermore, residual atomic-scale backscattering is suppressed to ~100 Hz via electrostatic gating and annealing. To overcome the severe mode mismatch between the CNT plasmon and optical fiber, we introduce a graded plasmonic-photonic mode converter, providing a path to near-unity extraction efficiency. Using a tripod-STIRAP scheme, we demonstrate high-fidelity, magnetically tunable spin-photon entanglement. Our analysis confirms operation deep in the strong-coupling regime, with cooperativities C > 100 and chiral contrast exceeding 20 dB. This wavelength-agnostic architecture is compatible with any solid-state emitter, establishing a scalable blueprint for robust, nonreciprocal quantum nodes in a global quantum internet.

2603.27701 2026-05-08 math.AP

On principal eigenpairs for the (p,q)-Laplacian in exterior domain

关于外域中(p,q)-拉普拉斯主特征对的问题

Maya Chhetri, Pavel Drabek, Ratnasingham Shivaji

AI总结 研究了外域中(p,q)-拉普拉斯方程的特征值问题,证明了主特征值及其对应的特征函数的存在性、正则性及渐进行为。

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AI中文摘要

我们考虑了以下特征值问题:在Ω^e中,-Δ_p u -Δ_q u = λK(x)|u|^{p-2}u,边界上u=0,且当|x|→∞时u(x)→0。其中Ω^e是bounded domain Ω的外域,p,q∈(1,N)且p≠q,0<K∈L^∞(Ω^e)∩L^{N/p}(Ω^e),λ∈R。我们建立了主特征值的无界集及其对应特征函数的存在性。此外,我们证明了这些特征函数关于特征值参数λ的正则性、正性和渐进行为。我们使用S.I. Pohozaev的纤维化方法来证明我们的结果。

英文摘要

We consider an eigenvalue problem of the form \begin{equation*} \left\{\begin{array}{rclll} -Δ_{p} u -Δ_{q} u&=& λK(x)|u|^{p-2}u & \mbox{ in } Ω^e u&=&0\qquad \quad &\mbox{ on } \partial Ω u(x) &\to& 0 &\mbox{ as } |x| \to \infty\,, \end{array}\right. \end{equation*} where $Ω^e$ is the exterior of a simply connected, bounded domain $Ω$ in $\mathbb{R}^N$, $p, q \in (1, N)$ with $p \neq q$, $0 < K \in L^{\infty}(Ω^e) \cap L^{\frac{N}{p}}(Ω^e)$, and $λ\in \mathbb{R}$. We establish the existence of an unbounded set of the principal eigenvalues and corresponding eigenfunctions. Moreover, we establish the regularity, positivity and the asymptotic profiles of these eigenfunctions with respect to the eigenvalue parameter $λ$. We use the {\em fibering method} of S.~I. Pohozaev to prove our results.

2603.27374 2026-05-08 eess.SY cs.SY

Safe Adaptive-Sampling Control via Robust M-Step Hold Model Predictive Control

安全自适应采样控制 via robust M-step hold 模型预测控制

Spencer Schutz, Charlott Vallon, Francesco Borrelli

AI总结 本文提出 robust M-step hold 模型预测控制方法,用于确保自适应采样控制的安全性,通过递归可行性分析和在线选择 M 实现安全控制,通过 cruise control 示例验证了方法的有效性。

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AI中文摘要

在自适应采样控制中,控制频率可以在任务执行过程中调整。确保这些调整不会危及被控系统的安全性需要关注。我们引入了 robust M-step hold 模型预测控制(MPC)来解决这个问题。我们的公式为具有固定采样时间的不确定离散时间系统模型提供了鲁棒约束满足,该模型受可调节的多步输入保持(称为 M-step hold)影响。我们展示了如何利用 M-step hold 扩展的鲁棒不变集来确保 MPC 的递归可行性,并展示了如何通过在线选择 M 来实现安全自适应采样控制。我们通过 cruise control 示例评估了 robust M-step hold MPC 公式的作用。

英文摘要

In adaptive-sampling control, the control frequency can be adjusted during task execution. Ensuring that these changes do not jeopardize the safety of the system being controlled requires attention. We introduce robust M-step hold model predictive control (MPC) to address this. Our formulation provides robust constraint satisfaction for an uncertain discrete-time system model with a fixed sampling time subject to an adaptable multi-step input hold (referred to as M-step hold). We show how to ensure recursive feasibility of the MPC utilizing M-step hold extensions of robust invariant sets, and demonstrate how to enable safe adaptive-sampling control via the online selection of M. We evaluate the utility of the robust M-step hold MPC formulation in a cruise control example.

2603.24932 2026-05-08 hep-th gr-qc

The identification between the bulk and boundary conserved quantities

bulk 与 boundary 保守量之间的识别

Gerui Chen, Zien Gao, Xin Lan, Jie-qiang Wu, Hongbao Zhang

AI总结 通过Wald形式主义,研究了非电磁物质场扰动下bulk与boundary保守量的识别,适用于渐近平坦和渐近AdS时空,并展示了测试点粒子的极限情况下的形式。

Comments 5 pages, 1 figure, PRD in press

Journal ref Phys. Rev. D 113, 084024 (2026)

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AI中文摘要

通过Wald形式主义,我们表明,由通用非电磁物质场扰动引起的bulk与boundary保守量的识别不仅适用于渐近平坦的 stationary 空间时,也适用于渐近AdS的 stationary 空间时。我们进一步表明,这种识别在将测试点粒子视为一般物质的极限情况下的形式时,会还原为熟悉的表达形式。

英文摘要

By using Wald formalism, we show that the identification between the bulk and boundary conserved quantities induced by the perturbation of generic non-electromagnetic matter field holds not only on top of the asymptotically flat stationary spacetimes but also on top of the asymptotically AdS stationary ones. We further show that such an identification reduces to the familiar form for the test point particle by viewing it as the limiting case of general matter.

2603.24880 2026-05-08 math.CO cs.CG cs.DM cs.DS

The Four Color Theorem with Linearly Many Reducible Configurations and Near-Linear Time Coloring

四色定理与线性数量的可约配置及近线性时间着色

Yuta Inoue, Ken-ichi Kawarabayashi, Atsuyuki Miyashita, Bojan Mohar, Carsten Thomassen, Mikkel Thorup

AI总结 本文提出了一种近线性时间的四色着色算法,改进了1996年Robertson等人提出的二次时间算法。通过展示平面图中存在线性数量的非接触可约配置或非交叉阻碍循环,增强了四色定理的证明,并为更高曲面的扩展提供了可能。

Comments Source files are available at Github: https://github.com/near-linear-4ct/

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AI中文摘要

我们为平面图提供了一种近线性时间的四色着色算法,改进了Robertson等人1996年提出的二次时间算法。此类算法无法通过已知的四色定理证明方法实现。技术上,我们展示了四色定理的一个重要推广:每个平面三角剖分包含线性数量的非接触可约配置或非交叉阻碍循环(长度不超过5),这些都允许有效的四色着色缩减。已知的四色定理证明仅证明了上述陈述中的单一可约配置或阻碍循环的存在。证明使用基于组合曲率的斥力方法。它识别出局部邻域具有正组合曲率的部分中的可约配置。我们的结果显著加强了已知的四色定理证明,表明我们也可以在大“平坦”部分中找到缩减,这些部分的曲率为零,并且我们可以在给定的平面图中几乎任何地方进行缩减。这还为扩展到更高曲面提供了可能,因为我们可以在任何固定曲面的任何大宽度三角剖分中找到这样的平坦部分。从计算角度来看,旧的证明允许我们应用一个减小了某些加法常数的问题的归纳法。归纳步骤耗时线性,导致总时间二次。通过我们的线性数量的可约配置或阻碍循环,我们可以将问题规模减小一个常数因子。我们的归纳步骤耗时O(n log n),从而得到O(n log n)的总时间。为了高效处理线性数量的可约配置,我们需要它们足够稳健,以便在其他应用中有用。我们所有的可约配置都是所谓的D-可约的。

英文摘要

We give a near-linear time 4-coloring algorithm for planar graphs, improving on the previous quadratic time algorithm by Robertson et al. from 1996. Such an algorithm cannot be achieved by the known proofs of the Four Color Theorem (4CT). Technically speaking, we show the following significant generalization of the 4CT: every planar triangulation contains linearly many pairwise non-touching reducible configurations or pairwise non-crossing obstructing cycles of length at most 5 (which all allow for making effective 4-coloring reductions). The known proofs of the 4CT only show the existence of a single reducible configuration or obstructing cycle in the above statement. The existence is proved using the discharging method based on combinatorial curvature. It identifies reducible configurations in parts where the local neighborhood has positive combinatorial curvature. Our result significantly strengthens the known proofs of 4CT, showing that we can also find reductions in large ``flat" parts where the curvature is zero, and moreover, we can make reductions almost anywhere in a given planar graph. This also opens possibilities for extensions to higher surfaces since we can find such flat parts in any large-width triangulation of any fixed surface. From a computational perspective, the old proofs allowed us to apply induction on a problem that is smaller by some additive constant. The inductive step took linear time, resulting in a quadratic total time. With our linear number of reducible configurations or obstructing cycles, we can reduce the problem size by a constant factor. Our inductive step takes $O(n\log n)$ time, yielding a 4-coloring in $O(n\log n)$ total time. To efficiently handle a linear number of reducible configurations, we need them to be sufficiently robust to be useful in other applications. All our reducible configurations are what is known as D-reducible.

2603.24395 2026-05-08 math-ph math.MP

Particle-Hole Pair Localization on the Fermi Surface and its Impact on the Correlation Energy

费米面附近粒子-空穴对的局域化及其对相关能的影响

Niels Benedikter

AI总结 研究通过对比两种方法,探讨费米面附近粒子-空穴对的局域化对相关能精度的影响,发现集体度自由度描述仅能提供约92%的最优值。

Comments v3: improved presentation & typos fixed; 30 pages; contribution to the Proceedings of the Intensive Period Quantum Mathematics @ Polimi 2025 organized by D. Fermi, M. Moscolari, and A. Olgiati

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AI中文摘要

近年来,已证明近似玻色化如何用于证明相互作用费米子在平均场缩放极限下相关能的随机相位近似。核心在于将费米面附近粒子-空穴激发解释为玻色子。两种主要方法在强调集体自由度(粒子-空穴对在费米面不同区域非局域化)或粒子-空穴对在动量空间中精确局域化方面存在差异。两种方法对常规相互作用势能的精度相同。这提出了问题:非局域化粒子-空穴对的实际影响有多大。在本文中,我们显示仅用少量完全集体玻色自由度的描述仅能提供约92%的最优值。然而,这种简单方法接近最优界是令人瞩目的。

英文摘要

In recent years it has been shown how approximate bosonization can be used to justify the random phase approximation for the correlation energy of interacting fermions in a mean-field scaling limit. At the core is the interpretation of particle-hole excitations close to the Fermi surface at bosons. The main two approaches however differ in emphasizing collective degrees of freedom (particle-hole pairs delocalized over patches on the Fermi surface) or particle-hole pairs exactly localized in momentum space. Both methods lead to equal precision for the correlation energy with regular interaction potentials. This poses the question how big the influence of delocalizing particle-hole pairs really is. In the present note we show that a description with few, completely collective bosonic degrees of freedom only yields an upper bound of about 92% of the optimal value. Nevertheless it is remarkable that such a simple approach comes that close to the optimal bound.

2603.22901 2026-05-08 physics.atom-ph nucl-th

Finite-nuclear-size effect for hydrogenlike ions under high external pressure

氢样离子在高压下的有限核尺寸效应

Dengshan Liu, Huihui Xie, Pengxiang Du, Tianshuai Shang, Jian Li, Jiguang Li, Tomoya Naito

AI总结 研究高压对氢样离子原子能级有限核尺寸修正及电子捕获衰变率的影响,采用高斯分布模拟核电荷分布,通过求解狄拉克方程确定能级和波函数,发现压力显著增强修正和衰变率,改变能级退化性和不同束缚态的修正幅度。

Journal ref Commun. Theor. Phys. 78 (2026) 075301 (7pp)

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AI中文摘要

本文研究了高压对氢样离子原子能级有限核尺寸修正及电子捕获衰变率的影响。离子被建模为处于不可穿透的球形腔内,采用高斯分布表示核电荷分布。对于每个用于模拟外部压力的限制半径,通过动能平衡的广义伪谱方法数值求解狄拉克方程,确定最低束缚态的能级和波函数。与未受限离子相比,压力显著增加有限核尺寸修正和电子捕获衰变率,并在增加限制时表现出平行趋势。压力还移除能级简并性,并改变不同束缚态之间有限核尺寸修正的相对幅度。此外,发现核电荷半径显著影响压力增强的电子捕获衰变率。

英文摘要

The influence of pressure on finite-nuclear-size corrections to atomic energy levels and electron-capture decay rate is investigated in confined hydrogenlike ions. The ions are modeled inside an impenetrable spherical cavity, with a Gaussian distribution used to represent the nuclear charge distribution. For each confinement radius used to simulate external pressure, the energies and wave functions of the lowest-lying bound states are determined by numerically solving the Dirac equation via the kinetically balanced generalized pseudospectral method. In contrast to unconfined ions, both the FNS corrections and electron-capture decay rates increase markedly under pressure and exhibit parallel trends with increasing confinement. Pressure also removes level degeneracies and alters the relative magnitudes of FNS corrections across different bound states. Moreover, the nuclear charge radius is found to significantly affect the pressure-enhanced electron-capture decay rate.

2603.18275 2026-05-08 astro-ph.GA

The Galactic distribution of planetary nebulae with different types of dust

不同类型尘埃的银河分布行星状星云

Diego Hernández-Juárez, Mónica Rodríguez, Miriam Peña

AI总结 研究不同尘埃类型行星状星云在银河中的分布特征,发现混合尘和氧丰富尘星云更靠近银河中心,而碳丰富尘和仅含PAH星云直径更大,推测其演化关系。

Comments 21 pages, 10 figures, 4 tables, accepted for publication in MNRAS

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AI中文摘要

我们通过斯皮策、ISO和IRAS望远镜的红外光谱数据,识别了267个行星状星云中的不同尘埃特征。我们根据尘埃类型对209个天体进行分类:混合尘(MD)、氧丰富尘(ORD)、碳丰富尘(CRD)、仅含多环芳烃(PAHs)的星云(oPAH)以及无特征星云(F)。我们统计研究了不同尘埃类型行星状星云的表面积亮度和直径分布及其在银河中的分布情况。我们发现,MD和ORD星云更靠近银河中心,而CRD和oPAH星云则更远离。各组的银河分布统计上是兼容的,表明它们有相似的前身星。由于oPAH星云平均直径更大且表面积亮度更低,我们推测oPAH星云是演化的CRD星云。另一方面,F星云具有最低的表面积亮度和最大的直径,暗示它们可能包含来自任何初始尘埃类型的演化的星云。在含硅星云中,我们发现只有少数ORD星云在光谱中仅含无定形硅石,其银河心距和银河高度分布表明它们有低质量的前身星。同时,同时含有无定形和结晶硅石的MD星云具有最大的表面积亮度和最小的直径,可能代表最 massive 和金属丰富的前身星云的早期阶段。

英文摘要

We identify different dust features in our compilation of infrared spectra for 267 planetary nebulae (PNe) from the Spitzer, ISO, and IRAS telescopes. We classify 209 objects according to their dust type: mixed dust (MD), oxygen-rich dust (ORD), carbon-rich dust (CRD), PNe with only polycyclic aromatic hydrocarbons (PAHs) in their spectra (oPAH), and featureless (F) PNe. We study statistically the distributions of surface brightness and diameter of PNe with different types of dust as well as their distributions in the Galaxy.We find that both MD and ORD PNe are closer to the Galactic centre than CRD and oPAH PNe, and that the Galactic distributions of each pair of groups are statistically compatible, suggesting that they have similar progenitors. Since oPAH PNe have, on average, larger diameters and lower surface brightness than CRD PNe, we suggest that oPAH PNe are evolved CRD PNe. On the other hand, F PNe have the lowest surface brightness and the largest diameters, suggesting they could contain evolved PNe from any initial type of dust. Among the PNe with silicates, we find that only a few ORD PNe have just amorphous silicates in their spectra, and their distributions of Galactocentric distances and Galactic heights suggest that they had low-mass progenitors. MD PNe with both amorphous and crystalline silicates have the largest surface brightness and the smallest diameters and might be the earliest stages of PNe with the most massive and metal-rich progenitors.

2603.18125 2026-05-08 cond-mat.str-el cond-mat.supr-con

Spin-Charge Groups for Fermions in Fluids and Crystals: General Structures and Physical Consequences

费米子在流体和晶体中的自旋-电荷群:一般结构与物理后果

Arist Zhenyuan Yang, Zheng-Xin Liu

AI总结 本文提出自旋-电荷群(SCGs)作为统一描述费米子系统中自旋、电荷和空间自由度耦合的新框架,探讨其在超流体、超导体等系统中的应用及对新物相分类的贡献。

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AI中文摘要

已知的对称群不足以描述费米子系统中自旋、电荷和空间自由度之间的多种耦合。为此,我们引入自旋-电荷群(SCGs),提供统一的费米子对称性框架。SCGs将自旋和电荷操作作为`内部'对称性,空间和时间操作作为`外部'对称性,并包含其耦合和投影扭量。在推导SCGs的一般群结构后,我们探讨其在具体物理系统中的应用,包括^3He超流体、电荷4e超导体、具有自旋-流的列磁体以及具有共存磁序的超导体。我们显示SCGs可以强制额外的能带简并、陈数和交叉自旋-电荷响应。因此,SCGs提供了一种基于对称性的新途径,用于分类和探索新的物相,即使在强相互作用被包含的情况下。

英文摘要

Known symmetry groups are insufficient to describe the various couplings among spin, charge, and spatial degrees of freedom in fermionic systems. To address this problem, we introduce spin-charge groups (SCGs), which provide a unified framework for fermionic symmetries. SCGs incorporate spin and charge operations as `internal' symmetries, spatial and temporal operations as `external' symmetries, together with their couplings and projective twists. After deriving the general group structure of SCGs, we explore their applications in concrete physical systems, including $^3$He superfluids, charge-4e superconductors, collinear magnets with spin-fluxes, and superconductors with coexisting magnetic orders. We show that SCGs can enforce additional band degeneracies, Chern numbers and cross spin-charge responses. Hence SCGs provide a symmetry-based route toward the classification and exploration of new phases of matter even when strong interactions are included.

2603.18080 2026-05-08 cs.IT math.IT

Growing Alphabets in Canonical Shuffle Experiments: Likelihood-Ratio Laws, Estimation Bounds, and Low-Budget Equivariant Design

在规范洗牌实验中扩展字母表:似然比定律、估计界限与低预算等价设计

Alex Shvets

AI总结 本文研究了在扩展字母表下,有限输出ε₀-LDP d-ary信道的规范一步邻近洗牌实验,探讨了在配对卡方预算下的频率估计和机制设计。通过分析似然比定律,提出了纯LDP端点原理,并建立了全支持障碍族,同时确立了稀释与持久的二元性。

Comments 45 pages, no figures

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AI中文摘要

我们研究了在扩展字母表下,有限输出ε₀-LDP d-ary信道的规范一步邻近洗牌实验,探讨了在配对卡方预算下的频率估计和机制设计。配对似然比定律ν_{ab,d}(在原行下的行比推动)是支配不变量:规范洗牌直方图实验恰好等价于由ν_{ab,d}生成的商多项式实验。字母表增长改进规范洗牌隐私当且仅当最坏配对定律坍缩到δ₁。我们证明了配对卡方的尖锐纯LDP端点原理,构建了全支持障碍族以饱和它,并确立了稀释/持久二元性,同时建立了显式的有限n hockey-stick界限。最坏情况配对预算χ*(W)支配了任意估计器在i.i.d.多项式模型中的Assouad下界。对称化将均匀点Fisher准则减少到排列等价信道。校准GRR并非最优;在低预算范围内,增强GRR在排列等价信道中是最佳的。

英文摘要

We study canonical one-step neighboring shuffle experiments for finite-output epsilon_0-LDP d-ary channels along growing alphabets, with frequency estimation and mechanism design under a pairwise chi-squared budget. The pairwise likelihood-ratio law nu_{ab,d} (pushforward of the row ratio under the null row) is the governing invariant: the canonical shuffled histogram experiment is exactly equivalent to the quotient multinomial experiment generated by nu_{ab,d}. Alphabet growth improves canonical shuffled privacy iff the worst pairwise law collapses to delta_1. We prove a sharp pure-LDP endpoint principle for the pairwise chi-squared, construct full-support obstruction families saturating it, and establish a diluting/persistent dichotomy with explicit finite-n hockey-stick bounds. The worst-case pairwise budget chi_*(W) governs a two-regime Assouad lower bound for arbitrary estimators in the i.i.d. multinomial model. Symmetrization reduces the uniform-point Fisher criterion to permutation-equivariant channels. Calibrated GRR is not optimal; in the low-budget regime, augmented GRR is optimal among permutation-equivariant channels.

2603.17081 2026-05-08 nucl-ex

d(e,e'p) Studies of Exclusive Deuteron Electro-Disintegration

对德引力电离反应的实验研究

W. U. Boeglin, P. Ambrozewicz, K. Aniol, J. Arrington, G. Batigne, P. Bosted, A. Camsonne, L. Coman, G. Chang, J. P. Chen, S. Choi, A. Deur, M. Epstein, J. M. Finn, S. Frullani, C. Furget, F. Garibaldi, O. Gayou, R. Gilman, O. Hansen, D. Hayes, D. W. Higinbotham, W. Hinton, C. E. Hyde, H. Ibrahim, C. W. de Jager, X. Jiang, M. K. Jones, L. J. Kaufman, H. Khanal, A. Klein, S. Kox, L. Kramer, G. Kumbartzki, J. M. Laget, J. LeRose, R. Lindgren, D. J. Margaziotis, P. Markowitz, K. McCormick, Z. Meziani, R. Michaels, B. Milbrath, J. Mitchell, P. Monaghan, M. Moteabbed, P. Moussiegt, R. Nasseripour, K. Paschke, C. Perdrisat, E. Piasetzky, V. Punjabi, I. A. Qattan, G. Quéméner, R. D. Ransome, B. Raue, J. S. Réal, J. Reinhold, B. Reitz, R. Roché, M. Roedelbronn, A. Saha, K. Slifer, P. Solvignon, V. Sulkosky, P. E. Ulmer, E. Voutier, L. B. Weinstein, B. Wojtsekhowski, M. Zeier

AI总结 通过测量不同Q²下的d(e,e'p)截面,研究了缺失动量和中子实验室回转角的影响,证实了最终态相互作用在θ_nq≈70°时最大,CD-Bonn势函数能最佳拟合低FSI数据。

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AI中文摘要

通过测量不同$Q^2$下的$d(e,e'p)$截面,研究了缺失动量和中子实验室回转角的影响,证实了最终态相互作用在$θ_{nq}≈70^\circ$时最大,CD-Bonn势函数能最佳拟合低FSI数据。

英文摘要

The d(e,e'p) cross section was measured at momentum transfers $Q^2 = $ 0.8, 2.1 and 3.5 $(GeV/c)^2$ covering a wide range of proton kinematics at each $Q^2$ setting that made it possible to study this reaction as a function of missing momentum as well as a function of the neutron laboratory recoil angle $θ_{nq}$. Missing momentum distributions were determined for fixed values of $θ_{nq}$ up to missing momenta of 0.65 $GeV/c$. For the two larger momentum transfer settings, the characteristics of the experimental momentum distributions confirm the theoretical prediction that final state interactions (FSI) contribute maximally around a $θ_{nq} \sim 70^\circ$, while for $θ_{nq} < 45^\circ$ FSI are significantly reduced. The data at reduced FSI settings were best reproduced by calculations using the CD-Bonn potential wave functions.

2603.16541 2026-05-08 math.DG math.AP

Liouville theorem on p-biharmonic map from gradient Ricci soliton

p-双调和映射从梯度瑞奇溶子的利乌维尔定理

Xiangzhi Cao

AI总结 本文研究了从梯度瑞奇溶子出发的p-双调和映射,特别是二维香草溶子的性质。

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AI中文摘要

在本文中,我们致力于获得关于从梯度瑞奇溶子出发的p-双调和映射的一些结果,特别是关于二维香草溶子的结果。

英文摘要

In this paper, we are devoted to obtain some results on p-biharmonic map from gradient Ricci soliton, especially on two dimensional cigar soliton.

2603.15626 2026-05-08 nlin.SI hep-th math-ph math.MP

The Bohlin variant of the Eisenhart lift

Bohlin变种的Eisenhart提升

Anton Galajinsky

AI总结 基于Bohlin变换启发,研究了Eisenhart提升的变种,通过嵌入保守动力系统至conformally flat度量的timelike测地线,构造了允许更高秩Killing张量的新型度量。

Comments v2: 13 pages, minor improvements, the version to appear in J. Geom. Phys

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AI中文摘要

受Bohlin变换将平面谐振子与开普勒问题相关联的启发,研究了一种Eisenhart提升的变种,其中具有d个自由度的拉格朗日保守动力系统被嵌入到一个具有洛伦兹签名的(d+2)维时空的conformally flat度量的timelike测地线中。该提升被用于构造新的conformally flat度量,这些度量允许更高秩的Killing张量。

英文摘要

Inspired by the Bohlin transformation relating the planar harmonic oscillator to the Kepler problem, a variant of the Eisenhart lift is studied, in which a Lagrangian conservative dynamical system with d degrees of freedom is embedded into timelike geodesics of a conformally flat metric on a (d+2)-dimensional space-time of the Lorentzian signature. The uplift is used to construct novel examples of conformally flat metrics admitting higher rank Killing tensors.

2603.14926 2026-05-08 cs.MS cs.NA math.NA

Acceleration of multi-component multiple-precision arithmetic with branch-free algorithms and SIMD vectorization

多组件多重精度算术的加速:基于分支-free算法和SIMD向量化

Tomonori Kouya

AI总结 本文通过结合硬件二进制64和二进制32实现多组件算术,利用分支-free算法和SIMD向量化提升三重和四重精度计算效率,并在x86和ARM平台验证线性计算和多项式评估的加速效果。

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AI中文摘要

多重精度浮点分支-free算法可以显著加速通过结合硬件二进制64和二进制32实现的多组件算术,特别是在三重和四重精度计算中。在本研究中,我们通过在x86和ARM CPU平台上的基准测试,量化了通过整合这些算法在线性计算和多项式评估中实现的加速效果。

英文摘要

Multiple-precision floating-point branch-free algorithms can significantly accelerate multi-component arithmetic implemented by combining hardware-based binary64 and binary32, particularly for triple- and quadruple-precision computations. In this study, we achieved benchmark results on x86 and ARM CPU platforms to quantify the accelerations achieved in linear computations and polynomial evaluation by integrating these algorithms.

2603.13712 2026-05-08 quant-ph

Optimal Distillation of Non-Markovianity: Bounds, Multi-Copy Gain, and the Weak-to-Essential Transition

非马尔可夫性最优蒸馏:界限、多副本增益和弱到本质的转变

Gabriel M. Arantes, Barbara Amaral, Nadja K. Bernardes

AI总结 本文提出一种算法,用于确定通过特定量子通道提升量子态可区分性的最大增益,并展示弱非马尔可夫通道可通过蒸馏过程转化为本质非马尔可夫通道,同时分析优化协议的量化特性。

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AI中文摘要

量子通道通常会减少量子态的可区分性,限制信息传输和处理。先前工作引入了一种协议,可在特定量子通道作用后增加态的可区分性。本文系统地展示了如何确定该方法能实现的最大可区分性增益。我们开发了一种算法,用于确定该协议的最佳实现方式,并以简单的方式应用于任意量子通道。通过这种方法,我们证明弱非马尔可夫通道可通过蒸馏过程有效转化为本质非马尔可夫通道。我们进一步分析了优化协议的量化特征,表征了增强最显著的条件。我们的结果提供了一个通用框架,用于评估和优化开放量子系统中的可区分性恢复。

英文摘要

Quantum channels generally reduce the distinguishability of quantum states, limiting information transmission and processing. Previous work introduced a protocol capable of increasing the distinguishability of states after the action of a specific quantum channel. Here we show how to systematically determine the maximal distinguishability gain achievable by this method. We develop an algorithm that identifies the optimal implementation of the protocol and applies to arbitrary quantum channels in a straightforward manner. Using this approach, we demonstrate that a weakly non-Markovian channel can effectively be converted into an essentially non-Markovian one through a distillation-like process. We further analyze the quantitative features of the optimized protocol, characterizing the conditions under which the enhancement is most pronounced. Our results provide a general framework to assess and optimize distinguishability recovery in open quantum systems.

2603.11344 2026-05-08 eess.IV q-bio.QM

Hybrid eTFCE-GRF: Exact Cluster-Size Retrieval with Analytical p-Values for Voxel-Based Morphometry

混合eTFCE-GRF:用于体积基形态学的精确簇大小检索与分析p值

Don Yin, Hao Chen, Takeshi Miki, Enyu Yang

AI总结 本文提出混合eTFCE-GRF方法,结合eTFCE的精确簇大小检索与pTFCE的分析GRF推断,实现无需排列检验的高效体积基形态学分析,验证显示其在控制FDR和提升统计效力方面表现优异。

Comments 25 pages, 7 figures, 3 tables. Submitted to NeuroImage. Open-source package: https://github.com/Don-Yin/pytfce

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AI中文摘要

阈值自由簇增强(TFCE)通过整合阈值下的簇范围来提高体积成像推断,但排列检验使其在大规模数据集上效率低下。概率TFCE(pTFCE)利用分析性高斯随机场(GRF)p值但离散化了阈值网格。精确TFCE(eTFCE)通过并查集数据结构消除离散化但仍需排列检验。本文将eTFCE的并查集用于精确簇大小检索与pTFCE的分析GRF推断相结合。并查集在一次遍历排序体素后构建簇层次结构,使任意阈值下的精确大小查询成为可能;GRF理论则将这些大小转换为分析性p值而无需排列检验。在合成假体(64^3,80受试者)上验证:FWER在名义水平受控(0/200空置拒绝,95%置信区间[0.0%,1.9%]);效力与基线pTFCE相当(Dice≥0.999);平滑误差低于1%;一致性r>0.99。在英国生物银行(N=500)和IXI(N=563)上,显著性图形成参考R pTFCE的严格子集,支持保守的误差控制。在pytfce(pip install pytfce)中实现:基线在约5秒内完成全脑VBM(比R pTFCE快75倍),混合方法在约85秒内完成(比基线快4.6倍)并具有精确簇大小;两者均比排列TFCE快1000倍以上。

英文摘要

Threshold-free cluster enhancement (TFCE) integrates cluster extent across thresholds to improve voxel-wise neuroimaging inference, but permutation testing makes it prohibitively slow for large datasets. Probabilistic TFCE (pTFCE) uses analytical Gaussian random field (GRF) p-values but discretises the threshold grid. Exact TFCE (eTFCE) eliminates discretisation via a union-find data structure but still requires permutations. We combine eTFCE's union-find for exact cluster-size retrieval with pTFCE's analytical GRF inference. The union-find builds the cluster hierarchy in one pass over sorted voxels and enables exact size queries at any threshold; GRF theory then converts these sizes to analytical p-values without permutations. Validation on synthetic phantoms (64^3, 80 subjects): FWER controlled at nominal level (0/200 null rejections, 95% CI [0.0%, 1.9%]); power matches baseline pTFCE (Dice >= 0.999); smoothness error below 1%; concordance r > 0.99. On UK Biobank (N=500) and IXI (N=563), significance maps form strict subsets of reference R pTFCE, which supports conservative error control. Implemented in pytfce (pip install pytfce): baseline completes whole-brain VBM in ~5s (75x faster than R pTFCE), hybrid in ~85s (4.6x faster) with exact cluster sizes; both >1000x faster than permutation TFCE.

2603.11196 2026-05-08 cs.CR math.NT

Primitive-Root Ratio over Prime Fields: A Shifted-Prime Distribution of Hausdorff Dimension Zero and Implications for PRIM-LWE

素数域上的原根比:一种移位素数分布,具有Hausdorff维数为零的特性及其对PRIM-LWE的影响

Vipin Singh Sehrawat

AI总结 研究素数域上矩阵行列式为原根的比例分布,证明其极限分布具有Hausdorff维数为零的特性,并探讨其对PRIM-LWE在密码学中的影响。

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AI中文摘要

对于素数p,令c(p)表示n×n矩阵在F_p上的极限分数,其行列式为p模的原根。c(p)是欧拉函数比φ(p-1)/(p-1)的自然乘法变形,并继承其在素数上的分布行为。通过移位素数Erdős-Wintner-Hildebrand框架证明了极限分布的存在性和连续性。证明了无条件下,inf_p c(p)=0,且最小值的阶为min_{p≤x}c(p)≈1/log log x;倒数满足limsup_{p→∞, p为素数}1/(c(p)log log p)=e^γ,且无更小常数能替代。通过结合Erdős的论证与Jessen-Wintner纯类型二分法,证明极限分布是纯奇异的,并进一步加强为Hausdorff维数为零。分布具有完整拓扑支持[0,1/2],并允许以奇素数为索引的伯努利积表示。矩由收敛的欧拉乘积给出,且 Mellin 变换 E[X^s] 扩展为s的整个函数,在Re(s)>0时不为零。在右端点附近,1-G(1/2-ε)≈κ/log(1/ε)(其中κ为显式常数)。1/c(p)等于从学习误差(LWE)到PRIM-LWE的降维过程中,基于格密码学的拒绝采样开销的维度均匀期望值。显式界提供了当前NIST后量子标准和代表性NTT友好模数中所有素数的明确开销估计。

英文摘要

For a prime $p$, let $c(p)$ denote the limiting fraction of $n\times n$ matrices over $\mathbb{F}_p$ whose determinant is a primitive root modulo $p$. The quantity $c(p)$ is a natural multiplicative deformation of the totient ratio $φ(p-1)/(p-1)$ and inherits its distributional behaviour over the primes. Existence and continuity of the limiting law follow from the shifted-prime Erdős--Wintner--Hildebrand framework. We prove the following new results: unconditionally, $\inf_p c(p)=0$ and the sharp order is $\min_{p\le x}c(p)\asymp 1/\log\log x$; the reciprocal satisfies $\limsup_{p\to\infty, \, p\text{ prime}} 1/(c(p)\log\log p)=e^γ$, and no smaller constant suffices. We give a complete proof, combining an adaptation of Erdős's argument with the Jessen--Wintner pure-type dichotomy, that the limiting distribution is purely singular, and strengthen this to $\dim_H(μ_G)=0$, i.e. the limiting measure is carried by a Borel set of Hausdorff dimension zero. The distribution has full topological support $[0,\tfrac12]$ and admits a Bernoulli-product representation indexed by the odd primes. The moments are given by convergent Euler products, and the Mellin transform $\mathbb{E}[X^s]$ extends to an entire function of $s$, non-vanishing on $\operatorname{Re}(s)>0$. Near the right endpoint, $1-G(\tfrac12-\varepsilon)\simκ/\log(1/\varepsilon)$ with an explicit constant $κ$. The quantity $1/c(p)$ equals the dimension-uniform expected rejection-sampling overhead in the reduction from learning with errors (LWE) to PRIM-LWE in lattice-based cryptography. The explicit bounds yield concrete overhead estimates for all primes appearing in current NIST post-quantum standards and representative NTT-friendly moduli.

2603.10798 2026-05-08 cond-mat.mtrl-sci cond-mat.mes-hall

Engineering Magnetic Anisotropy in Permalloy Films via Atomic Force Nanolithography

通过原子力纳米光刻工程化永磁合金薄膜的磁各向异性

Abhishek Naik, Cyril Delforge, Nicolas Lejeune, Daniel Stoffels, Joris Van de Vondel, Kristiaan Temst, Alejandro V. Silhanek, Emile Fourneau

AI总结 该研究利用原子力纳米光刻技术在永磁合金薄膜中精确调控磁各向异性,通过微米尺度沟槽阵列诱导平面单轴各向异性,展示出可控的磁性硬性调制及磁域结构定向设计。

Comments 12 pages, 6 figures (Supplementary Material available upon request)

Journal ref Small (2026): e14880

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AI中文摘要

原子力纳米光刻提供了一种精确塑造磁性薄层的方法,使在软铁磁体中可控地在微米尺度上工程化磁各向异性。我们证明在永磁合金(Ni80Fe20)薄膜中雕刻的纳米级沟槽阵列诱导出稳定的平面单轴各向异性,易轴沿沟槽方向对齐。各向异性场随着沟槽周期减小和雕刻深度增加而增强,提供在单次制备步骤中连续调节磁性硬性的能力。人工雕刻的微结构进一步允许磁域配置和磁域壁轨迹沿预定路径定向,例如通过创建棋盘状的磁性景观来展示。由于其适用于多种铁磁材料和任意凹槽几何形状,这种方法提供了一个多功能平台来定制平面磁各向异性。具体应用包括磁子器件和各向异性磁阻传感器的设计。

英文摘要

Atomic force nanolithography provides a precise method for sculpting magnetic thin films, enabling controlled engineering of magnetic anisotropy in soft ferromagnets at the microscale. We demonstrate that nanoscale groove arrays patterned into permalloy (Ni80Fe20) films induce a robust in-plane uniaxial anisotropy, with the easy axis aligned along the groove direction. The anisotropy field is shown to increase with decreasing groove period and increasing engraving depth, offering continuous tunability of magnetic hardness within a single fabrication step. Artificially engraved microstructures further allow domain configurations and domain-wall trajectories to be directed along predefined pathways, exemplified by the creation of a chessboard-like magnetic landscape. Owing to its adaptability to diverse ferromagnetic materials and arbitrary corrugation geometries, this approach provides a versatile platform for tailoring in-plane magnetic anisotropy. Concrete applications are demonstrated in the design of magnonic elements and anisotropic magnetoresistance sensors.

2603.09459 2026-05-08 math.DG math.FA math.MG

Nonlinear Lebesgue spaces: Curves and geometry

非线性勒贝格空间:曲线与几何

Guillaume Sérieys

AI总结 本文研究非线性勒贝格空间的几何与分析性质,通过非线性弗比尼-勒贝格定理的推广,定义了绝对连续曲线的速度,并描述了空间的长度结构和阿莱克山德罗夫曲率界。

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AI中文摘要

本文是作者与合作者系列研究的第二篇,致力于研究非线性勒贝格空间的几何与分析性质,即映射值域为任意度量空间的L^p空间。本文正式描述了这些空间的几何性质——其长度结构、阿莱克山德罗夫曲率的界以及在缺乏微分结构的情况下绝对连续曲线的速度定义。为了获得这种点描述,我们首先证明了一个非线性弗比尼-勒贝格定理的非线性类比,这导致了非线性勒贝格空间中L^p曲线被识别为映射到L^p曲线空间的映射。这种识别使得绝对连续曲线的类似识别成为可能,从而推导出非线性勒贝格空间几何性质的点描述。

英文摘要

This paper is the second in a series by the author and collaborators devoted to the study of geometric and analytic properties of nonlinear Lebesgue spaces, that is, L^p spaces of mappings taking values in arbitrary metric spaces. The present article formalizes the pointwise description of their geometric properties -- their length structure, bounds on their Alexandrov curvature as well as the definition of a speed for absolutely continuous curves despite the lack of differential structure. To obtain this pointwise description, we first prove a nonlinear analogue of the Fubini--Lebesgue theorem, which yields an identification of L^p curves in nonlinear Lebesgue spaces to mappings taking values in the space of L^p curves. This identification of L^p curves then enables a similar identification for absolutely continuous curves, from which the pointwise description of the geometric properties of nonlinear Lebesgue spaces follows.

2603.06528 2026-05-08 math.PR math.CV

Circle packing and Riemann uniformization of random planar maps in an ergodic scale-free environment

随机平面图的圆打包与黎曼统一化在ergodic自相似环境中的研究

Nina Holden, Pu Yu

AI总结 研究证明,在满足特定条件时,随机平面图在大规模上接近其圆打包和黎曼统一化嵌入,扩展了随机游走不变性原理的应用。

Comments 55 pages, 9 figures; Extended from triangulations to general planar maps and removed almost planarity condition from the previous version

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AI中文摘要

我们证明,在满足适当矩条件和连通性条件时,嵌入的无限平面图在ergodic自相似环境中在大尺度上接近其圆打包和黎曼统一化嵌入。ergodic自相似环境最初由Gwynne, Miller和Sheffield(2018)在随机游走不变性原理的背景下考虑,并自然出现在随机平面图和利乌维尔量子引力的研究中。

英文摘要

We prove that embedded infinite planar maps in ergodic scale-free environments are close to their circle packing and Riemann uniformization embedding on a large scale, as long as suitable moment and connectivity conditions are satisfied. Ergodic scale-free environments were earlier considered by Gwynne, Miller and Sheffield (2018) in the context of the invariance principles for random walk, and they arise naturally in the study of random planar maps and Liouville quantum gravity.

2603.04801 2026-05-08 cs.CR cs.ET

ShieldBypass: On the Persistence of Impedance Leakage Beyond EM Shielding

ShieldBypass:超越电磁屏蔽的阻抗泄漏持久性研究

Md Sadik Awal, Md Tauhidur Rahman

AI总结 研究在电磁屏蔽抑制辐射发射后,阻抗调制背散射是否仍能被观测,通过实验表明状态依赖的阻抗变化在屏蔽主衰减带外仍可被检测,推动硬件安全评估中考虑主动阻抗探测。

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AI中文摘要

电磁(EM)屏蔽广泛用于抑制辐射发射并限制被动EM侧信道泄漏。然而,屏蔽无法解决主动探测问题,即攻击者注入外部射频(RF)信号并观测设备的反射响应。本文研究在抑制辐射发射后,这种由阻抗调制的背散射是否仍持续存在。通过注入受控的RF信号并分析反射,我们证明在屏蔽的主要衰减带外,状态依赖的阻抗变化仍可被观测。使用在FPGA和微控制器原型上实现的处理器,并在三种行业标准屏蔽下评估工作负载配置,我们发现被动EM测量在屏蔽下失去判别能力,而背散射响应仍可分离。这些结果表明,即使在屏蔽系统中,主动RF探测仍能暴露执行依赖行为,推动在硬件安全评估流程中考虑主动阻抗探测的必要性。

英文摘要

Electromagnetic (EM) shielding is widely used to suppress radiated emissions and limit passive EM side-channel leakage. However, shielding does not address active probing, where an adversary injects external radio-frequency (RF) signals and observes the device's reflective response. This work studies whether such impedance-modulated backscattering persists when radiated emissions are suppressed by shielding. By injecting controlled RF signals and analyzing the reflections, we demonstrate that state-dependent impedance variations remain observable at frequencies outside the shields' primary attenuation band. Using processors implemented on FPGA and microcontroller prototypes, and evaluating workload profiles under three industry-standard shields, we find that passive EM measurements lose discriminative power under shielding, while backscattering responses remain separable. These results indicate that active RF probing can expose execution-dependent behavior even in shielded systems, motivating the need to consider active impedance-based probing within hardware security evaluation flows.