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2604.26452 2026-06-05 hep-th gr-qc math-ph math.MP

Integrable Deformations of the Breitenlohner-Maison Model from 4d Chern-Simons Theory

从4维Chern-Simons理论出发的Breitenlohner-Maison模型的可积分变形

Meer Ashwinkumar, Matthias Blau

AI总结 本文基于4维Chern-Simons理论,研究了Breitenlohner-Maison(sigma)模型的可积分变形及其高阶推广,通过改变边界条件和作用量,得到与齐次和非齐次经典Yang-Baxter方程相关的BM模型变形。

Comments 24 pages. Further clarifications. Version accepted for publication in JHEP

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AI中文摘要

我们利用4维Chern-Simons理论的框架,推导了描述4维广义相对论静态、轴对称部分的2维Breitenlohner-Maison(BM)sigma模型的可积分变形,以及其高阶推广。特别地,我们考虑了4维Cole-Weck模型的边界条件和作用量的变形,这些变形导致与齐次和非齐次经典Yang-Baxter方程相关的BM模型的变形。

英文摘要

We derive integrable deformations of the 2d Breitenlohner-Maison (BM) sigma model that describes the stationary, axisymmetric sector of 4d general relativity, as well as higher-rank generalisations thereof, using the framework of 4d Chern-Simons theory. In particular, we consider deformations of the boundary conditions and action of the 4d Cole-Weck model, which lead to deformations of the BM model associated with solutions to the homogeneous and inhomogeneous classical Yang-Baxter equations respectively.

2604.26429 2026-06-05 math.NT math.CO

Solution to the Erdos problem on distinct residues of factorials

Erdos问题的解:阶乘的不同剩余

Vyacheslav M. Abramov

AI总结 本文用初等方法证明,对于大于5的素数p,2!, 3!, ..., (p-1)!模p的剩余不可能全部不同。

Comments 9 pages. In general, the proof is the same as in the previous version. However, I was needed one more revision to fix some typos and shorten the paper again. Some explanations are clarified more

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AI中文摘要

Paul Erdos提出了以下问题:是否存在一个素数$p>5$,使得$2!$,$3!$,\ldots,$(p-1)!$模$p$的剩余全部不同。在这篇短文中,我们以初等方式给出了该问题的否定答案。

英文摘要

Paul Erdos posed the following question: Is there a prime number $p>5$ such that the residues of $2!$, $3!$,\ldots, $(p-1)!$ modulo $p$ all are distinct. In this short note, we give the negative answer on this question in an elementary way.

2604.20498 2026-06-05 hep-th

Anisotropic drag force in finite-density QGP from charged rotating 5D black holes

有限密度QGP中带电旋转五维黑洞的各向异性阻力力

Sergei G. Ovchinnikov

AI总结 研究有限密度和各向异性全息等离子体中重夸克所受的阻力力,通过五维最小规范超引力CCLP黑洞的对偶模型,分析带电旋转参数对阻力力各向异性的影响,并计算其有限密度极限下的修正自由能移位。

Comments 28 pages, 3 figures

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AI中文摘要

我们研究了具有旋转各向异性及有限密度的全息等离子体中重夸克所受的阻力力。本体的对偶是五维最小规范超引力的CCLP黑洞,其特征由两个独立的旋转参数和电荷决定。在中性Kerr-AdS极限下,我们利用主Killing弦获得任意旋转参数下的精确阻力力,该力纯切向但通常各向异性,仅在等自旋部分退化为粘性形式。然后我们分析带电CCLP背景中静止弦在慢旋转极限下的扰动行为。洛伦兹世界片的正则性分析确定了角积分常数,从而得到有限修正的横向阻力力,并具有平滑的Kerr-AdS极限。我们还证明,在等自旋部分,世界片正则性选择了一个唯一的共旋转平衡夸克,并计算其修正自由能移位。

英文摘要

We study the drag force acting on a heavy quark in a holographic plasma with rotational anisotropy and finite density. The bulk dual is the CCLP black hole of five-dimensional minimal gauged supergravity, characterised by two independent rotation parameters and electric charge. In the neutral Kerr--AdS limit, we use the principal Killing string to obtain an exact drag force for arbitrary rotation parameters. The resulting force is purely tangential but generically anisotropic, reducing to the viscous form only in the equal-spin sector. We then analyse stationary strings in the charged CCLP background perturbatively in the slow-rotation regime. A regularity analysis of the Lorentzian worldsheet fixes the angular integration constants that would otherwise remain ambiguous, yielding a finite renormalised transverse drag force with a smooth Kerr--AdS limit. We also show that, in the equal-spin sector, worldsheet regularity selects a unique co-rotating equilibrium quark and compute its renormalised free-energy shift.

2503.23047 2026-06-05 astro-ph.HE

Distinct Signatures of the Nature of Phase Transition in Binary Neutron Star Mergers

二元中子星并合中相变性质的distinct signatures

Sagnik Chatterjee, Shamim Haque, Kamal Krishna Nath, Rana Nandi, Ritam Mallick

AI总结 本文研究二元中子星并合中相变性质对引力波信号的影响,通过建立多参数方程状态家族,分析混合相态对并合动力学的直接冲击,并发现相变性质在谱图中留下特定印记,建立了Δp与即时坍缩阈值质量之间的首次关联。

Comments 18 pages, 19 figures and 3 Tables. Accepted in Phys. Rev. D

Journal ref Phys. Rev. D 113, 123009 (2026)

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AI中文摘要

二元中子星并合为理解中子星物质性质提供了关键见解。我们提出了可能在引力波信号中留下的相变性质的印记。我们的研究采用了一种基于多项式方法构建的单参数方程状态家族,利用控制参数Δp调查了从最大构造到吉布斯构造的强子-夸克相变特征。这使我们能够探讨混合相的范围,并分析其对并合动力学的直接影响。并合后引力波发射揭示了谱图和功率谱密度中的特定印记,成为具有混合相的方程状态的明显特征。我们发现功率谱密度中出现额外峰,这些峰仅由并合后残余经历相变产生。此外,相变的性质在谱图中留下特定印记,导致引力波分析中出现双重特征。此外,我们建立了Δp与即时坍缩阈值质量之间的首次关联。我们的分析表明,如果GW170817形成了长寿命残余或经历了延迟坍缩为黑洞,则需要Δp ≲ 0.04。

英文摘要

Binary neutron-star mergers offer crucial insights into the matter properties of neutron stars. We present the possible imprints in the gravitational wave signal from the nature of phase transition from such events. Our study employs a one-parameter family of equation of states built using a polytropic approach with a control parameter $Δp$ surveying the features of hadron-quark phase transition, from Maxwell construction to the Gibbs construction. It allows us to explore the extent of mixed phases and analyse their direct impact on merger dynamics. Post-merger gravitational wave emissions reveal the expression of specific signatures in the spectrogram and power spectral density, serving as a distinct signature of equations of state with mixed phases. We found additional peaks in power spectral density that are exclusively generated from the post-merger remnant experiencing a phase transition. Additionally, the nature of phase transition leaves specific imprints on the spectrogram, leading to a two-folded signature from gravitational wave analysis. Furthermore, we establish the first correlation between $Δp$ and the threshold mass for prompt collapse. Our analysis shows that $Δp \lesssim 0.04$ is required if GW170817 formed a long-lived remnant or has experienced a delayed collapse into a black hole.

2604.24069 2026-06-05 physics.flu-dyn

Beyond Stokes drift -- Lagrangian transport in evolving gravity waves

超越斯托克斯漂移——演化的重力波中的拉格朗日输运

Tatsuo Izawa, Giulio Foggi Rota, Alessandro Chiarini, Marco Edoardo Rosti

AI总结 本文研究了自由衰减波中的拉格朗日输运,通过高分辨率两相模拟和扰动分析模型,揭示了波幅扩展中一阶和二阶修正对经典拉格朗日漂移的影响,并探讨了粘性和惯性平衡下的净垂直输运对粒子轨迹和各向异性混合的影响。

Comments 7+8 pages, 6+5 figures

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AI中文摘要

在空气-水界面处的有限振幅重力波会引起净流体和粒子输运,称为斯托克斯漂移。尽管这一机制在稳态波中已被充分理解,但在非稳态、演变条件下输运特性仍不明确。本文通过高分辨率两相模拟和扰动分析模型,研究了自由衰减波中的拉格朗日输运。波衰减修改了经典拉格朗日漂移,引入了波幅展开中的一阶和二阶修正,并产生由惯性和粘性平衡支配的净垂直输运。这些效应改变了粒子轨迹并增强了各向异性混合,对解释现场观测和建模表面输运过程具有影响。

英文摘要

Finite-amplitude gravity waves at the air-water interface induce net fluid and particle transport, known as Stokes drift. While this mechanism is well understood for steady waves, transport under unsteady, evolving conditions remains poorly characterized. Here, we investigate Lagrangian transport in freely decaying waves using high-resolution two-phase simulations and a perturbative analytical model. Wave decay modifies the classical Lagrangian drift by introducing both first- and second-order corrections in the wave amplitude expansion, and generates a net vertical transport, governed by the balance between inertia and viscosity. These effects alter particle trajectories and enhance anisotropic mixing, with implications for interpreting field observations and modelling surface transport processes.

2507.09552 2026-06-05 astro-ph.CO

Probing the scalar-induced gravitational waves with the Five-hundred-meter Aperture Spherical radio Telescope and the Square Kilometer Array

利用五百米口径球面射电望远镜和平方公里阵列探测标量诱导引力波

Jun Li, Guanghai Guo, Pengfei Yan

AI总结 本文利用FAST和SKA提供的上界或下界随机引力波背景数据,结合宇宙微波背景和宇宙学声学振荡数据,约束标量诱导引力波,并通过两种场景预测其参数约束。

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AI中文摘要

引力波天文学提供了一个直接观测早期宇宙中由标量场诱导的引力波的有希望的机会。实验,包括地面干涉仪如LIGO和Virgo,以及脉冲星计时阵列如FAST和SKA,都有潜力显著提高对这些引力波的灵敏度。在本文中,我们结合宇宙微波背景和宇宙学声学振荡数据集,与FAST或SKA提供的随机引力波背景的上界或下界相结合,以约束标量诱导引力波。为了提供全面的预测,我们考虑两种场景:一种是FAST或SKA未检测到标量诱导引力波,从而设置分数能量密度的上限;另一种是成功检测到这些波,从而建立下限。在ΛCDM+r模型中,标量功率谱的标量谱指数在标量诱导引力波以光速传播的上限场景中被约束为n_s=0.9598^{+0.0013}_{-0.0009},来自CMB+BAO+SKA数据集的组合。在下限场景中,约束变为n_s=0.9697±0.0033。与CMB+BAO数据集的组合约束相比,上限场景中的标量谱指数n_s表现出显著变化,这可能成为检测标量诱导引力波的指标。在ΛCDM+α_s+r模型和ΛCDM+α_s+β_s+r模型中,标量谱指数的运行α_s和运行的运行β_s也显示出显著变化,表明潜在的指标。数值结果清楚地展示了FAST或SKA提供的上界和下界的影响。

英文摘要

Gravitational wave astronomy presents a promising opportunity to directly observe scalar-induced gravitational waves originating from the early universe. Experiments, including ground-based interferometers like LIGO and Virgo, and the Pulsar Timing Array, such as FAST and SKA, are poised to significantly enhance sensitivity to these gravitational waves. In this paper, we combined Cosmic Microwave Background and Baryon Acoustic Oscillation datasets with upper or lower limits of the stochastic gravitational wave background provided by FAST or SKA, to constrain scalar-induced gravitational waves. To provide a comprehensive forecast, we consider two scenarios at a frequency: one where FAST or SKA does not detect scalar-induced gravitational waves, thereby setting an upper limit on the fractional energy density; and another where these waves are detected successfully, thus establishing a lower limit. In the $Λ$CDM+$r$ model, the scalar spectral index of the power-law power spectrum is constrained to $n_s=0.9598^{+0.0013}_{-0.0009}$ from the combinations of CMB+BAO+SKA datasets in the upper limit scenario where scalar-induced gravitational waves propagate at the speed of light. The constraint shifts to $n_s = 0.9697\pm{0.0033}$ in the lower limit scenario. Comparing with the constraint from the combinations of CMB+BAO datasets, the scalar spectral index $n_s$ in the upper limit scenario exhibits significant changes, which could serve as an indicator for detecting scalar-induced gravitational waves. In the $Λ$CDM+$α_s$+$r$ model and $Λ$CDM+$α_s$+$β_s$+$r$ model, the running of the scalar spectral index $α_s$ and the running of the running $β_s$ also show notable variations, suggesting potential indicators. The numerical findings clearly demonstrate the impact of the upper and lower limits provided by FAST or SKA.

2604.24591 2026-06-05 nucl-ex

Quenching of the proton $\pi0p_{3/2}$-$\pi0p_{1/2}$ spin-orbit splitting in $^{20}$O and the effect of the tensor force

氧-20中质子π0p_{3/2}-π0p_{1/2}自旋-轨道分裂的淬灭及张力力的影响

J. Lois-Fuentes, B. Fernández-Domínguez, T. Roger, F. Delaunay, M. Lozano-González, O. Sorlin, T. Otsuka, T. Suzuki, N. L. Achouri, M. Caamaño, C. Cabo, L. Cáceres, A. Candiello, A. Cassisa, A. Ceulemans, F. Cresto, Q. Delignac, J. A. Dueñas, D. Fernández-Fernández, S. Fracassetti, J. Giovinazzo, S. Grévy, G. F. Grinyer, V. Guimarães, O. Kamalou, T. Kurtukian-Nieto, M. B. Latif, B. Mauss, C. Nicolle, A. Ortega-Moral, J. Pancin, J. Piot, O. Poleshchuk, R. Raabe, D. Ramos, D. Regueira-Castro, A. M. Sánchez-Benítez, J. C. Thomas, M. Vandebrouck, J. C. Zamora

AI总结 研究通过ACTAR TPC装置首次直接测量了氧-20核中的Z=6壳隙,发现质子自旋-轨道分裂减小,与张力力效应一致,与其它研究中观察到的较大Z=6壳隙相矛盾。

Journal ref Phys. Rev. Lett. 136 212501 (2026)

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AI中文摘要

我们首次直接测量了富中子氧-20核中的Z=6壳隙。利用GANIL的ACTAR TPC装置研究了2H(20O,3He)19N单质子移除转移反应。ACTAR TPC的使用使得在保持分辨率的情况下测量低截面质子移除反应成为可能。在19N中鉴定出八个l=1的p空态,分别占0p3/2和0p1/2单粒子轨道总强度的86%和72%。所测态的能量和能谱因子允许确定氧-20中的质子自旋-轨道分裂0p3/2 - 0p1/2。Z=6壳隙被确定为5.30(14) MeV。这些发现表明在sd价轨道中加入中子时Z=6壳隙减小,与由最先进的壳层模型相互作用SFO-tls预测的张力力效应一致,但与其它研究中观察到的较大Z=6壳隙相矛盾。

英文摘要

We present the first direct measurement of the Z=6 shell gap in the neutron-rich 20O nucleus. The one-proton removal transfer reaction 2H(20O,3He)19N has been studied using the ACTAR TPC setup at GANIL. The use of ACTAR TPC enabled the measurement of low-cross section proton-removal reactions while preserving resolution. Eight p-hole states with l=1 were identified in 19N accounting for total strengths of 86% and 72% of the 0p3/2 and 0p1/2 single-particle orbitals, respectively. The energies and spectroscopic factors of the measured states allowed to determine the proton spin-orbit splitting 0p3/2 - 0p1/2 in 20O. The Z=6 shell gap has been established to be 5.30(14) MeV. These findings indicate a reduction of the Z=6 shell gap while adding neutrons to the sd-valence orbitals, consistent with the effects of the tensor force predicted by state-of-the-art shell model interaction SFO-tls while at variance with the emergence of a large Z=6 gap observed in other studies.

2509.07833 2026-06-05 physics.atom-ph

A framework for continuous superradiant laser operation via sequential transport of atoms

通过原子顺序传输实现连续超辐射激光操作的框架

Jana El Badawi, Marion Delehaye, Bruno Bellomo

AI总结 本文研究了通过顺序传输原子实现连续超辐射激光的操作框架,通过分析原子与谐振腔的耦合,发现激光在特定参数空间内可达到十皮瓦功率和子毫赫兹线宽,并探讨了不均匀频率展宽和原子-谐振腔耦合变化对超辐射发射的影响,发现其鲁棒性得益于原子偶极子的同步效应。

Comments 30 pages, 13 figures. Updated version close to the published one, with funding information

Journal ref C. R. Phys. 27, 191 (2026)

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AI中文摘要

我们对支持在FEMTO-ST实现实验实现的连续超辐射激光进行了理论研究,使用两个依次发射的${}^{171}\mathrm{Yb}$原子团,这些原子团耦合到相同的法布里-珀罗腔。采用开放量子系统方法,我们确定了最简单情况下激光达到十皮瓦功率和子毫赫兹线宽的参数空间。研究不均匀频率展宽和原子-谐振腔耦合变化对超辐射发射的影响,发现其鲁棒性得益于原子偶极子的同步效应。随后我们考虑了双站点配置,其中每个站点的原子均耦合到腔并具有相同的调制,但两个团的耦合和调制不同。我们发现对于平衡和不平衡的原子数,同步在特定参数空间内导致单一窄谱线,其中心频率遵循加权平均频率。这一结果表明,通过顺序加载可以实现连续超辐射发射,只要两个团的相对频率能控制到所需的目标稳定性水平。

英文摘要

We perform a theoretical study of a continuous superradiant laser supporting its experimental realization at FEMTO-ST using two sequentially-emitting ensembles of ${}^{171}\mathrm{Yb}$ atoms coupled to the same Fabry-Perot cavity. Using an open quantum system approach, we identify for the simplest case the parameter space where the laser reaches tens of picowatts of power with a sub-millihertz linewidth. Studying the impact of inhomogeneous frequency broadening and variations in atom-cavity coupling on the superradiant emission, we find the laser properties robust with respect to such perturbations, also thanks to the occurrence of synchronization of the atomic dipoles. We then consider a two-site configuration, in which atoms in each site are equally coupled to the cavity and have equal detunings, with different values for the two ensembles. We find for balanced and imbalanced atom numbers that synchronization leads in a certain parameter space to a single narrow spectral line whose central frequency follows the weighted average frequency. This result indicates that sequential loading can enable continuous superradiant emission for metrological applications, provided that the relative frequencies of the two ensembles are controlled to the level required by the target stability.

2604.24027 2026-06-05 cs.DC

KubePACS: Kubernetes Cluster Using Performant, Highly Available, and Cost Efficient Spot Instances

KubePACS: 一种使用高性能、高可用性和成本高效的Spot实例的Kubernetes集群

Taeyoon Kim, Kyumin Kim, Enrique Molina-Giménez, Pedro García-López, Kyungyong Lee

AI总结 本文提出KubePACS,一种Kubernetes原生的Spot实例 provisioning系统,通过多目标优化问题优化节点池,同时保证高可用性,从而在成本和性能之间取得平衡。

Comments Accepted to the 27th ACM International Middleware Conference (Middleware 2026)

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AI中文摘要

云用户希望通过选择最适合其工作负载的实例类型来在最小化成本的同时最大化性能。为了降低成本,Spot实例因其与按需定价相比的大幅折扣而被广泛采用。然而,它们的使用引入了可靠性风险,由于可能的中断,现有研究主要从成本或可用性角度单独缓解这种权衡。尽管实例类型在硬件能力上存在多样性,当前的 provisioning系统往往忽视性能变化,仅根据最小资源需求选择节点。在本文中,我们提出了KubePACS,一种Kubernetes原生的Spot实例 provisioning系统,构建了在成本和性能方面都优化的节点池,同时保证高可用性。KubePACS将节点选择过程公式化为一个多目标优化问题,结合实时数据,如Spot价格、性能基准和可用性评分,包括多节点Spot Placement Score(SPS)。它通过整数线性规划(ILP)方法,结合黄金分割搜索(GSS)算法高效地解决这个问题。通过与Karpenter节点自动扩展器集成,KubePACS在标准 provisioning工作流中联合优化实例类型选择和节点扩展决策。KubePACS还采用了一种新的启发式方法,通过将性能指标扩展到专用实例来支持工作负载特定的偏好。通过在合成和实际工作负载上的广泛评估,KubePACS在平均上比Karpenter、SpotVerse和SpotKube等最先进的解决方案高出55.09%至81.06%的每美元性能。

英文摘要

Cloud users aim to minimize cost while maximizing performance by selecting the most suitable instance types for their workloads. To reduce expenses, spot instances have been widely adopted due to their steep discounts compared to on-demand pricing. However, their use introduces reliability risks due to potential interruptions, and existing research has primarily focused on mitigating this trade-off from a cost or availability perspective alone. Despite the diversity in hardware capabilities among instance types, current provisioning systems tend to ignore performance variation, selecting nodes solely based on minimum resource requirements. In this paper, we present KubePACS, a Kubernetes-native spot instance provisioning system that constructs node pools optimized for both cost and performance while guaranteeing high availability. KubePACS formulates the node selection process as a multi-objective optimization problem, incorporating real-time data such as spot prices, performance benchmarks, and availability scores, including the multi-node Spot Placement Score (SPS). It solves this problem efficiently using an Integer Linear Programming (ILP) approach guided by the Golden Section Search (GSS) algorithm to find the optimal configuration. By integrating with the Karpenter node autoscaler, KubePACS jointly optimizes instance-type selection and node scaling decisions within a standard provisioning workflow. KubePACS also adopts a novel heuristic to support workload-specific preferences by scaling performance metrics for specialized instances. Through extensive evaluation across synthetic and real-world workloads, KubePACS demonstrates on average 55.09% and up to 81.06% higher performance per dollar over state-of-the-art solutions such as Karpenter, SpotVerse, and SpotKube, which only reference the spot instance prices and limited availability data.

2604.23503 2026-06-05 astro-ph.HE

Hyperaccreting Neutron Stars inside Massive Envelopes: The Implausibility of Thorne-Żytkow Objects

超临界吸积的中子星内部巨量包层:Thorne-Żytkow对象的不可行性

Patrick Chi-Kit Cheong, David Radice, Christopher L. Fryer

AI总结 研究超临界吸积中子星在巨量包层中的演化,探讨Thorne-Żytkow对象形成的可能性,发现中子星无法形成超新星爆炸,且会迅速超过Tolman-Oppenheimer-Volkoff质量极限,最终导致黑洞形成。

Comments Accepted version

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AI中文摘要

中子星(NS)嵌入巨量恒星包层的演化是二元恒星演化的关键阶段,可能形成Thorne-Żytkow对象(TŻOs)或灾难性坍缩。我们首次进行了完全耦合的广义相对论流体动力学(GRHD)模拟,同时包含灰色两时刻(M1)中微子传输和α链核反应网络。通过研究四个不同的前身演化阶段,我们解析了强烈中微子冷却、多维流体动力学和核反馈之间的复杂相互作用。我们的结果表明,虽然剧烈对流在冲击波后区域被触发,但全局能量预算主要由中微子冷却主导,有效平衡了吸积功率。关键的是,尽管我们的M1传输方案捕获了中微子吸收和局部加热,但高效的冷却sink和下落包层的高ram压力阻止了任何核心坍缩超新星样爆炸。我们发现所有核合成材料(T > 5 GK)都严格地被引力束缚,挑战了这些系统通过对流 dredge-up 贡献显著银河系核合成产量的假设。缺乏持续流出和持续的超临界吸积率表明,嵌入的NS将在分钟到几小时内迅速超过Tolman-Oppenheimer-Volkoff质量极限。我们得出结论,这些系统不是稳定的TŻOs,而是灾难性黑洞形成和高能暂现源的短暂前体。

英文摘要

The evolution of neutron stars (NSs) embedded within massive stellar envelopes is a critical phase in binary stellar evolution, potentially leading to the formation of Thorne-Żytkow Objects (TŻOs) or catastrophic collapse. We present the first fully coupled general relativistic hydrodynamics (GRHD) simulations of hypercritical accretion onto NSs that simultaneously incorporate grey two-moment (M1) neutrino transport and an $α$-chain nuclear reaction network. By investigating four distinct progenitor evolutionary stages, we resolve the complex interplay between intense neutrino cooling, multidimensional fluid dynamics, and nuclear feedback. Our results show that while vigorous convection is triggered in the post-shock region, the global energy budget is primarily governed by neutrino cooling, which effectively balances the accretion power. Crucially, even though our M1 transport scheme captures neutrino absorption and localized heating, the efficient cooling sink and high ram pressure of the infalling envelope prevent the formation of any core-collapse supernova-like explosion. We find that all nucleosynthetically processed material ($T > 5$~GK) remains strictly gravitationally bound, challenging the assumption that these systems contribute significantly to galactic nucleosynthetic yields via convective dredge-up. The lack of sustained outflows and the persistent hypercritical accretion rates suggest that embedded NSs will rapidly exceed the Tolman-Oppenheimer-Volkoff mass limit on timescales of minutes to hours. We conclude that these systems are not stable TŻOs, but are rather transient precursors to catastrophic black hole formation and potential central engines for high-energy transients.

2604.23303 2026-06-05 hep-ph

Two-loop quarkonium Hamiltonian in annihilation channel

双环夸克onium哈密顿量在湮灭通道中

Yukinari Sumino, Takahiro Ueda

AI总结 本文基于势-非相对论量子色动力学有效场论框架,计算了双环夸克onium哈密顿量在湮灭通道中的结果,并将其与SU(N)色规范群中的四夸克算符先前计算结果一致,进一步推导出适用于其他规范群的更一般色结构表达式,结合非湮灭通道的双环哈密顿量计算,完成完整的双环夸克onium哈密顿量。

Comments 12 pages, 3 figures, 2 ancillary files containing analytical expressions; v2: version published in Phys. Lett. B

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AI中文摘要

我们在势-非相对论量子色动力学有效场论框架内计算了湮灭通道中的双环夸克onium哈密顿量。结果与NRQCD中对应四夸克算符的先前计算结果一致。我们进一步推导出适用于其他规范群的更一般色结构表达式。结合最近计算的非湮灭通道双环哈密顿量,这完成了完整的双环夸克onium哈密顿量。

英文摘要

We calculate the two-loop quarkonium Hamiltonian in the annihilation channel within the framework of potential-NRQCD effective field theory. The result agrees with the previous calculation of the corresponding four-quark operator in NRQCD for SU(N) color gauge group. We further obtain an expression with a more general color structure applicable to other gauge groups. Combined with the recently calculated two-loop Hamiltonian in the non-annihilation channel, this completes the full two-loop quarkonium Hamiltonian.

2604.21183 2026-06-05 math.CO

3-Designs from $\mathrm{GL}_2(\mathbb{F}_q)$-Invariant Subspaces of $\mathbb F_q[X,Y]_k$

来自 $\mathbb F_q[X,Y]_k$ 的 $\mathrm{GL}_2(\mathbb{F}_q)$-不变子空间的 $3$-设计

Lewen Wang, Huawei Wu, Sihuang Hu

AI总结 本文提出一个统一框架,通过 $\mathrm{GL}_2(\mathbb{F}_q)$-不变子空间构造 $3$-设计,并利用 Cayley 变换将构造转化为单位圆上的线性关系,统一了多种现有构造,简化了计算;当 $k\le q$ 时,通过射影 Reed-Solomon 码的子码给出设计非空的条件,并应用于 Lucas 子空间得到 Steiner 系统 $S(3,p^m+1,q+1)$ 等结果。

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AI中文摘要

我们提出了一个统一框架,用于从 $\mathbb F_q[X,Y]_k$($k$ 次齐次多项式空间)的 $\mathrm{GL}_2(\mathbb F_q)$-不变子空间构造 $3$-设计。给定这样一个子空间 $W$,我们关联一个 $\mathrm{PGL}_2(\mathbb F_q)$-不变的 $\mathbb P^1(\mathbb F_q)$ 的 $k$-子集族。只要该族非空,它就形成一个 $3\text{-}(q+1,k,\lambda)$ 设计。通过 Cayley 变换,该构造在单位圆 $U_{q+1}\subseteq \mathbb F_{q^2}^{\times}$ 上重新表述,其中块条件变为初等对称多项式之间的显式线性关系。这一重新表述统一了先前几种不同的构造,并简化了许多精细的临时计算。当 $k\le q$ 时,$\mathbb P^1(\mathbb F_q)$ 上的赋值映射将 $W$ 等同于射影 Reed-Solomon 码的子码 $C_W$。我们证明,相关的块族非空当且仅当 $d(C_W)=q+1-k$。在此条件下,$C_W$ 中最小重量码字的支撑以及其对偶码 $C_W^\perp$ 中适当固定重量码字的支撑进一步产生 $3$-设计。将该框架应用于 Lucas 子空间(一类特殊的不变子空间),我们得到了显式的块描述,分类了定义条件简化为单一方程的情形,并建立了若干非空与空性结果。特别地,对于 $q=p^e$ 和 $k=p^m+1$,我们证明相关的块族非空当且仅当 $m\mid e$,此时它产生 Steiner 系统 $S(3,p^m+1,q+1)$。最后,在三元情形 $p=3$ 和 $k=7$ 中,我们利用三元 Melas 码的重量分布确定了 Xu 等人未确定的设计参数。

英文摘要

We present a uniform framework for constructing $3$-designs from $\mathrm{GL}_2(\mathbb F_q)$-invariant subspaces of $\mathbb F_q[X,Y]_k$, the space of homogeneous polynomials of degree $k$. Given such a subspace $W$, we associate a $\mathrm{PGL}_2(\mathbb F_q)$-invariant family of $k$-subsets of $\mathbb P^1(\mathbb F_q)$. Whenever this family is nonempty, it forms a $3\text{-}(q+1,k,λ)$ design. Via the Cayley transform, the construction is reformulated on the unit circle $U_{q+1}\subseteq \mathbb F_{q^2}^{\times}$, where the block conditions become explicit linear relations among elementary symmetric polynomials. This reformulation unifies several previously disparate constructions and simplifies a number of delicate ad hoc computations. When $k\le q$, the evaluation map on $\mathbb P^1(\mathbb F_q)$ identifies $W$ with a subcode $C_W$ of the projective Reed--Solomon code. We show that the associated block family is nonempty if and only if $d(C_W)=q+1-k$. Under this condition, the supports of minimum-weight codewords in $C_W$, as well as the supports of suitable fixed-weight codewords in the dual code $C_W^\perp$, yield further $3$-designs. Applying this framework to the Lucas subspaces, which form a distinguished family of invariant subspaces, we obtain explicit block descriptions, classify the cases in which the defining conditions reduce to a single equation, and establish several emptiness and nonemptiness results. In particular, for $q=p^e$ and $k=p^m+1$, we show that the associated block family is nonempty if and only if $m\mid e$, in which case it yields the Steiner system $S(3,p^m+1,q+1)$. Finally, in the ternary case $p=3$ and $k=7$, we use the weight distribution of the ternary Melas code to determine the design parameters left undetermined by Xu et al.

2601.08715 2026-06-05 math.CO math.GR

A Lower Bound for the Diameter of Cayley Graph of the Symmetric Group $S_n$ Generated by $(12), (12 \dots n), (1n \dots 2)$

关于对称群$S_n$的Cayley图直径的下界

Grigorii Antiufeev

AI总结 本文研究了对称群$S_n$中元素$s(1n \dots 2)^{i}$分解复杂度的下界,并由此得出由生成元$(12)$、$(12 \dots n)$和$(1n \dots 2)$生成的Cayley图直径的下界为$n(n-1)/2$。

Comments 11 pages

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AI中文摘要

我们使用方括号表示对称群$S_n$中的元素,用圆括号表示循环。在此约定下,恒等元$()$的完全反转是元素$s = [n\ n-1 \dots 1]$。在本文中,我们获得了元素$s(1n \dots 2)^{i}$分解成生成元$(12)$、$(12 \dots n)$和$(1n \dots 2)$的分解复杂度的下界。作为结果,我们得出由生成元$(12)$、$(12 \dots n)$和$(1n \dots 2)$生成的对称群$S_n$的Cayley图直径的下界为$n(n-1)/2$。

英文摘要

Let us denote elements of the symmetric group $S_n$ using square brackets for the one-line notation. Cycles will be represented using parentheses, following the standard cycle notation. Under this convention, the full reversal of the identity element $()$ is the element $s = [n\ n-1 \dots 1]$. In the present work, we obtain a lower bound on the decomposition complexity of elements $s(1n \dots 2)^{i}$ into the generators $(12), (12 \dots n), (1n \dots 2)$, where $i$ ranges over the set $\{1,2,\dots,n\}$. As a consequence, we derive the lower bound $n(n-1)/2$ for the diameter of Cayley graph of the group $S_n$ generated by $(12), (12 \dots n), (1n \dots 2)$.

2408.06765 2026-06-05 physics.class-ph physics.comp-ph

Efficient numerical frameworks for modelling ultrasonic beams propagating across interfaces

高效数值框架用于建模超声束跨界面传播

André Lello de Almeida, Melody Png, Bo Lan

AI总结 本文提出两种不同的框架来建模由换能器产生的波场通过一个或多个界面传播,并采用准蒙特卡洛积分方案进行数值评估。第一种方法基于瑞利-索默菲尔德积分,进一步发展了文献中的公式并改进了其能力,而第二种方法则依赖于高频近似,采用射线追踪原理。通过深入研究多个应用场景,比较了每种模型的优缺点,并进行了效率和范围评估。结果表明,当需要大量场点时,基于RSI的模型表现良好,例如在建模完整场图像时;相反,当有大量界面时,如建模通过薄层材料的场,最有效的模型是射线追踪公式,因为不需要首先将场传播到所有界面之间。这在仅需在多个界面另一侧的几个点上评估场的应用中尤为明显。

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AI中文摘要

两种不同的框架被开发用于建模由换能器产生的波场并通过一个或多个界面传播,并采用准蒙特卡洛(QMC)积分方案进行数值评估。第一种方法基于瑞利-索默菲尔德积分(RSI),进一步发展了文献中的公式并改进了其能力,而第二种方法则依赖于高频近似,采用射线追踪原理。通过深入研究多个应用场景,比较了每种模型的优缺点,并进行了效率和范围评估。结果表明,当需要大量场点时,基于RSI的模型表现良好,例如在建模完整场图像时;相反,当有大量界面时,如建模通过薄层材料的场,最有效的模型是射线追踪公式,因为不需要首先将场传播到所有界面之间。这在仅需在多个界面另一侧的几个点上评估场的应用中尤为明显。

英文摘要

Two different frameworks are developed to model the wave field generated by a transducer and propagating through one or more interfaces, and a Quasi-Monte Carlo (QMC) integration scheme is used to numerically evaluate their results. The first method is based on the Rayleigh-Sommerfeld Integral (RSI), further developing a formulation in the literature and improving its capabilities, while the second relies on a high-frequency approximation, using a ray tracing principle. The advantages and limitations of each model are then compared via in-depth investigations on several use cases, culminating in an efficiency and scope assessment. It was found that the RSI-based model performs well if a large number of field points is needed, such as when modelling a full image of the field. Conversely, for a large number of interfaces, such as when modelling the field through a thin-layered material, the most efficient model was the ray tracing formulation, since it was unnecessary to propagate the field between all the interfaces first. This was especially noticeable for applications requiring only the evaluation of the field at a few points on the other side of multiple interfaces.

2604.20396 2026-06-05 math.AP

Infinite time blow-up and slow decay for the six dimensional energy-critical heat equation with self-similarly decaying initial data

六维能量临界热方程中自相似衰减初始数据的无限时间爆破与慢衰减

Kotaro Hisa, Jin Takahashi, Erbol Zhanpeisov

AI总结 研究六维能量临界半线性热方程中自相似衰减初始数据的解,发现存在符号变化的解在无限时间内爆破,以及衰减速度严格慢于自相似速率的非负解,证明爆破和衰减速率不唯一由初始数据衰减率决定。

Comments 25 pages

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AI中文摘要

我们考虑六维能量临界半线性热方程的自相似衰减初始数据。我们的主要结果表明,存在符号变化的解,其表现出无限时间爆破和非负解,其衰减速度严格慢于自相似速率。此外,爆破和衰减速率不唯一由初始数据的衰减率决定,而是取决于构造。证明基于将适当缩放的泡状结构与正向自相似解结合。

英文摘要

We consider the six dimensional energy-critical semilinear heat equation with self-similarly decaying initial data. Our main result shows the existence of sign-changing solutions that exhibit infinite-time blow-up and nonnegative solutions that decay strictly more slowly than the self-similar rate. Moreover, the blow-up and decay rates are not uniquely determined by the decay rate of the initial data, but exhibit a certain flexibility depending on the construction. The proof is based on gluing suitably rescaled bubbles to forward self-similar solutions.

2509.08781 2026-06-05 eess.IV

Hadamard-Based Recursive Aperture Decoded Ultrasound Imaging (READI) With Estimated Motion-Compensated Compounding (EMC2) Using Top-Orthogonal to Bottom Electrode (TOBE) Arrays

基于Hadamard矩阵的递归孔径解码超声成像(READI)与估计运动补偿复合(EMC2)使用顶部-垂直到底部电极(TOBE)阵列

Tyler Keith Henry, Darren Dahunsi, Randy Palamar, Negar Majidi, Ying Wan, Mohammad Rahim Sobhani, Afshin Kashani Ilkhechi, Roger Zemp

AI总结 本文提出了一种基于Hadamard矩阵的递归孔径解码超声成像(READI)和估计运动补偿复合(EMC2)方法,利用TOBE阵列减少运动敏感性,提高成像质量。

Comments 21 pages, 19 figures

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AI中文摘要

基于Hadamard矩阵的孔径编码是一种产生高信噪比合成孔径数据集的方法。最近,偏置敏感的顶部-垂直到底部电极(TOBE)阵列的脉冲反转能力推动了多种基于Hadamard的序列的发展。这些序列能产生高质量的静态图像,但对运动敏感。本文引入了递归孔径解码成像(READI)和估计运动补偿复合(EMC2),旨在减少这种敏感性。READI是一种新的解码和波束成形技术,用于Hadamard孔径编码序列,能从序列的子集生成多个低分辨率图像。这些READI图像受运动影响较小,可以相加形成完整的高分辨率图像。EMC2描述了将这些低分辨率图像进行比较以估计底层运动,然后进行变形以对齐后再复合的过程。这会产生一个对运动具有鲁棒性的高分辨率图像。将READI与EMC2应用于基于TOBE的快速正交行-列电子扫描(FORCES)序列。证明其能完全恢复被探头运动破坏的图像,并在心跳仿真实验中恢复组织散射和边界。单独的READI低分辨率图像在相同发射次数下比稀疏Hadamard方案有显著改进,并能以42 cm/s的流速恢复血液散射。

英文摘要

Hadamard matrix-based aperture encoding is a method for producing synthetic aperture datasets with high Signal-to-Noise Ratios. Recently, the pulse inversion capabilities of bias-sensitive Top-Orthogonal to Bottom Electrode (TOBE) arrays have driven the development of multiple Hadamard-based sequences. These sequences produce high-quality static images but are sensitive to motion. This work introduces Recursive Aperture Decoded Imaging (READI) and Estimated Motion-Compensated Compounding (EMC2), which look to reduce this sensitivity. READI is a novel decoding and beamforming technique for Hadamard aperture-encoded sequences that produces multiple low-resolution images from subsets of the full sequence. These READI images are less affected by motion and sum to form the complete high-resolution image. EMC2 describes the process of comparing these low-resolution images to estimate the underlying motion, then warping them to align before compounding. This produces a high-resolution image that is resiliant to motion. READI with EMC2 applied to the TOBE-based Fast Orthogonal Row-Column Electronic Scanning (FORCES) sequence. It is shown to fully restore images corrupted by probe motion and to recover tissue speckle and boundaries in images of a beating heart phantom. READI low-resolution images by themselves are demonstrated to be a marked improvement over a sparse Hadamard scheme with the same transmit count, and are able to recover blood speckle at a flow rate of 42 cm/s.

2511.15000 2026-06-05 cs.PL cs.DB

Bonsai: Compiling Queries to Pruned Tree Traversals

Bonsai:编译为修剪树遍历的查询

Alexander J Root, Christophe Gyurgyik, Purvi Goel, Kayvon Fatahalian, Jonathan Ragan-Kelley, Andrew Adams, Fredrik Kjolstad

AI总结 本文提出了一种通用的方法,通过符号区间分析和几何谓词规则,自动推导出支持广泛连接谓词的通用单索引和双索引树连接,从而实现高效的查询编译。

Journal ref Proc. ACM Program. Lang. 10, PLDI, Article 178 (June 2026)

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AI中文摘要

树可以加速对大规模集合进行搜索或聚合值的查询。它们通过存储元数据来实现这一点,该元数据允许在谓词证明子树中的数据不影响查询结果时快速剪枝(或包含)子树。现有系统为每个查询谓词和数据结构手动实现这种剪枝逻辑。我们泛化并机械地实现了这一类优化。我们的方法推导出何时可以剪枝(或完整包含)子树的条件,这些条件以每个节点可用的元数据表达。我们使用符号区间分析高效地生成这些条件,扩展了新的规则以处理几何谓词(例如,相交、包含)。此外,我们的编译器将复合查询(例如,对过滤器的缩减)融合为单一的树遍历。这些技术使能够自动推导出支持广泛连接谓词的通用单索引和双索引树连接,这些连接支持超越标准等值和范围谓词的广泛连接谓词类别。生成的遍历行为与专家编写代码实现的查询特定遍历行为一致,并且在手写情况不适用时,可以渐进优于线性扫描和嵌套循环连接。

英文摘要

Trees can accelerate queries that search or aggregate values over large collections. They achieve this by storing metadata that enables quick pruning (or inclusion) of subtrees when predicates on that metadata can prove that none (or all) of the data in a subtree affect the query result. Existing systems implement this pruning logic manually for each query predicate and data structure. We generalize and mechanize this class of optimization. Our method derives conditions for when subtrees can be pruned (or included wholesale), expressed in terms of the metadata available at each node. We efficiently generate these conditions using symbolic interval analysis, extended with new rules to handle geometric predicates (e.g., intersection, containment). Additionally, our compiler fuses compound queries (e.g., reductions on filters) into a single tree traversal. These techniques enable the automatic derivation of generalized single-index and dual-index tree joins that support a wide class of join predicates beyond standard equality and range predicates. The generated traversals match the behavior of expert-written code that implements query-specific traversals, and can asymptotically outperform the linear scans and nested-loop joins that existing systems fall back to when hand-written cases do not apply.

2604.19461 2026-06-05 cs.CR

Involuntary In-Context Learning: Exploiting Few-Shot Pattern Completion to Bypass Safety Alignment in GPT-5.4

强制性上下文学习:利用少样本模式完成来绕过GPT-5.4的安全对齐

Alex Polyakov, Daniel Kuznetsov

AI总结 本文提出了一种称为强制性上下文学习(IICL)的攻击方法,通过使用少量示例的抽象操作符框架来强制模式完成,从而绕过大型语言模型的安全对齐训练。通过在10个OpenAI模型上进行3479次测试,研究发现语义操作符命名可以实现100%的绕过率,抽象框架是攻击的关键,而示例顺序和温度参数对攻击效果有显著影响。

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AI中文摘要

大型语言模型的安全对齐依赖于行为训练,但当足够强的上下文模式与已学习的拒绝行为竞争时,这种训练可能会被覆盖。我们引入了强制性上下文学习(IICL)攻击类别,该攻击利用少量示例的抽象操作符框架来强制模式完成,从而绕过安全训练。通过在10个OpenAI模型上进行3479次测试,我们通过七次实验消融研究确定了攻击的有效组件。关键发现:(1)语义操作符命名实现了100%的绕过率(50/50,p < 0.001);(2)攻击需要抽象框架,因为直接问答格式的相同示例导致0%;(3)示例顺序影响显著(交错:76%,有害优先:6%);(4)温度参数无显著影响(0.0-1.0范围内为46-56%)。在HarmBench基准测试中,IICL在GPT-5.4上实现了24.0%的绕过率[18.6%, 30.4%],通过详细的619字响应,相比直接查询的0.0%。

英文摘要

Safety alignment in large language models relies on behavioral training that can be overridden when sufficiently strong in-context patterns compete with learned refusal behaviors. We introduce Involuntary In-Context Learning (IICL), an attack class that uses abstract operator framing with few-shot examples to force pattern completion that overrides safety training. Through 3479 probes across 10 OpenAI models, we identify the attack's effective components through a seven-experiment ablation study. Key findings: (1)~semantic operator naming achieves 100% bypass rate (50/50, $p < 0.001$); (2)~the attack requires abstract framing, since identical examples in direct question-and-answer format yield 0%; (3)~example ordering matters strongly (interleaved: 76%, harmful-first: 6%); (4)~temperature has no meaningful effect (46-56% across 0.0--1.0). On the HarmBench benchmark, IICL achieves 24.0% bypass $[18.6%, 30.4%]$ against GPT-5.4 with detailed 619-word responses, compared to 0.0% for direct queries.

2511.09311 2026-06-05 hep-ph astro-ph.CO astro-ph.GA

A Unified Dark-Matter--Driven Relativistic Bondi Route to Black-Hole Growth from Stellar to Supermassive Scales

暗物质驱动的广义相对论Bondi路线:从恒星到超大质量黑洞的统一增长途径

Chian-Shu Chen, Feng-Li Lin

AI总结 该研究提出了一种基于自相互作用暗物质(SIDM)的超埃德蒙顿吸积机制,通过近相对论声速的临界状态,使暗物质吸积率仅依赖于SIDM的质量,从而在宇宙早期将原始黑洞种子增长为超大质量黑洞。

Comments 8 pages, 5 figures, match with the ApJL published version, but with an additional appendix to clarify the usual no-go for the usual Bondi accretion mechanism for SMBHs; v4 correcting a minor typo on Eq. (6) and (S23)

Journal ref Astrophys.J.Lett. 1001 (2026) 2, L39

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AI中文摘要

观测到红移z>7的明亮类星体揭示了在宇宙历史的前700 Myr内形成的质量约为10^9 M_sun的超大质量黑洞(SMBH)。标准增长通道——埃德蒙顿限制气体吸积和分层并合——面临严重的时间尺度限制。我们考虑了一种由最小模型自相互作用暗物质(SIDM)驱动的超埃德蒙顿吸积机制。我们证明在近相对论声速的临界状态下,Bondi吸积率仅依赖于SIDM的质量m,因此与周围环境无关。这种临界吸积机制对于m>10^-2 eV的SIDM,可以在宇宙早期将质量为10 M_sun的原始黑洞(PBH)种子增长为质量在10^9-10^10 M_sun范围内的SMBH,直至z≈7,无需精细调制环境。因此,给定PBH的质量分布和m值,晚期时间的主要黑洞质量函数可以完全确定,质量范围从恒星质量到SMBH。这将微观的暗物质物理与天体物理黑洞观测连接起来。

英文摘要

Observations of luminous quasars at $z\gtrsim7$ reveal supermassive black holes (SMBHs) with inferred masses $M_{\rm BH}\sim10^9 \, M_\odot$ formed within the first $\sim700$~Myr of cosmic history. Standard growth channels \textrm{ -- } Eddington-limited gas accretion and hierarchical mergers \textrm{ -- } face severe timescale restrictions. We consider a super-Eddington accretion mechanism aided by the Bondi accretion of a minimal model of self-interacting dark matter (SIDM). We demonstrate that in a {\it critical regime} with a near-relativistic sound speed, the Bondi accretion yields an accretion rate that depends only on the mass $m$ of SIDM, thus it is universal to the ambient environment. This critical accretion mechanism for $m\gtrsim 10^{-2}\; {\rm eV}$ can grow seeds as small as $10\,M_\odot$ primordial black holes (PBH) in the early Universe into $10^9$ \textrm{--} $10^{10}\,M_\odot$ SMBHs by $z\sim7$ without fine-tuned environments. Therefore, given a mass distribution of PBHs and a value of $m$, the mass function of primary black holes at late time can be fully determined with masses ranging from stellar to SMBHs. This connects the microscopic physics of dark matter to astrophysical observations of black holes.

2604.17729 2026-06-05 cond-mat.mtrl-sci

Seed Layer Engineering for Effective Charge Transfer Doping of MoS$_2$ Transistors

用于有效电荷转移掺杂MoS₂晶体管的种子层工程

Sahej Sharma, Shao-Heng Yang, Himani Jawa, Rana Yuvraj, Bach Nguyen, Chang Niu, Shiva Radhakrishnan, Shalini Tripathi, Dennis Lin, Cesar Javier Lockhart de la Rosa, Pierre Morin, Dmitry Zemlyanov, Francesca Iacopi, Zhihong Chen, Joerg Appenzeller, Thomas E. Beechem

AI总结 研究通过种子层工程调控MoS₂晶体管的电荷转移掺杂,发现种子层厚度和沉积条件对阈值电压和导通电流有显著影响,利用多模光谱技术揭示了种子层对界面电荷环境的调控作用。

Comments 27 pages, 7 figures

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AI中文摘要

将二维半导体如MoS₂与介电材料集成仍然是未来逻辑技术中使用这些材料的核心挑战。虽然种子层通常用于促进介电成核和附着力,但我们表明它们也关键地调控电荷转移掺杂以及由此产生的晶体管性能。通过在MoS₂顶部表面制备Ta种子/HfO_x介电堆叠并对其进行电和物理表征,利用拉曼光谱、荧光光谱和X射线光电子能谱进行了研究。阈值电压和导通电流强烈依赖于Ta种子厚度和沉积条件,并且这些变化与所有光谱探针观测到的特征相关。结果表明,种子层不仅向MoS₂通道引入了散射,还修改了界面电荷环境,控制HfO_x和MoS₂之间的电荷转移。光谱学显示导通电流与种子引起的散射有关,而X射线光电子能谱表明阈值电压与界面电荷转移相关的局部静电环境位移有关。在氧气贫乏条件下沉积的超薄0.2 nm Ta种子层获得了更好的性能,这限制了沉积引起的损伤并促进了电荷转移。这些发现将种子层工程确定为控制MoS₂器件中散射和界面掺杂的关键策略,并确立了多模光谱作为在制造过程中用于工艺开发和监控的实用方法。

英文摘要

Integrating two-dimensional semiconductors such as MoS$_2$ with dielectric materials remains a central challenge for their use in future logic technologies. While seed layers are typically introduced to promote dielectric nucleation and adhesion, we show that they also critically govern charge-transfer doping and, in turn, transistor performance. Back-gated monolayer MoS$_2$ transistors passivated on their top-surface with a Ta-seed/HfO$_x$ dielectric stack were fabricated and characterized electrically and physically using Raman, photoluminescence, and X-ray photoelectron spectroscopies. Threshold voltage and on-current varied strongly with Ta-seed thickness and deposition conditions, and these changes correlated with signatures observed across all spectroscopic probes. The results reveal that the seed layer both introduces disorder into the MoS$_2$ channel and modifies the interfacial charge environment controlling charge transfer between HfO$_x$ and MoS$_2$. Optical spectroscopy shows that on-current tracks seed-induced disorder, whereas X-ray photoelectron spectroscopy indicates that threshold voltage correlates with shifts in the local electrostatic environment associated with interfacial charge transfer. Better performance was obtained with ultrathin 0.2 nm Ta seed layers deposited under oxygen-poor conditions, which limit deposition-induced damage while facilitating charge transfer. These findings identify seed-layer engineering as a key strategy for controlling disorder and interfacial doping in MoS$_2$ devices and establish multimodal spectroscopy as a practical during-fabrication approach for process development and monitoring.

2604.15596 2026-06-05 cs.CR

Privacy, Prediction, and Allocation

隐私、预测与分配

Ben Jacobsen, Nitin Kohli

AI总结 研究在满足差分隐私的援助分配系统中,个体级与单位级分配策略在隐私、效率和目标精度之间的权衡。

Comments 2026 FORC (Foundations of Responsible Computing)

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AI中文摘要

算法预测越来越多地被用于指导稀缺资源的分配。这些方法的承诺是,通过机器学习,它们能够更好地识别那些能从干预中受益最多的人。然而,最近一些研究通过证明存在简单、单位级分配策略能够达到甚至超过基于个体级定位的策略性能的设置,对这一假设提出了质疑。另外,其他研究出于隐私原因反对个体级定位,导致了一种不寻常的情况:出于隐私和效用两方面的原因,推荐使用单一解决方案——单位级定位。出于充分理解隐私与定位级别相互作用的愿望,我们启动了满足差分隐私的援助分配系统的研究,将现有的关于私有优化的研究与非私有文献中使用的援助分配经济模型相结合。为此,我们在数据可用性的一系列约束下,研究了随机和无分布设置中个体级和单位级分配策略的私有变体。通过这一分析,我们提供了清晰、可解释的界限,刻画了隐私、效率和目标精度之间的权衡。

英文摘要

Algorithmic predictions are increasingly used to inform the allocation of scarce resources. The promise of these methods is that, through machine learning, they can better identify the people who would benefit most from interventions. Recently, however, several works have called this assumption into question by demonstrating the existence of settings where simple, unit-level allocation strategies can meet or even exceed the performance of those based on individual-level targeting. Separately, other works have objected to individual-level targeting on privacy grounds, leading to an unusual situation where a single solution, unit-level targeting, is recommended for reasons of both privacy and utility. Motivated by the desire to fully understand the interplay of privacy and targeting levels, we initiate the study of aid allocation systems that satisfy differential privacy, synthesizing existing works on private optimization with the economic models of aid allocation used in the non-private literature. To this end, we investigate private variants of both individual and unit-level allocation strategies in both stochastic and distribution-free settings under a range of constraints on data availability. Through this analysis, we provide clean, interpretable bounds characterizing the tradeoffs between privacy, efficiency, and targeting precision in allocation.

2604.15185 2026-06-05 physics.optics

Picometer-Scale Spatial Symmetry Breaking in Active Transmissive Metasurfaces

皮米尺度空间对称性破缺在活性透射元表面中

Martin Thomaschewski, Ruzan Sokhoyan, Elisabetta Schneider, Harry Atwater

AI总结 本文研究了基于硅-锂铌酸盐的活性透射元表面,通过皮米级精确控制实现高Q值的引导模共振,利用对称性破缺实现高效电光调制和多功能传感。

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AI中文摘要

活性透射元表面是未来紧凑、可级联光学系统的核心构建模块,能够实现多个功能层的堆叠以实现先进的动态光束成形、光子神经网络、深度传感和全息成像。我们提出了一种基于硅-锂铌酸盐的透射电光元表面,其中一组具有周期性扰动的硅波导,可在皮米尺度上单独控制,支持定义良好的高Q值(>2000)引导模共振(GMRs)。我们通过在子波长间隔的GMR元件之间集成梳状推拉电极,局部调节锂铌酸盐基底的折射率,从而移位GMR共振并使相邻辐射元件之间实现相位和幅度的相反调制。在几何对称的元表面中,这种效应通过衍射产生电光束分裂,衍射效率高达3%。通过引入通过皮米尺度扰动移位实现的受控被动共振漂移,我们实现了通过几何对称性破缺实现的文纳型增强机制,从而将幅度调制效率提高了六倍,并在±30 V时实现40%的调制深度。本工作展示了由高Q值GMR结构 enabled 的活性和被动共振控制在高效电光调制或多功能传感方面的潜力。

英文摘要

Active transmissive metasurfaces are central building blocks for future compact, cascadable optical systems, enabling the stacking of multiple functional layers for advanced dynamic beam shaping, photonic neural networks, depth sensing, and holography. We present a transmissive electro-optic metasurface based on silicon-on-lithium-niobate, where an array of silicon waveguides with periodic perturbations, individually controlled at the 100 pm scale, supports well-defined high-Q (>2000) guided-mode resonances (GMRs). We incorporate interdigitated push-pull electrodes between subwavelength-spaced GMR elements to locally tune the refractive index in the lithium niobate substrate, thereby shifting the GMR resonance and enabling opposite phase and amplitude modulation between neighboring radiative elements. In a geometrically symmetric metasurface, this effect introduces electro-optic beam splitting via diffraction, with diffraction efficiencies as high as 3%. By introducing controlled passive resonance detuning via 100 pm scale perturbation shifts, we realize a Vernier-type enhancement mechanism through geometrical symmetry breaking, thereby increasing the efficiency of amplitude modulation six-fold , and achieving modulation depths of 40% at $\pm$30 V. This work demonstrates the potential of active and passive resonance control enabled by high-Q GMR structures for efficient electro-optic modulation or multifunctional sensing.

2604.15014 2026-06-05 quant-ph

Hybrid physical/logical zero-noise extrapolation with limited logical executions

混合物理/逻辑零噪声扩展与有限逻辑执行

D. V. Babukhin, W. V. Pogosov

AI总结 本文提出了一种混合策略,通过结合逻辑电路和物理折叠电路,利用零噪声扩展方法在有限逻辑执行资源下减少运行时间,同时推导了Richardson方差预因子、折叠电路运行时间比率、最优射频分配和偏差-方差准则。

Comments 31 pages, 7 figures

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AI中文摘要

在完全故障容忍之前,部分错误纠正的逻辑执行可能可用但成本较高。我们将零噪声扩展视为一个统计设计问题,其中物理/逻辑执行模式是扩展变量。逻辑电路提供低噪声锚点,而物理折叠电路提供更便宜的噪声杠杆。在校准的$p_L=γp$模型中,我们推导了Richardson方差预因子、折叠电路运行时间比率、最优射频分配和偏差-方差准则。我们证明,对于$γ\lesssim0.1$,混合策略可以在所陈述的资源模型下显著减少运行时间。

英文摘要

Before full fault tolerance, partially error-corrected logical executions may be available but costly. We formulate zero-noise extrapolation as a statistical-design problem in which the physical/logical execution mode is an extrapolation variable. Logical circuits provide low-noise anchors, while physical folded circuits supply a cheaper noise lever arm. In a calibrated $p_L=γp$ model, we derive Richardson variance prefactors, folded-circuit runtime ratios, optimal shot allocation, and bias--variance criteria. We demonstrate that for $γ\lesssim0.1$, the mixed strategy can substantially reduce runtime under the stated resource model.

2604.14764 2026-06-05 cond-mat.mtrl-sci physics.comp-ph

Nonmagnetic-magnetic Transitions in Rutile RuO2

二氧化钌 rutile 中的非磁性-磁性相变

Yue-Fei Hou, Siyuan Liu, Wanxiang Fen, Jiajun Lu, Xinfeng Chen, Gui-Bin Liu, Ping Zhang

AI总结 研究通过密度泛函理论计算揭示了二氧化钌 rutile 中磁性与非磁性相变的关联性和应变依赖性,探讨了其在不同 Hubbard 参数空间中的多种交替磁性相,并展示了应变对晶格体积的影响下,非磁性和磁性态之间的转变。

Comments 20 pages, 6 figures

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AI中文摘要

二氧化钌 rutile 近年来引起了广泛关注,因其基态磁性仍存在争议。实验研究在不同晶态样品中报告了非磁性(NM)或交替磁性(AM)基态,突显了需要合理解释以解决这一矛盾的必要性。在本研究中,通过密度泛函理论计算揭示了 bulk 二氧化钌 rutile 的关联性和应变依赖性磁性。一方面,在 RuO$_2$ 的 Hubbard 参数空间中识别出多种具有不同自旋磁矩大小的 AM 相。另一方面,当施加适当应变显著改变晶格体积时,RuO$_2$ 的基态可以在无自旋分裂的 NM 态和具有带结构中自旋分裂的磁性态之间发生转变。这些发现不仅展示了 4 extit{d} 电子关联 RuO$_2$ 中引人入胜的物理特性,还保留了其在自旋电子学应用中的潜力。

英文摘要

Rutile RuO$_2$ has recently attracted great interest, as its magnetic ground state remains controversial. Experimental studies have reported either nonmagnetic (NM) or altermagnetic (AM) ground states in different crystalline samples of RuO$_2$, highlighting the need for a reasonable explanation to resolve this contradiction. In this study, density functional theory calculations are performed to reveal the correlation-sensitive and strain-dependent magnetism of bulk RuO$_2$. On one hand, multiple AM phases with different magnitudes of the spin magnetic moment are identified in the Hubbard parameter space for RuO$_2$. On the other hand, when appropriate strains that significantly change the crystal cell volume are applied, the ground state of RuO$_2$ can undergo transitions between the NM state (with no spin splitting) and the magnetic states (with spin splitting in the band structure). These findings not only demonstrate intriguing physics in 4\textit{\textit{d}}-electron-correlated RuO$_2$, but also retain its potential for spintronic applications.

2604.14533 2026-06-05 cond-mat.str-el cond-mat.mes-hall cond-mat.quant-gas quant-ph

The Two Orbital, Interacting Hatano-Nelson Model

双轨道相互作用的Hatano-Nelson模型

Jonah Huang, Rubem Mondaini, Nancy Aggarwal, Richard Scalettar

AI总结 本文研究了在双链(双能带)几何结构中,考虑非厄米特性与相互作用的费米子系统,探讨了纯实谱存在的相图及边界条件对谱性质的影响。

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AI中文摘要

单轨道、一维的Hatano-Nelson哈密顿量提供了对非厄米特性物理的深刻见解,这种非厄米特性源于不对称的左右跃迁,并与局域化有关。在无杂波情况下,其单粒子本征值E_α在复平面上位于一个椭圆上,其虚轴范围由不对称程度控制。当引入随机性时,两个实本征值出现在E_α最大和最小实部的极端。这些实本征值与局域化的本征向量相关。对于无自旋费米子,增加近邻相互作用首先导致电荷密度波相变,最终在有限晶格中所有本征值坍缩到实轴。本文探讨了在双链(双能带)几何结构中,考虑非厄米特性和相互作用的自旋费米子系统中实本征值的存在情况,研究了实谱存在性的相图,作为相互作用强度、非厄米特程度和链间跃迁的函数。我们通过缠绕数分析研究了双链模型的边界条件对谱性质的敏感性,并探索了PBC双子态与OBC皮肤模式之间的关系。为了解决此类非平衡系统稳定性的问题,我们根据Lindbladian演化解低填充度下的动力学,并发现非厄米特描述能够定性地描述此类系统。

英文摘要

The single orbital, one-dimensional, Hatano-Nelson Hamiltonian provides deep insight into the physics of non-Hermiticity, resulting from asymmetric left/right hopping, and its connections to localization. In the absence of disorder, its single particle eigenvalues $E_α$ lie on an ellipse in the complex plane whose extent in the imaginary direction is controlled by the degree of asymmetry. When randomness is introduced, two sets of real eigenvalues emerge at the extremes of the largest and smallest real part of $E_α$. These real eigenvalues are associated with localized eigenvectors. For spinless fermions, increasing near-neighbor interactions first cause a transition to a charge density wave phase, and ultimately, on finite lattices, a collapse of all eigenvalues to the real axis. In this paper, we explore the presence of real eigenvalues in the interacting, two-particle sector for the spinful case (Hubbard model) in a two-chain (two-band) geometry with a Hermitian interchain hopping. Our key results are to obtain the ``phase" diagrams for the existence of a purely real spectrum, as a function of the interaction strength, degree of non-Hermiticity, and interchain hopping. We study the sensitivity to boundary conditions of the spectral properties of our two-chain model with winding number analysis and explore the relationship between PBC doublon states and OBC skin modes. To address the question of stability in such non-equilibrium systems, we solve the dynamics at low filling according to Lindbladian evolution and find that the non-Hermitian description is able to qualitatively describe such systems.

2604.14468 2026-06-05 cs.GR

Progressive Convex Hull Simplification

渐进凸包简化

Alec Jacobson

AI总结 本文提出了一种高效的O(n log n)贪心优化方法,用于在保持体积或表面积最小的前提下,保守地将凸包简化为指定数量的半空间,解决了传统方法在效率、紧致性和安全性方面的不足。

Comments accepted to be presented at Symposium on Geometry Processing 2026

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AI中文摘要

凸包在碰撞检测、光线相交和距离计算等任务中作为紧致包围盒很有用。不幸的是,多面体凸包的复杂性与输入成线性增长。我们考虑了将凸包保守地简化为指定数量的半空间,同时最小化增加的体积或表面积的问题。通过在对偶表示中工作,我们提出了一种高效的O(n log n)贪心优化。在比较中,我们展示了现有方法在效率、紧致性和安全性方面表现不佳。我们在各种输入形状和下游应用领域中展示了我们方法的成功。

英文摘要

Convex hulls are useful as tight bounding proxies for a variety of tasks including collision detection, ray intersection, and distance computation. Unfortunately, the complexity of polyhedral convex hulls grows linearly with their input. We consider the problem of conservatively simplifying a convex hull to a specified number of half-spaces while minimizing added volume or surface area. By working in the dual representation, we propose an efficient $O(n \log n)$ greedy optimization. In comparisons, we show that existing methods either exhibit poor efficiency, tightness or safety. We demonstrate the success of our method on a variety of input shapes and downstream application domains.

2601.13150 2026-06-05 stat.ME

Propensity Score Propagation: A General Framework for Design-Based Inference with Unknown Propensity Scores

倾向分数传播:一种用于未知倾向分数的设计基推断一般框架

Siyu Heng, Yanxin Shen, Zijian Guo

AI总结 本文提出了一种新的设计基推断框架,即倾向分数传播,用于处理未知倾向分数的情况。该框架通过再生与联合过程将倾向分数估计的不确定性传播到下游推断中,无需假设超总体结果分布。该方法兼容参数和非参数倾向分数模型,并能与现有基于已知倾向分数的设计基方法无缝集成,适用于广泛的设计基推断问题。理论结果和模拟研究显示,该框架在名义覆盖方面表现良好,即使现有方法存在显著的覆盖不足。

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AI中文摘要

设计基推断,也称为随机化基或有限总体推断,提供了一个原理性的框架,通过将随机性仅归因于设计机制(例如处理分配、调查抽样或缺失性),而无需对结果数据施加超总体分布或建模假设,从而实现可信的统计推断。从Fisher和Neyman的奠基性工作到最近设计基推断的复兴,这一观点在因果推断、调查抽样和缺失数据分析中发挥了核心作用。然而,一个基本障碍限制了其在许多现代应用中的使用:现有的设计基推断理论通常依赖于已知的倾向分数(即已知的设计概率),而倾向分数在观察性研究、现实世界调查设置和缺失数据问题中通常是未知的。本文提出倾向分数传播,一种用于未知倾向分数的有效设计基推断一般框架。该框架引入了再生与联合过程,将倾向分数估计的不确定性传播到下游的设计基推断中,而无需假设超总体结果假设。它兼容参数和非参数倾向分数模型,无缝集成现有基于已知倾向分数的设计基方法,并广泛应用于各种设计基推断问题。理论结果和模拟研究显示,所提出的框架实现了名义覆盖,即使现有方法表现出显著的覆盖不足。

英文摘要

Design-based inference, also known as randomization-based or finite-population inference, provides a principled framework for trustworthy statistical inference by attributing randomness solely to the design mechanism (e.g., treatment assignment, survey sampling, or missingness), without imposing super-population distributional or modeling assumptions on outcome data. From Fisher's and Neyman's seminal work to the recent resurgence of design-based inference, this perspective has played a central role in causal inference, survey sampling, and missing data analysis. However, a fundamental obstacle has limited its use in many modern applications: existing design-based inference theory typically relies on known propensity scores (i.e., known design probabilities), whereas propensity scores are usually unknown in observational studies, real-world survey settings, and missing data problems. We propose propensity score propagation, a general framework for valid design-based inference with unknown propensity scores. The framework introduces a regeneration-and-union procedure that propagates uncertainty from propensity score estimation into downstream design-based inference without imposing super-population outcome assumptions. It accommodates both parametric and nonparametric propensity score models, integrates seamlessly with existing design-based methods developed under known propensity scores, and applies broadly across design-based inference problems. Theoretical results and simulation studies show that the proposed framework achieves nominal coverage, even when existing approaches exhibit substantial under-coverage.

2604.14124 2026-06-05 astro-ph.EP

Icy Volatile Enhancements in Evolving Protoplanetary Disks

冰冻挥发物在演化的原行星盘中的增强

Elizabeth Yunerman, Ellen Price, Karin Öberg

AI总结 研究探讨了原行星盘中冰冻挥发物的增强机制,通过结合盘动态与简单的升华和沉积化学,揭示了挥发物在盘半径上的再分布作用,特别是对固态颗粒、行星esimal和行星组成的影响。

Comments 30 pages, 16 figures, 1 table. Accepted for publication in ApJ

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AI中文摘要

原行星盘中的冰冻线塑造了多种行星形成过程,通过演化设定环境组成。冰冻线位置取决于分子升华和沉积性质,但在动态盘中,温度和密度结构的变化也会影响行星和行星esimal的预期组成。在具有粒子漂流、热演化和脱附/吸附的湍流粘性盘中,Price等人(2021)表明,在CO冰线之外,CO/H2O冰的比例可增强约10倍。我们扩展了他们的工作,通过引入更多的碳、氮和氧物种,更多粒子尺寸,以及更广泛的盘参数探索。我们发现,在约0.5 Myr之前,随着外盘因漂流而干燥,挥发性冰相对于H2O增强;而在后期盘时间中,向外的对流和挥发性沉积进一步增加相对挥发性冰的增强,超过演化的临界盘半径。这些结合的相对冰冻增强机制相对于H2O的结果是固态C/O ~ N/O ~1,远高于静态盘的预期。超挥发物(N2、CO和CH4)在探索的参数空间中稳健地增加到约100倍,而中等挥发物(CO2和NH3)对模型选择敏感,增强范围从约2-50倍。这些结果表明,结合盘动态与简单的升华和沉积化学是预测颗粒、行星esimal和行星组成的关键,特别是对流在再分布挥发物方面的作用。

英文摘要

Protoplanetary disk ice lines shape a multitude of planet formation processes, setting the environmental composition through evolution. Ice line locations depend on molecular sublimation and deposition properties, but in dynamic disks where temperature and density structures change, so do the expected compositions of planets and planetesimals. In turbulent viscous disks with particle drift, thermal evolution, and desorption/adsorption, Price et al. 2021 demonstrated that the CO/H$_2$O ice ratio beyond the CO ice line can become enhanced by $\sim10\times$. We expand on their work by incorporating additional carbon, nitrogen, and oxygen species, more particle sizes, and a broader disk parameter exploration. We find that before $\sim0.5$Myr, volatile ices are enhanced relative to H$_2$O as the outer disk is desiccated by drift, while at later disk times outward advection and volatile deposition further increase relative volatile icy enhancements beyond the evolving critical disk radius. The outcome of these combined relative icy enhancement to H$_2$O mechanisms is solid C/O $\sim$ N/O $\sim1$ beyond the hypervolatile ice lines, much higher than expected in static disks. Hypervolatiles (N$_2$, CO, and CH$_4$) robustly increase to $\sim100\times$ across the explored parameter space, while mid-volatiles (CO$_2$ and NH$_3$) are sensitive to model choices, with enhancements ranging from $\sim2-50\times$. Together these results demonstrate that coupling disk dynamics with simple sublimation and deposition chemistry is fundamental to predicting grain, planetesimal, and planetary compositions, particularly the role of advection in redistributing volatiles across disk radii.

2604.13524 2026-06-05 quant-ph cs.IT math.IT

Quantum thermodynamics with uncertain equilibrium

具有不确定平衡的量子热力学

Munan Zhang, Kun Fang

AI总结 本文研究了量子热力学中平衡不确定性的核心问题,通过引入候选状态集来表征平衡参考,并证明了在通用几何条件下,将不确定的非热态转化为确定态是不可能的。研究还推导了两种工作存储模型的一次性熵特征,展示了即使在极小的不确定性下,两种模型仍表现出强的渐近不可逆性。

Comments comments are welcome

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AI中文摘要

量子热力学的资源理论方法通常假设对热平衡态有完美知识,这种理想化与有限实验精度不兼容。我们发展了一个平衡不确定性框架,将平衡参考表示为候选状态集。在通用几何条件下,我们证明了一个no-go定理,严格限制了非热态的“纯化”:将不确定的非热态转化为确定态要么是平凡的要么是不可能的。随后,我们推导了两种工作存储模型的一次性熵特征,即一个已知平衡的清洁电池和一个具有不确定平衡的脏电池。这两种模型即使在任意小的不确定性下也表现出强渐近不可逆性。一个显式例子揭示了两种不同的极端:清洁电池显示一种类似于边界纠缠的现象,具有正的形成成本但零可提取功,而脏电池允许正功提取但需要无限的形成成本。这些现象表明,平衡不确定性不是标准理论的小扰动,而是一个结构性成分,从根本上重塑了量子热力学的限制。

英文摘要

The resource-theoretic approach to quantum thermodynamics typically assumes perfect knowledge of the thermal equilibrium state, an idealization incompatible with finite experimental precision. We develop a framework for equilibrium uncertainty by representing the equilibrium reference as a set of candidate states. Under a generic geometric condition, we prove a no-go theorem that sharply limits athermality ``purification'': converting an uncertain athermal state into a definite target is either trivial or impossible. We then derive exact one-shot entropic characterizations of work extraction and formation for two work-storage models, a clean battery with known equilibrium and a dirty battery with uncertain equilibrium. Both models exhibit strong asymptotic irreversibility even under arbitrarily small uncertainty. An explicit example reveals two distinct extremes: clean batteries display a bound-entanglement-like phenomenon, with positive formation cost but zero extractable work, whereas dirty batteries allow positive work extraction but require infinite formation cost. These phenomena show that equilibrium uncertainty is not a minor perturbation of the standard theory, but a structural ingredient that fundamentally reshapes the limits of quantum thermodynamics.

2602.19642 2026-06-05 cond-mat.mtrl-sci

Corrosion Evolution of T91 Steel in Static Lead-Bismuth Eutectic Under an Oxidising Environment

T91钢在静态铅铋共晶中的腐蚀演变

Minyi Zhang, Weiyue Zhou, Michael P. Short, Paul A. J. Bagot, Michael P. Moody, Felix Hofmann

AI总结 研究在氧化环境中T91钢在静态铅铋共晶中的腐蚀行为,探讨腐蚀层的形成机制及其对腐蚀速率的影响,发现保护层的形成对腐蚀过程有决定性作用。

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AI中文摘要

理解液态金属冷却核系统中的腐蚀现象对于控制其至关重要。尽管已有大量文献详细描述了结构材料在液态金属中的腐蚀速率和机理,但在新的温度、化学和杂质含量条件下仍有许多未知。我们专注于较少研究的条件,特别是研究液态铅铋共晶(LBE)在高温氧化条件下对铁素体/马氏体钢的腐蚀行为。发现腐蚀的演变由表面保护层的形成决定。没有有效保护层的区域沿马氏体晶界发生氧化,从晶间攻击过渡到更广泛的区域腐蚀。稳定的、连续的氧化层会减缓腐蚀过程,然后沿原奥氏体晶界氧化。铬和氧的扩散在这一过程中起着至关重要的作用。最令人惊讶的是,在LBE腐蚀的T91钢表面形成了一层富含铁的体心立方相,这与之前的研究报告的仅氧化物表面层相矛盾。

英文摘要

Understanding corrosion in liquid metal-cooled nuclear systems is essential in order be able to control it. While much literature exists detailing corrosion rates and mechanisms of structural materials in liquid metals, much still remains to be discovered in new regimes of temperature, chemistry, and impurity content. We focus on a less-studied set of conditions, specifically to investigate how liquid lead-bismuth eutectic (LBE) corrodes ferritic/martensitic steels under high-temperature oxidizing conditions. We find that the evolution of corrosion is determined by the formation of protection layer on the surface. The area without effective protection layer experiences oxidation along martensite grain boundaries, transitioning from intergranular attack to broader area corrosion as it progresses. The area a stable, coherent oxide scale will slow the corrosion process and then is oxidized along pre-austenite grain boundaries. Both chromium and oxygen diffusion play vital roles in this process. Most surprisingly, a layer of iron enriched body-centred cubic phase forms on the surface of LBE-corroded T91, contradicting previous studies, which reported only oxide-based surface layers.