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2606.14144 2026-06-15 cs.GT 新提交

Two Observations on Metric Distortion and Condorcet Winning Sets

关于度量失真和康多塞获胜集的两个观察

Jannik Peters

AI总结 本文连接了计算社会选择中的度量失真和无支配委员会选择,证明无支配委员会在双准则度量失真低于3时既是必要的也是充分的。

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AI中文摘要

在这篇研究笔记中,我们简要连接了计算社会选择中两个研究充分的话题:度量失真和无支配委员会的选择。特别地,我们表明无支配委员会(在某种意义上)对于实现低于$3$的双准则度量失真既是必要的也是充分的(Banishashem等人,2026)。首先,我们表明任何$\alpha$-无支配委员会,其中$\alpha \le 0.5 - \Omega(1)$,具有严格为$3 - \Omega(1)$的双准则度量失真。特别地,这意味着存在一个大小为$5$且失真最多为$2.7384$的委员会。其次,我们表明如果一个委员会具有严格为$3 - \Omega(1)$的双准则度量失真,那么它也必须是$1 - \Omega(1)$-无支配的。

英文摘要

In this research note we briefly connect two well-studied topics in computational social choice: metric distortion and the selection of undominated committees. In particular, we show that undominated committees are (in some sense) both necessary and sufficient to achieve bi-criteria metric distortion below $3$ (Banishashem et al., 2026). First, we show that any $\alpha$-undominated committee with $\alpha \le 0.5 - \Omega(1)$ has a bi-criteria metric distortion strictly of $3 - \Omega(1)$. In particular, this implies that a committee of size $5$ with distortion at most $2.7384$ exists. Secondly, we show that if a committee has a bi-criteria metric distortion strictly of $3 - \Omega(1)$, then it must also be $1 - \Omega(1)$-undominated.

2606.14143 2026-06-15 econ.EM stat.CO 新提交

Forecasting with Bayesian Panel Vector Autoregressions Using the R Package bpvars

使用R包bpvars进行贝叶斯面板向量自回归预测

Miguel Sanchez-Martinez (1), Tomasz Woźniak (2) ((1) International Labour Organization, (2) University of Melbourne)

AI总结 提出bpvars R包,通过贝叶斯层次面板VAR模型和缺失观测处理方法,实现对动态面板数据的高效预测与评估。

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AI中文摘要

R包bpvars旨在预测189个国家的就业、失业和劳动力参与率。然而,由于其建模框架的灵活性和稳健的编码,它通常适用于动态面板数据。它包括一系列贝叶斯层次面板向量自回归(VAR)模型,其特点是:(i) 国家特定的VAR模型,(ii) 其参数的先验分布以全局对应参数为中心,(iii) 具有灵活的多级层次先验分布,(iv) 包含文献中公认的基准选择的多种变体,以及(v) 四种替代规范,包括对国家特定或全局参数进行分组。一个显著的特征是基于模型一致的贝叶斯方法实现缺失观测处理。这些模型伴随贝叶斯预测,提供了广泛可能的规范,旨在提高预测精度并符合各种报告标准。我们还实现了伪样本外递归预测,以评估点预测和密度预测的性能。该包实现了模型规范、估计和预测例程,促进了简单的工作流程和可重复性,包括估计和预测结果的总结和可视化。由于采用了前沿的计量经济学和数值技术以及用C++编写的算法,它实现了非凡的计算速度。

英文摘要

The R package bpvars was designed to forecast employment, unemployment, and labour market participation rates of 189 countries. However, it is generally applicable to dynamic panel data due to the flexibility of its modelling framework and robust coding. It includes a family of Bayesian hierarchical panel Vector Autoregressions (VARs) that are characterised by: (i) country-specific VAR models (ii) with their parameters' priors centred around their global counterparts, and (iii) featuring flexible multi-level hierarchical prior distributions (iv) with many variants of well-established in the literature benchmark choices, and (v) four alternative specifications including groupping of country-specific or global parameters. A~distinguishing feature is its implementation of missing observation treatment based on a model-coherent Bayesian approach. These models are accompanied by Bayesian prediction, offering a wide range of possible specifications that aim to increase forecasting precision and comply with various reporting standards. We also implement pseudo-out-of-sample recursive forecasting for evaluating point and density forecast performance. The package implements model specification, estimation, and forecasting routines, facilitating simple workflows and reproducibility, including estimation and forecasting results summaries and visualisations. It achieves extraordinary computational speed thanks to the employment of frontier econometric and numerical techniques, as well as algorithms written in C++.

2606.14140 2026-06-15 hep-th cond-mat.stat-mech quant-ph 新提交

Quantum Entanglement of Bethe States

Bethe态的量子纠缠

Yu Hao, Yunfeng Jiang, Bi-Quan Yang, De-liang Zhong

AI总结 研究可积自旋链中Bethe态的纠缠熵,发现极值Bethe解遵循自旋依赖的量子数模式,并揭示了非紧致SL(2,R)链的独特纠缠特征。

Comments 84 pages, 16 figures

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AI中文摘要

我们研究了一族可积自旋链中Bethe态的量子纠缠,包括XXX$_{\frac{1}{2}}$模型、其高自旋推广(XXX$_s$)以及非紧致$SL(2,\mathbb{R})$链。对于壳上本征态,我们对具有周期边界条件的有限链的整个谱进行了双分纠缠熵的全面扫描,并识别了最小化和最大化纠缠的Bethe解。这些极值解在Bethe量子数中遵循系统的自旋依赖模式。在XXX$_{\frac{1}{2}}$自旋链中,对于反铁磁链,最小熵态总是与给定固定磁子扇区中的最低能量态(基态)一致。然而,对于高自旋XXX$_s$模型,最低熵态并不总是与基态相同,甚至可能是最高能量态。相比之下,最大化熵的Bethe根表现出相当复杂的结构。我们的分析进一步揭示了特殊的Bethe根构型(如奇异解和奇怪解)如何影响纠缠,并揭示了非紧致$SL(2,\mathbb{R})$链中紧致自旋链所没有的特征纠缠特性。对于壳外Bethe态,我们开发了一种优化算法,该算法在快速度分布上极值化纠缠熵,使我们能够探索在不施加Bethe ansatz方程的情况下Bethe态所能达到的最大纠缠。

英文摘要

We investigate the quantum entanglement of Bethe states across a family of integrable spin chains, including the XXX$_{\frac{1}{2}}$ model, its higher-spin generalizations (XXX$_s$), and the non-compact $SL(2,\mathbb{R})$ chain. For on-shell eigenstates, we perform a comprehensive scan of the bipartite entanglement entropy across the entire spectrum of finite chains with periodic boundary conditions, and identify the Bethe solutions that minimize and maximize the entanglement. These extremal solutions follow systematic, spin-dependent patterns in the Bethe quantum numbers. In the XXX$_{\frac{1}{2}}$ spin chain, for the antiferromagnetic chain, the state with minimal entropy always coincides with the lowest-energy state (the ground state) within a given fixed-magnon sector. For the higher-spin XXX$_s$ model, however, the lowest-entropy state is not always identical to the ground state, and can even be the state of highest energy. By contrast, the Bethe roots that maximize entropy exhibit considerably more intricate structure. Our analysis further reveals how special Bethe root configurations, such as singular and strange solutions, affect entanglement, and it uncovers characteristic entanglement features in the non-compact $SL(2,\mathbb{R})$ chain that are absent from compact spin chains. For off-shell Bethe states, we develop an optimization algorithm that extremizes the entanglement entropy over rapidity distributions, enabling us to explore the maximum entanglement achievable by a Bethe state without imposing the Bethe ansatz equations.

2606.14138 2026-06-15 physics.flu-dyn 新提交

Optimal heat transport at the edge of energy stability

能量稳定性边缘的最优热输运

Zijing Ding, Baole Wen, Hui Li

AI总结 通过边际能量稳定性理论,发现最大对流热通量出现在能量稳定性约束饱和而非湍流强度时,预测了渐近标度律,并通过数值模拟验证了无湍流的高热通量状态。

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AI中文摘要

高热通量通常与剧烈对流和湍流混合相关。这里,我们证明这种联系并非根本。利用边际能量稳定性理论,我们将近最优对流热输运识别为能量稳定性约束的饱和,而非湍流强度。该理论选择了平均温度剖面,其通量接近最佳可用最优输运状态和严格上界,预测了大瑞利数下的渐近标度$Nu\sim0.0245Ra^{1/2}$。这些剖面呈现分层结构,包括导体内层、对数律中间层和稳定分层的体区,紧密镜像最优输运计算,表明最大对流热输运出现在边际能量稳定性附近。更引人注目的是,通过预设的内部热强迫,相同的剖面可以转化为精确的传导状态。直接数值模拟显示,初始湍流随后松弛到静止状态,同时保持大的壁面热通量。因此,能量稳定性饱和既提供了输运极限的物理解释,也提供了无需湍流的高通量热传递途径。

英文摘要

Large heat flux is commonly associated with vigorous convection and turbulent mixing. Here, we show that this connection is not fundamental. Using a marginal energy-stability theory, we identify near-optimal convective heat transport with the saturation of an energy-stability constraint rather than with turbulence intensity. The theory selects mean temperature profiles whose fluxes closely approach the best available optimal transport states and rigorous upper bounds, predicting the asymptotic scaling $Nu\sim0.0245Ra^{1/2}$ at large Rayleigh number. These profiles exhibit a hierarchical structure consisting of conductive inner layers, logarithmic-like intermediate layers, and a stably stratified bulk, closely mirroring optimal transport calculations and suggesting that maximal convective heat transport emerges near marginal energy stability. More strikingly, the same profiles can be converted into exact conductive states through prescribed internal thermal forcing. Direct numerical simulations show that an initially turbulent flow then relaxes to a motionless state while maintaining a large wall heat flux. Energy-stability saturation therefore provides both a physical interpretation of transport limits and a route to high-flux heat transfer without turbulence.

2606.14137 2026-06-15 math.DG 新提交

Numerical solution of the two-dimensional Calderón problem based on the Hilbert transform of a planar domain

基于平面域希尔伯特变换的二维Calderón问题数值解

Sagar Gohri, Vladimir Sharafutdinov

AI总结 针对二维Calderón问题,利用边界DN数据等价于希尔伯特变换的性质,推导单连通域希尔伯特变换的积分公式,并基于此提出重构算法,给出数值算例。

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AI中文摘要

设$(M,g)$是$C^{\infty}$光滑紧致连通黎曼流形,边界为$\partial M$。考虑Dirichlet问题:$\Delta_gu=0,\ u|_{\partial M}=f$,其中$f\in C^{\infty}(\partial M)$。Dirichlet-to-Neumann (DN)算子$\Lambda_g:C^\infty(\partial M)\longrightarrow C^\infty(\partial M)$定义为$\Lambda_gf=\left.\frac{\partial u}{\partial\nu}\right|_{\partial M}$,其中$\nu$是边界单位外法向量,$u$是Dirichlet问题的唯一解。设$g_\partial$是由$g$诱导的$\partial M$上的黎曼度量。Calderón问题如下:$(M,g)$由数据$(\partial M,g_\partial,\Lambda_g)$确定到何种程度?在二维情形下,曲面$(M,g)$由DN数据唯一确定至共形等价。DN数据的知识等价于平面域$\Omega$的边界曲线$\Gamma=\partial\Omega$上希尔伯特变换${\mathcal H}_\Omega:C^\infty(\Gamma)\to C^\infty(\Gamma)$的知识。我们研究希尔伯特变换的性质。特别地,对于单连通域$\Omega$,我们得到了${\mathcal H}_\Omega$的一个积分公式,该公式推广了单位圆上希尔伯特变换的经典积分公式。该公式是我们从DN数据重构单连通平面域算法的基础。给出了若干数值重构结果。

英文摘要

Let $(M,g)$ be a $C^{\infty}$ smooth compact connected Riemannian manifold with boundary $\partial M$. Consider the Dirichlet problem: $\Delta_gu=0,\ u|_{\partial M}=f$ for $f\in C^{\infty}(\partial M)$. The Dirichlet-to-Neumann (DN) operator $\Lambda_g:C^\infty(\partial M)\longrightarrow C^\infty(\partial M)$ is defined by $\Lambda_gf=\left.\frac{\partial u}{\partial\nu}\right|_{\partial M}$, where $\nu$ is the unit outer normal to the boundary and $u$ is the unique solution to the Dirichlet problem. Let $g_\partial$ be the Riemannian metric on $\partial M$ induced by $g$. The Calderón problem is as follows: To what extent is $(M,g)$ determined by the data $(\partial M,g_\partial,\Lambda_g)$? In the two-dimensional case the surface $(M,g)$ is determined by the DN data uniquely up to conformal equivalence. Knowledge of the DN data is equivalent to knowledge of the Hilbert transform ${\mathcal H}_\Omega:C^\infty(\Gamma)\to C^\infty(\Gamma)$ on the boundary curve $\Gamma=\partial\Omega$ of a planar domain $\Omega$. We study properties of the Hilbert transform. In particular, we obtain an integral formula for ${\mathcal H}_\Omega$ for a simply connected $\Omega$ which generalizes the classical integral formula for the Hilbert transform on the unit circle. This formula is the base of our algorithm for reconstructing a simply connected planar domain from the DN data. Several numerical reconstructions are presented.

2606.14136 2026-06-15 eess.SY 新提交

Environment-Aware Stable Neural Koopman Dynamics Learning for Input-Driven Systems under Environmental Constraints

环境约束下输入驱动系统的环境感知稳定神经库普曼动力学学习

Lin Feng

AI总结 提出ESNKD框架,结合纤维束编码器、输入条件神经ODE、收缩合成层和LMI-ISS验证,实现环境变化下的稳定预测与安全认证。

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AI中文摘要

从测量数据构建非线性动力系统的预测模型是系统辨识与控制中长期存在的问题。尽管神经常微分方程(Neural ODEs)、库普曼算子近似和输入感知架构各自推动了该领域的发展,但没有一个能在统一的训练框架中同时处理环境变化的工作条件、严格的稳定性保证和输入到状态稳定性(ISS)认证。本文介绍了环境感知稳定神经库普曼动力学学习(ESNKD),它集成了四个组件:(i)一个束结构编码器,利用纤维束框架将环境观测映射到几何正则化的潜在流形;(ii)一个输入条件的神经ODE,其残差项处理任意外部信号,扩展了输入伴随理念;(iii)一个收缩合成层,通过Persidskii型可处理线性不等式确保收敛,类似于认证机制;(iv)一个基于LMI的ISS验证的库普曼提升阶段,遵循理论流程。理论保证包括解的存在唯一性、增量指数稳定性、具有显式增益界的ISS以及对环境扰动的鲁棒性。在五个基准系统(包括两个机器人操作平台)上的实验表明,在预测精度和安全认证率方面,该方法始终优于五个竞争基线。

英文摘要

Constructing predictive models of nonlinear dynamical systems from measurement data is a longstanding problem in systems identification and control. Although Neural ordinary differential equations~(Neural ODEs), Koopman operator approximations, and input-aware architectures have each moved the field forward, none simultaneously addresses environment-varying operating conditions, rigorous stability guarantees, and input-to-state stability (ISS) certification within a unified trainable framework. This paper introduces Environment-Aware Stable Neural Koopman Dynamics Learning (ESNKD), which integrates four components: (i)~a bundle-structured encoder that maps environmental observations to a geometrically regularized latent manifold, drawing on the fiber bundle framework; (ii)~an input-conditioned Neural ODE whose residual term handles arbitrary external signals, extending the input concomitant philosophy; (iii)~a contraction synthesis layer enforcing convergence via Persidskii-type tractable linear inequalities, analogous to the certification mechanism; and (iv)~a Koopman lifting stage with LMI-based ISS verification that follows the theoretical pipeline of. Theoretical guarantees cover solution existence and uniqueness, incremental exponential stability, ISS with explicit gain bounds, and robustness to environmental perturbation. Experiments on five benchmark systems, including two robotic manipulation platforms, show consistent improvements over five competitive baselines in both prediction accuracy and safety certification rates.

2606.14135 2026-06-15 cond-mat.quant-gas physics.atom-ph 新提交

Fermi gas of polar molecules in the Pauli-blocked regime

Pauli阻塞区域中的极性分子费米气体

Junyu Lin, Annette N. Carroll, Phillip Martin, Calder Miller, Reuben R. W. Wang, Kevin Xu, John L. Bohn, Tim de Jongh, Jun Ye

AI总结 通过偶极碰撞蒸发冷却KRb分子至费米温度以下,首次在3D和准2D几何中进入Pauli阻塞区域,并测量了Pauli抑制弹性碰撞,最终温度约为费米温度的25%。

Comments 21+26 pages, 4+11 figures

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AI中文摘要

极性分子的量子气体最近已成为探索奇异多体动力学和关联量子行为的有力平台。为了充分发挥该平台的潜力,必须在任意约束几何中制备深度简并的分子量子气体。在这里,我们利用偶极碰撞成功地在3D和准2D几何中将费米子KRb分子蒸发至远低于其费米温度。随着我们在两种几何中更深地蒸发进入简并态,我们进入了极性分子的Pauli阻塞区域,并通过测量Pauli抑制弹性碰撞首次独立证实了这一点。此外,碰撞的Pauli抑制导致我们的最终分子温度在两种几何中均限制在费米温度的大约25%,特别是在准2D蒸发中,Pauli阻塞极大地降低了原本较大的弹性与非弹性散射比。这项工作展示了在3D谐波陷阱以及单层和双层2D构型中产生极性分子简并费米气体的方法。此外,我们的工作探索了由Pauli不相容原理设定的分子费米气体蒸发的基本极限,未来可以通过引入可区分的散射伙伴来克服这一极限。

英文摘要

Quantum gases of polar molecules have recently emerged as a powerful platform for exploring exotic many-body dynamics and correlated quantum behavior. To achieve the full potential of this platform, the production of deeply degenerate quantum gases of molecules in arbitrary confinement geometries is necessary. Here, we successfully evaporate fermionic KRb molecules in both 3D and quasi-2D geometries to well below their Fermi temperatures utilizing dipolar collisions. As we evaporate deeper into degeneracy in both geometries, we enter the Pauli-blocked regime with polar molecules, which we independently confirm for the first time by measuring the Pauli suppression of elastic collisions. Moreover, the Pauli suppression of collisions contributes to the limitation of our final molecular temperature to about 25% of the Fermi temperature in both geometries, particularly limiting quasi-2D evaporation where the Pauli blockade drastically reduces an otherwise large elastic to inelastic scattering ratio. This work demonstrates the production of degenerate Fermi gases of polar molecules both in a 3D harmonic trap and in mono- and bi-layer 2D configurations. Further, our work explores the fundamental limits on evaporation of molecular Fermi gases set by the Pauli-exclusion principle, which could be overcome in the future by introducing distinguishable scattering partners.

2606.14134 2026-06-15 astro-ph.SR 新提交

Source Surface Height Optimisation for Improved Solar Wind Velocity Forecasting Across Solar Cycles 23, 24 and 25

源表面高度优化以改进太阳周期23、24和25期间的太阳风速度预测

Sandeep Kumar (1, 2), Nandita Srivastava (1), Dana-Camelia Talpeanu (3) ((1) Udaipur Solar Observatory, Physical Research Laboratory, Udaipur, 313001, India, (2) Discipline of Physics, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar-382 355, Gujarat, India (3) Solar-Terrestrial Centre of Excellence SIDC, Royal Observatory of Belgium, 1180 Brussels, Belgium)

AI总结 本研究优化势场源表面模型中的源表面高度,显著提高了Wang-Sheeley-Arge模型在L1点的太阳风速度预测性能,并发现最优高度随太阳周期相位变化。

Comments Accepted for publication in Astrophysical Journal

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AI中文摘要

势场源表面(PFSS)模型是许多最先进空间天气预测框架的基石。它包含一个单一的物理自由参数,即源表面(SS)高度。传统上,大多数研究采用固定的2.5太阳半径的SS高度。然而,一些研究使用不同的数据集和时间间隔调查了PFSS模型中的SS高度。早期的努力主要旨在改进日球层开放磁通量的估计。我们最近的研究(Kumar et al., 2025)表明,优化SS高度显著提高了Wang-Sheeley-Arge(WSA)太阳风速度预测模型在L1点的性能。该分析使用了两种类型的GONG综合磁场图,即标准(STD)和零点校正(ZPC)图,覆盖了太阳周期(SC)24和25的选定时期。在本研究中,我们使用来自地面(GONG)和空间(SDO/HMI)观测站的综合磁场图,对SC 23至25进行了全面调查。我们的结果表明,与通常采用的固定SS高度相比,优化PFSS模型中的SS高度显著提高了WSA模型的性能。我们发现,在太阳活动极小期,较高的SS高度(小于或等于2.5太阳半径)在L1点产生更好的太阳风速度预测,而在活动期则观察到相反的趋势。尽管绝对最优SS高度随SC变化,但整体分布模式保持相似。这些发现表明SS高度与SC相位在长时间尺度上存在关系。总体而言,SS高度优化增强了日球层中的背景太阳风速度预测模型。

英文摘要

The potential field source surface (PFSS) model is a cornerstone of many state-of-the-art space weather forecasting frameworks. It includes a single physical free parameter, the source surface (SS) height. Traditionally, a fixed SS height of 2.5 solar radii has been adopted in most studies. However, several studies have investigated the SS height in the PFSS model using various datasets and temporal intervals. Earlier efforts primarily aimed to improve estimates of the heliospheric open magnetic flux. Our recent study Kumar et al. (2025), showed that optimising the SS height substantially improves the performance of the Wang Sheeley Arge (WSA) solar wind speed prediction model at L1. That analysis employed two types of GONG synoptic magnetic field maps, namely standard (STD) and zero-point-corrected (ZPC) maps, over selected periods of solar cycles (SCs) 24 and 25. In this study, we perform a comprehensive investigation of SCs 23 to 25 using synoptic magnetic field maps derived from ground-based (GONG) and space-based (SDO/HMI) observatories. Our results demonstrate that optimising the SS height in the PFSS model significantly improves the WSA model performance compared to the commonly adopted fixed SS height. We find that during solar minimum, higher SS heights (less than or equal to 2.5 solar radii) yield better solar wind speed predictions at L1, whereas during active phases the opposite trend is observed. Although the absolute optimised SS height varies across SCs, the overall distribution pattern remains similar. These finding suggests a relationship between SS height and SC phase over long time scales. Overall, the SS height optimisation enhances the background solar wind speed prediction models in the heliosphere.

2606.14133 2026-06-15 cond-mat.stat-mech physics.chem-ph 新提交

Diffusion-driven autocatalytic dynamics on a sphere

球面上的扩散驱动自催化动力学

Denis S. Grebenkov

AI总结 研究粒子在球面外扩散并以催化速率复制的集体动力学,通过单粒子扩散传播子分析种群大小的统计特性,揭示长时间下的亚临界、临界和超临界相图。

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AI中文摘要

我们研究独立粒子在球面外扩散的集体动力学,这些粒子在球面上以指定的催化速率复制。在三维及以上空间维度中,扩散的瞬态性质导致自催化事件与逃逸事件之间的竞争,从而在长时间下产生亚临界(灭绝)、临界(稳态)和超临界(增长)区域之间的丰富相图。域的旋转对称性和单粒子扩散传播子的显式形式使我们能够获得种群大小(即粒子数)的统计特性。通过这种方式,我们分析了平均种群大小、其方差和高阶矩,以及完整分布。特别地,我们得到了长时间下分布的完全显式形式,并描述了向该稳态极限的缓慢幂律趋近过程。

英文摘要

We study the collective dynamics of independent particles that diffuse outside a spherical surface, on which they are replicated with a prescribed catalytic rate. In spatial dimensions three and higher, the transient nature of diffusion creates the competition between autocatalytic and escape events, thus leading to a rich phase diagram between subcritical (extinction), critical (steady-state), and supercritical (growth) regimes at long times. The rotational symmetry of the domain and an explicit form of the single-particle diffusion propagator allow us to obtain the statistics of the population size (i.e., the number of particles). In this way, we analyze the mean population size, its variance and higher-order moments, as well as the full distribution. In particular, we obtain a fully explicit form of the distribution at long times and describe a slow, power-law approach to this steady-state limit.

2606.14132 2026-06-15 stat.ME math.ST 新提交

HSCI: Neyman-Orthogonal Causal Inference under High-Dimensional Proportional Hazards

HSCI: 高维比例风险下的Neyman正交因果推断

Yingying Fan, Lan Gao, Daoji Li, Jinchi Lv

AI总结 针对生存研究中高维协变量混杂下的处理效应推断问题,提出基于Neyman近正交得分的高维生存因果推断框架,实现根n渐近正态性和一致方差估计,显著降低偏差。

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AI中文摘要

在生存研究中,当处理分配和结果受到许多基线协变量混杂时,有效的处理效应推断是基础且具有挑战性的。为此,本文提出了一个高维生存因果推断(HSCI)框架,该框架在稀疏高维Cox比例风险结果模型和高维逻辑倾向得分工作模型下提供有效的推断。为了减轻干扰估计偏差,我们开发了处理效应的Neyman近正交得分,并通过交叉拟合实现。在双重稳健干扰率条件下,我们建立了根n渐近正态性和一致方差估计。我们还将该框架扩展到高维生存协变量效应的推断。模拟示例证实,与正则化Cox估计量相比,HSCI显著减少了偏差,并在不同维度、删失和错误指定倾向模型设置下保持了有效的置信区间覆盖。对弥漫性大B细胞淋巴瘤数据的应用进一步展示了其在高维生物医学生存研究中的价值。

英文摘要

Valid treatment effect inference in survival studies is fundamental yet challenging when the treatment assignments and outcomes are confounded by many baseline covariates. To this end, in this paper we propose a high-dimensional survival causal inference (HSCI) framework that delivers valid inference under a sparse high-dimensional Cox proportional hazards outcome model and a high-dimensional logistic propensity score working model. To mitigate the nuisance estimation bias, we develop a Neyman near-orthogonal score for the treatment effect and implement it with cross-fitting. Under doubly robust nuisance-rate conditions, we establish the root-n asymptotic normality and consistent variance estimation. We also extend the framework to inference on high-dimensional survival covariate effects. Simulation examples confirm that HSCI reduces sharply the bias relative to the regularized Cox estimators and maintains valid confidence interval coverage across different dimensionality, censoring, and misspecified propensity-model settings. An application to diffuse large-B-cell lymphoma data further showcases its value for high-dimensional biomedical survival studies.

2606.14131 2026-06-15 stat.ME 新提交

G-computation for causal effect estimation from observational hierarchical data with unmeasured cluster context

G-计算用于从具有未测量聚类背景的分层观察数据中估计因果效应

Shafayet Khan Shafee, Bishal Sarker, Md. Niamul Islam Sium

AI总结 针对分层观察数据中未测量的聚类层面混杂因素和效应异质性,提出基于随机效应模型的组内G-计算方法,通过按处理流行率分组估计并聚合,有效降低偏差。

Comments 19 pages, 7 figures, 1 supplementary figure, 4 supplementary tables; supplementary material included as an appendix within the same file

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AI中文摘要

观察性研究经常涉及分层数据结构,其中个体嵌套在更高层级的单元中。在这种情况下,未测量的聚类层面因素可能会混淆处理-结果关系,并可能额外引起跨聚类的处理效应异质性,使因果效应估计复杂化。我们通过将随机效应模型(REM)作为结果模型,形式化了G-计算在分层观察数据中的应用,并提出了一种旨在减少未测量聚类背景引起的偏差的组内G-计算策略。该方法根据观察到的处理流行率对聚类进行分组,在组内执行G-计算,然后聚合组特定的估计值。通过广泛的蒙特卡洛模拟,我们使用线性模型和REM比较了标准和组内G-计算实现。结果表明,当未测量的聚类层面变量仅作为混杂因素时,基于REM的标准和组内实现均显著减少偏差;而当未测量的聚类层面因素同时作为混杂因素和处理效应异质性来源时,所提出的组内REM估计器实现了最低的RMSE。我们应用所提出的组内REM估计器,使用2019年孟加拉国MICS数据估计青少年怀孕对儿童身高-年龄Z分数的因果效应,得到估计效应为-0.12(95% bootstrap CI: [-0.18, -0.06])。所提出的组内G-计算框架为减少分层观察研究中未测量的聚类层面混杂和处理效应异质性带来的偏差提供了一种策略。

英文摘要

Observational studies frequently involve hierarchical data structures in which individuals are nested within higher-level units. In such settings, unmeasured cluster-level factors may confound the treatment-outcome relationship and may additionally induce treatment effect heterogeneity across clusters, complicating causal effect estimation. We formalize the use of g-computation for hierarchical observational data by incorporating random-effects models (REM) as outcome models and propose a within-group g-computation strategy designed to reduce bias arising from unmeasured cluster context. The approach groups clusters according to their observed treatment prevalence and performs g-computation within groups before aggregating group-specific estimates. Through extensive Monte Carlo simulations, we compare the standard and within-group implementations of g-computation using both linear models and REM. Results show that both standard and within-group REM-based implementations substantially reduce bias when the unmeasured cluster-level variable acts solely as a confounder, whereas the proposed within-group REM estimator achieves the lowest RMSE when the unmeasured cluster-level factor acts as both a confounder and a source of treatment effect heterogeneity. We apply the proposed within-group REM estimator to estimate the causal effect of adolescent pregnancy on the child height-for-age Z-score using 2019 Bangladesh MICS data, obtaining an estimated effect of -0.12 (95% bootstrap CI: [-0.18, -0.06]). The proposed within-group g-computation framework offers a strategy for reducing bias from unmeasured cluster-level confounding and treatment effect heterogeneity in hierarchical observational studies.

2606.14128 2026-06-15 cs.DS math.CO math.OC 新提交

Designing Efficient and Reachable Routes: The $k$-Step-Central Shortest Path Problem

设计高效且可达的路线:$k$-步中心最短路径问题

Johnson Phosavanh, Dmytro Matsypura

AI总结 研究在最短路径约束下最大化路径可达性的问题,提出$k$-步中心最短路径问题,证明无权重图的多项式时间可解性及有权重图的NP难性,并设计带剪枝规则的算法。

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AI中文摘要

设计快速交通路线需要平衡效率和可达性。最短路径模型确保直接、成本高效的路线,但忽略了覆盖范围;而基于中心性的方法最大化可达性,但不强制执行运营约束。我们研究选择一条最大化可达性(以路径固定距离内的节点数衡量)的最短路径的问题。为此,我们引入了$k$-步中心最短路径问题并分析其结构性质。我们证明在无权重图上最优解可以在多项式时间内找到,并提出一种带有新颖剪枝规则的算法。我们还证明当引入边权重时,问题变为NP难。此外,我们表明我们的算法可用于解决图中寻找接近中心最短路径的NP难问题。我们在多达2000个节点的合成和真实世界网络上展示了算法的效率和可扩展性。我们的结果表明,提高可达性可以替代路线扩展:增加交通线路的覆盖范围可以极大地提高其覆盖率,同时路线更短。这表明,改善可达性的主动交通基础设施投资可能比延伸主要路线更有效,为网络设计中的资源分配提供了数据驱动的基础。

英文摘要

Designing rapid transportation routes requires balancing efficiency and reachability. Shortest-path models ensure direct, cost-efficient routes but ignore coverage, while centrality-based approaches maximize accessibility but do not enforce operational constraints. We study the problem of selecting a shortest path that maximizes reachability, measured as the number of nodes within a fixed distance of the path. To do this, we introduce the $k$-Step-Central Shortest Path problem and analyse its structural properties. We show that optimal solutions on unweighted graphs can be found in polynomial time and propose an algorithm with a novel pruning rule. We also prove that the problem becomes NP-hard when edge weights are introduced. Additionally, we show that our algorithm can be used to solve the NP-hard problem of finding the closeness-central shortest path in a graph. We demonstrate the efficiency and scalability of our algorithm on synthetic and real-world networks with up to 2,000 nodes. Our results show that improving reachability can substitute for route expansion: increasing the reach of transit lines drastically increases their coverage with shorter routes. This suggests that investments in active transport infrastructure that improve reachability can be more effective than extending primary routes, providing a data-driven basis for allocating resources in network design.

2606.14126 2026-06-15 gr-qc hep-th 新提交

Refocusing of Wheeler--DeWitt wave functions at inner horizons

Wheeler-DeWitt波函数在内视界的重新聚焦

Takeshi Chiba, Keiju Murata, Daiki Saito

AI总结 通过微型超空间近似求解Wheeler-DeWitt方程,研究双视界双曲黑洞内部的量子引力效应,发现波包在内视界附近重新聚焦,表明内视界形成不受量子引力阻碍。

Comments 24 pages, 7 figures

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AI中文摘要

我们通过求解微型超空间近似下的Wheeler-DeWitt (WDW)方程,研究具有外视界和内视界的双曲黑洞内部的量子引力效应。WDW方程包含一个快子区域,其中有效势变为负值。我们开发了一种数值方法,能够一致地演化波函数穿过该区域,并在整个微型超空间中获得稳定解。对于控制量子引力效应强度的参数$\kappa$的小值,波包沿经典轨迹传播,仅有轻微的量子扩散。随着$\kappa$增加,增强的量子效应导致波包在传播过程中显著扩散。然而,当初始态局域在外视界附近时,波包在内视界附近再次变得局域。我们将这种局域性的恢复称为重新聚焦现象。这一结果表明,如果几何在外视界附近是经典的,那么在内视界附近也会再次变为经典。在微型超空间近似内,内视界的形成不受量子引力效应的阻碍。

英文摘要

We study quantum gravitational effects inside hyperbolic black holes with both outer and inner horizons by solving the Wheeler--DeWitt (WDW) equation in the minisuperspace approximation. The WDW equation contains a tachyonic region where the effective potential becomes negative. We develop a numerical method that consistently evolves the wave function across this region and obtain stable solutions throughout the entire minisuperspace. For small values of the parameter $\kappa$, which controls the strength of quantum gravitational effects, the wave packet propagates along the classical trajectory with only mild quantum spreading. As $\kappa$ increases, enhanced quantum effects lead to significant spreading of the wave packet during its propagation. Nevertheless, when the initial state is localized near the outer horizon, the wave packet becomes localized again in the vicinity of the inner horizon. We refer to this recovery of localization as a refocusing phenomenon. This result suggests that, if the geometry is classical near the outer horizon, it becomes classical again near the inner horizon. Within the minisuperspace approximation, inner-horizon formation is not obstructed by quantum gravitational effects.

2606.14124 2026-06-15 astro-ph.IM 新提交

Demonstration of a Single-chip Dual-polarization Sideband-separation SIS mixer at 2 mm Band

2 mm波段单芯片双极化边带分离SIS混频器的演示

Wenlei Shan, Shohei Ezaki, Yoshinori Uzawa

AI总结 首次在绝缘体上硅衬底上实现单片双极化边带分离SIS混频器,工作于125-163 GHz,边带抑制比超过10 dB,最低SSB噪声温度约60 K,验证了高集成度大规模外差焦平面阵列的可行性。

Comments Submitted to IEEE TST

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AI中文摘要

大规模外差焦平面阵列需要高度集成的接收架构,同时保持低噪声和足够的边带抑制,这对于毫米波段的超导SIS混频器仍然具有挑战性。在这项工作中,我们首次在绝缘体上硅衬底上演示了一种工作于2 mm波段(125-163 GHz)的单片双极化边带分离超导-绝缘体-超导(SIS)混频器。该集成SIS混频器在大部分射频范围内,在4-8 GHz中频波段实现了超过10 dB的边带抑制比,最小单边带(SSB)接收机噪声温度低至约60 K。作为混合平面集成(HPI)架构的关键构建模块,这一结果验证了高度集成的大规模外差焦平面阵列的可行性,为大幅扩展毫米波和亚毫米波射电望远镜的视场提供了一条实用途径。

英文摘要

Large-format heterodyne focal plane arrays require highly integrated receiver architectures while maintaining low noise and sufficient sideband rejection, which remains challenging for superconducting SIS mixers at millimeter wavelengths. In this work, we demonstrate, for the first time, a monolithic dual-polarization sideband-separating superconductor-insulator-superconductor (SIS) mixer operating at 2 mm wavelengths (125-163 GHz) on a silicon-on-insulator substrate. The integrated SIS mixer achieves a sideband rejection ratio exceeding 10 dB over the 4-8 GHz intermediate-frequency (IF) band across most of the radio-frequency (RF) range, with a minimum single-sideband (SSB) receiver noise temperature as low as approximately 60 K. As a key building block of the hybrid planar integration (HPI) architecture, this result verifies the feasibility of highly integrated large-format heterodyne focal plane arrays, providing a practical path toward substantially expanding the field of view of millimeter and submillimeter-wave radio telescopes.

2606.14121 2026-06-15 hep-ex hep-ph 新提交

Determining Neutrino Mass Ordering with NOvA and Upcoming JUNO Measurements

利用NOvA和即将进行的JUNO测量确定中微子质量顺序

NOvA Collaboration

AI总结 研究结合NOvA十年数据和JUNO对$|\Delta m^2_{32}|$的精确测量,发现未来五年内可实现3σ置信度下正常质量顺序的证据。

Comments 6 pages, 3 figures

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AI中文摘要

NOvA已报告利用十年数据及来自反应堆实验的外部约束确定质量顺序的显著性。JUNO合作组准备提供对$|\Delta m^2_{32}|$更精确的反应堆约束。在本信中,我们探讨了这一预期测量对NOvA确定中微子质量顺序的潜在影响。我们发现,在未来五年内,在一系列合理的JUNO测量范围内,可实现正常顺序的3σ证据。

英文摘要

NOvA has reported a significance of mass ordering determination using ten years of data together with external constraints from reactor-based experiments. The JUNO collaboration is poised to provide a more precise reactor-based constraint on $|\Delta m^2_{32}|$. In this Letter, we explore the potential impact of this anticipated measurement on the determination of the neutrino mass ordering by NOvA. We find that $3\sigma$ evidence of the normal ordering is achievable over a range of plausible JUNO measurements within the next five years.

2606.14118 2026-06-15 cond-mat.mtrl-sci 新提交

Probing Structure and Ionic Transport in Molten Lithium Carbonate

探测熔融碳酸锂中的结构与离子输运

Debsundar Dey, Abhirup Patra, Anand Narayanan Krishnamoorthy, Gopalakrishnan Sai Gautam

AI总结 采用等变图神经网络(MACE和NequIP)训练熔融淬火从头算分子动力学数据,构建熔融Li2CO3的机器学习势,MACE在能量和力预测上优于NequIP,并用于大规模模拟,揭示了Li输运由协同运动主导,且存在温度驱动的各向异性到各向同性转变。

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AI中文摘要

Li$_2$CO$_3$ (LC) 是清洁能源技术(包括高温熔融碳酸盐燃料电池、电化学碳捕获和锂基电池)的基石材料。然而,捕捉熔融状态下LC中控制结构和输运的复杂多体相互作用仍然是一个挑战,受限于从头算方法的计算成本和经典力场的精度限制。为弥补这一差距,我们部署了等变图基机器学习原子间势,具体来说,是多原子团簇展开(MACE)和神经等变原子间势(NequIP)架构,这些架构在熔融淬火从头算分子动力学数据上训练。我们的基准测试表明,与NequIP相比,MACE在预测能量和力方面提供了优越的迁移性和精度。随后,我们使用优化的MACE模型进行大规模分子动力学模拟,以探测熔融LC的性质。除了描述结构特征(例如熔融条件下C-O对关联的主导存在)外,我们的MACE模型还复现了实验测量的静态结构因子和剪切粘度值。此外,我们的模拟表明,LC中的Li输运从根本上由协同运动主导,这由远低于1(0.20-0.40)的Haven比所证实。值得注意的是,我们识别出一个温度驱动的转变:从各向异性(且高度协同)的Li输运(在1000 K时由持久的氧中心Voronoi笼支持)转变为各向同性(且协同性较低)的扩散(在1400 K时)。因此,我们提供了对熔融LC结构和输运性质的基本见解,并展示了一个用于加速设计熔盐电解质和离子液体的稳健且可扩展的框架。

英文摘要

Li$_2$CO$_3$ (LC) is a cornerstone material for clean energy technologies, including high-temperature molten carbonate fuel cells, electrochemical carbon capture, and lithium-based batteries. However, capturing the complex, many-body interactions governing the structure and transport in LC in its molten state has remained a challenge, constrained by the computational cost of \textit{ab initio} methods and the accuracy limitations of classical force fields. To address this gap, we deploy equivariant graph-based machine learned interatomic potentials, specifically, the multi atomic cluster expansion (MACE) and neural equivariant interatomic potential (NequIP) architectures that are trained on melt-quench \textit{ab initio} molecular dynamics data. Our benchmarking demonstrates that MACE provides superior transferability and precision in predicting energies and forces compared to NequIP. Subsequently, we use the optimized MACE model to perform large-scale molecular dynamics simulations to probe the properties of molten LC. Besides describing the structural features, such as the dominant presence of C-O pair correlations under molten conditions, our MACE model reproduces experimentally-measured static structure factors and shear viscosity values. Further, our simulations indicate that Li transport in LC is fundamentally dominated by concerted motion, as evidenced by Haven's ratios being significantly below unity (0.20-0.40). Notably, we identify a temperature-driven transition from anisotropic (and highly concerted) Li transport, supported by persistent oxygen-centered Voronoi cages at 1000~K, to isotropic (and less concerted) diffusion at 1400~K. Thus, we provide fundamental insights into the structural and transport properties of molten LC and also demonstrate a robust and scalable framework for the accelerated design of molten salt electrolytes and ionic liquids.

2606.14115 2026-06-15 hep-th gr-qc 新提交

Hydrodynamics of Nonminimal $F^{(a)αβ} F^{(a)γλ} R_{αγ} R_{βλ}$ AdS Black Brane

非最小耦合 $F^{(a)αβ} F^{(a)γλ} R_{αγ} R_{βλ}$ AdS 黑膜流体动力学

Mehdi Sadeghi

AI总结 通过全息对偶,研究非最小耦合项对强耦合非阿贝尔等离子体输运系数的影响,发现DC电导率和剪切粘滞熵比受耦合参数修正,并可能违反已知下界。

Comments 20 pages, no figure

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AI中文摘要

我们研究了与四维AdS黑膜对偶的强耦合非阿贝尔等离子体的流体动力学性质,其中体作用量中包含形如 $q_2 F^{(a)\alpha\beta}F^{(a)\gamma\lambda}R_{\alpha\gamma}R_{\beta\lambda}$ 的非最小耦合项。该高阶导数项引入了杨-米尔斯场强与里奇张量之间的直接相互作用,导致对最小爱因斯坦-杨-米尔斯理论的修正。利用小耦合 $q_2$ 的微扰展开,我们构建了黑膜解至一阶,并采用流体-引力对应计算了两个关键输运系数:DC色电导率 $\sigma$ 和剪切粘滞熵密度比 $\eta/s$。在全息对偶中,$\eta/s$ 与边界理论耦合常数的平方成反比,而爱因斯坦-麦克斯韦理论中的 $\sigma$ 满足普适下界 $\sigma \ge 1$(单位 $\hbar=1$),该下界在无荷黑膜时饱和,表征完美量子临界流体。我们的结果表明,非最小耦合显著改变了这些输运量。对于DC电导率,我们得到 $\sigma = 1 - q_2 \bigl(9\kappa Q^2/(L^2 r_h^4) + 7\kappa^2 Q^4/(4 r_h^8)\bigr)$,表明当 $q_2>0$ 时电导率下界被违反,而当 $q_2<0$ 时下界保持。对于剪切粘滞,我们得到 $\eta/s = (1/(4\pi))\bigl(1 + q_2\\, 7\kappa^2 Q^4/(2 r_h^8)\bigr)$,显示KSS下界被 $q_2$ 的线性项修正。$q_2$ 的符号决定了该比值是高于还是低于普适值 $1/(4\pi)$。这些发现突显了全息输运对曲率耦合规范相互作用的敏感性,并为高阶导数修正如何影响强耦合等离子体流体动力学区域提供了一个可控的实例。

英文摘要

We investigate the hydrodynamic properties of a strongly coupled non-Abelian plasma dual to a four-dimensional AdS black brane with a nonminimal coupling of the form $q_2 F^{(a)\alpha\beta}F^{(a)\gamma\lambda}R_{\alpha\gamma}R_{\beta\lambda}$ in the bulk action. This higher-derivative term introduces a direct interaction between the Yang-Mills field strength and the Ricci tensor, leading to corrections beyond the minimal Einstein-Yang-Mills theory. Using a perturbative expansion in the small coupling $q_2$, we construct the black brane solution up to first order and employ the fluid-gravity correspondence to compute two key transport coefficients: the DC color conductivity $\sigma$ and the shear viscosity to entropy density ratio $\eta/s$. In holography, $\eta/s$ is inversely proportional to the square of the coupling constant of the boundary theory, while $\sigma$ in Einstein-Maxwell theory satisfies a universal lower bound $\sigma \ge 1$ (in units where $\hbar=1$), saturated for uncharged black holes and characterizing a perfect quantum critical fluid. Our results reveal that the nonminimal coupling significantly alters these transport quantities. For the DC conductivity, we find $\sigma = 1 - q_2 \bigl(9\kappa Q^2/(L^2 r_h^4) + 7\kappa^2 Q^4/(4 r_h^8)\bigr)$, indicating a violation of the conductivity bound for $q_2>0$ while the bound is preserved for $q_2<0$. For the shear viscosity, we obtain $\eta/s = (1/(4\pi))\bigl(1 + q_2\, 7\kappa^2 Q^4/(2 r_h^8)\bigr)$, showing that the KSS bound is modified by a term linear in $q_2$. The sign of $q_2$ determines whether the ratio increases above or decreases below the universal value $1/(4\pi)$. These findings highlight the sensitivity of holographic transport to curvature-coupled gauge interactions and provide a controlled example of how higher-derivative corrections influence the hydrodynamic regime of strongly coupled plasmas.

2606.14114 2026-06-15 eess.SP 新提交

Digital Twin-Based Channel Generation Toolchain and Foundation Model for Low-Altitude XL-MIMO

基于数字孪生的低空XL-MIMO信道生成工具链与基础模型

Mengyuan Li, Yu Han, Jiachen Tian, Chao-Kai Wen, Shi Jin

AI总结 针对低空经济中XL-MIMO系统因3D移动性和近场传播导致的高保真无线数据集获取困难,提出基于数字孪生的工具链LAETwin-XL和条件去噪扩散隐式模型(CDDIM)基础模型,实现从部分信道观测中生成完整信道表示,并支持零样本外推和高效迁移学习。

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AI中文摘要

低空经济的快速发展对可靠空中通信系统的需求日益增长。超大规模多输入多输出(XL-MIMO)因其高空间分辨率和稳健连接性,成为此类系统的有前景的使能技术。然而,三维(3D)移动性加上近场传播使得获取专用的高保真无线数据集变得困难,阻碍了系统性的算法开发和评估。为解决这一问题,我们开发了LAETwin-XL,一个基于数字孪生(DT)的工具链和数据集,用于低空场景中的XL-MIMO研究。基于Sionna射线追踪(RT)模块,所提出的工具链模拟近场和远场信道,并为实际环境提供多样化的无线标签。基于该数据集,我们进一步开发了一个基于条件去噪扩散隐式模型(CDDIM)的生成式基础模型,该模型经过预训练,从不完整的信道观测中学习可迁移的XL-MIMO信道表示。与依赖于相对完整信道输入的传统任务特定模型或基础模型不同,所提出的模型能够从部分观测信道中生成性地推断出信息丰富的信道表示。实验结果表明,所提出的框架实现了有效的零样本信道外推性能。此外,使用轻量级任务头和有限的训练数据,它能够实现参数高效迁移到各种下游任务(例如信道估计、分类和定位),即使在稀疏天线观测下也能提供高精度和鲁棒性。代码和数据集可在以下网址获取:https://xxx。

英文摘要

The rapid development of the low-altitude economy (LAE) has created growing demand for reliable aerial communication systems. Extremely large-scale multiple-input multiple-output (XL-MIMO) is a promising enabler for such systems due to its high spatial resolution and robust connectivity. However, three-dimensional (3D) mobility together with near-field propagation makes it difficult to obtain dedicated high-fidelity wireless datasets, hindering systematic algorithm development and evaluation. To address this issue, we develop LAETwin-XL, a digital twin (DT)-based toolchain and dataset for XL-MIMO research in LAE scenarios. Built on the Sionna ray-tracing (RT) module, the proposed toolchain simulates near-field and far-field channels with diverse wireless labels for practical environments. Building on this dataset, we further develop a conditional denoising diffusion implicit model (CDDIM)-based generative foundation model that is pretrained to learn transferable XL-MIMO channel representations from incomplete channel observations. Unlike conventional task-specific or foundation models that rely on relatively complete channel inputs, the proposed model can generatively infer informative channel representations from partially observed channels. Experimental results demonstrate that the proposed framework achieves effective zero-shot channel extrapolation performance. Furthermore, using lightweight task heads and limited training data, it enables parameter-efficient transfer to various downstream tasks (e.g., channel estimation, classification, and localization), delivering high accuracy and robustness even under sparse antenna observations. The codes and dataset are available at this https URL.

2606.14112 2026-06-15 physics.flu-dyn 新提交

An Implicit Discrete Adjoint Gas-Kinetic Scheme for Aerodynamic Shape Optimization across all Mach Number Regimes

一种用于全马赫数气动外形优化的隐式离散伴随气体动理学格式

Hangkong Wu, Yuze Zhu, Yajun Zhu, Kun Xu

AI总结 基于气体动理学格式,结合源变换算法微分工具Tapenade和LU-SGS隐式时间推进,开发了适用于亚、跨、超、高超声速的隐式离散伴随气动优化方法。

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AI中文摘要

气体动理学格式(GKS)融合了通量差分分裂格式(FDS)和通量矢量分裂格式(FVS)的特性,在全马赫数范围内,在光滑区域提供高精度,在间断附近提供强鲁棒性。利用这些特性,开发了一种隐式离散伴随GKS,用于宽马赫数范围内的气动外形优化。伴随求解器使用基于源变换的算法微分工具Tapenade构建。为了提高计算效率,流动和伴随GKS方程均采用隐式时间推进策略,即下上对称高斯-赛德尔(LU-SGS)方法求解。通过与显式方法的比较,证明了隐式公式的有效性。为了准确施加固体壁面边界条件,特别是在高超声速区域,针对绝热无滑移和等温壁面,制定了动理学边界条件及其伴随形式。使用涵盖亚声速、跨声速、超声速和高超声速流动的四个基准测试案例,验证了所开发的基于伴随的设计优化系统的有效性。

英文摘要

The gas-kinetic scheme (GKS) integrates the characteristics of flux difference scheme (FDS) and flux vector splitting (FVS) scheme, providing high accuracy in smooth regions and strong robustness near discontinuities across all Mach regimes. Leveraging these properties, an implicit discrete adjoint GKS is developed for aerodynamic shape optimization over a wide range of Mach numbers. The adjoint solver is constructed using the source-transformation-based algorithmic differentiation tool Tapenade. To enhance computational efficiency, both the flow and adjoint GKS equations are solved using an implicit time-marching strategy, also known as the Lower-Upper Symmetric Gauss-Seidel (LU-SGS) method. The effectiveness of the implicit formulation is demonstrated through comparisons with the explicit approach. To accurately impose solid wall boundary conditions, particularly in hypersonic regimes, kinetic boundary conditions and their adjoint counterparts are formulated for both adiabatic no-slip and isothermal walls. Four benchmark test cases covering subsonic, transonic, supersonic, and hypersonic flows are used to verify the effectiveness of the developed adjoint-based design optimization system.

2606.14111 2026-06-15 physics.bio-ph q-bio.BM stat.ML 新提交

Temperature transferable Machine Learned Coarse Grained model for proteins

温度可迁移的机器学习粗粒化蛋白质模型

Jacopo Venturin, Cecilia Clementi

AI总结 提出一种热力学感知的温度可迁移MLCG框架,将粗粒化势能分解为能量和熵成分,通过精确热力学关系实现跨温度外推,在Chignolin蛋白上验证了温度依赖性的准确复现。

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AI中文摘要

粗粒化(CG)分子模拟为研究大型复杂生物系统提供了一种比全原子分子动力学更高效的替代方案。通过引入机器学习粗粒化(MLCG)模型,CG模拟的准确性得到了显著提升。然而,这些模型通常设计用于单一热力学点,缺乏温度可迁移性,无法用于预测温度依赖的量(如热容)。本文提出了一种热力学感知、温度可迁移的蛋白质MLCG框架,该框架明确地将粗粒化平均力势(PMF)分解为能量和熵成分。模型架构强制执行PMF能量与熵成分之间的精确热力学关系,并保证跨温度区间的物理一致外推和内插。我们在一个广泛的数据集上验证了该框架,该数据集涵盖了Chignolin蛋白在300 K至400 K之间五个温度下总计250微秒的分子动力学模拟,结果表明它能够复现参考全原子自由能面的温度依赖性,纠正了不感知温度的基线。此外,我们展示了可以应用一种廉价的、事后温度依赖性校正,无需重新训练MLCG势,即可准确恢复不同温度下的全原子热容。总体而言,这项工作为复杂生物分子系统的热力学可迁移MLCG模拟提供了一条物理基础路径。

英文摘要

Coarse-grained (CG) molecular simulations offer an efficient alternative to atomistic molecular dynamics to study large and complex biological systems. The accuracy of CG simulations has been increased dramatically by the introduction of machine-learned coarse-grained (MLCG) models. However, these models are typically designed to be used at a single thermodynamic point, lack temperature transferability, and can not be used to predict temperature dependent quantities like the heat capacity. Here we introduce a thermodynamically informed, temperature-transferable MLCG framework for proteins that explicitly decomposes the CG potential of mean force (PMF) into its energetic and entropic components. The model architecture enforces an exact thermodynamic relation between the energetic and entropic components of the PMF and guarantees physically consistent extrapolation and interpolation across temperature regimes. We validate this framework on an extensive dataset spanning a total of 250 $\mu$s of molecular dynamics simulations across five temperatures between 300 K and 400 K for the Chignolin protein, and demonstrate that it reproduces the temperature dependency of the reference atomistic free energy surfaces, correcting the temperature-unaware baselines. Furthermore, we show that it is possible to apply an inexpensive, post-hoc temperature-dependent correction that does not require retraining the MLCG potential, accurately recovering the atomistic heat capacity at different temperatures. Overall, this work provides a physically grounded pathway toward thermodynamically transferable MLCG simulations of complex biomolecular systems.

2606.14110 2026-06-15 math.AG 新提交

Artin-Schreier Root Stacks and lifts of group actions

Artin-Schreier 根叠与群作用的提升

Sujoy Chakraborty, Souradeep Majumder

AI总结 本文证明,当连通仿射代数群G无非平凡特征时,其在光滑射影簇上的作用可提升至相关的Artin-Schreier根叠,并证明了这类根叠上某自伴可逆层的G-线性化存在性。

Comments Comments are welcome

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AI中文摘要

设$G$是定义在正特征域上的连通仿射代数群。我们证明,当$G$无非平凡特征时,$G$在光滑射影簇上的作用可提升至其相关的Artin-Schreier根叠。还证明了在这类Artin-Schreier根叠上某自伴可逆层存在$G$-线性化。

英文摘要

Let $G$ be a connected affine algebraic group defined over a field of positive characteristic. We prove that the action of $G$ on a smooth projective variety can be lifted to its associated Artin-Schreier root stacks, whenever $G$ has no non-trivial characters. The existence of a $G$-linearization on a certain tautological invertible sheaf on such Artin-Schreier root stacks is also shown.

2606.14109 2026-06-15 astro-ph.GA astro-ph.CO 新提交

The S-PLUS Fornax Project (S+FP): Fornax-like clusters in cosmological hydrodynamical simulations

S-PLUS 天炉座项目 (S+FP):宇宙学流体动力学模拟中的天炉座类似星团

L.J. Zenocratti, A.V. Smith Castelli, M.E. De Rossi, D. Pallero, M.C. Artale, R.F. Haack, A.R. Lopes, F.R. Faifer, D. Palma, P.K. Humire, J. Thainá-Batista, W. Schoenell, T. Ribeiro, A. Kanaan, C. Mendes de Oliveira

AI总结 基于EAGLE和IllustrisTNG模拟,通过SKIRT辐射传输代码生成12波段合成测光,构建天炉座类似星团的光度目录,验证了模拟与S-PLUS观测在颜色-星等关系和空间分布上的一致性。

Comments 15 pages, 6 figures. Accepted for publication in A&A

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AI中文摘要

天炉座星系团是探索密集环境中星系演化的合适实验室。最近,南方光度局域宇宙巡天(S-PLUS)获得了天炉座前所未有的光度信息,揭示了其星系种群和周围区域的新特征。在此背景下,模拟是解释这些观测结果的过去、现在和未来的宝贵工具。我们旨在提供宇宙学背景下模拟的天炉座类似系统的稳健光度目录,以便与S-PLUS数据进行一致对比。我们分析了来自EAGLE和IllustrisTNG模拟的天炉座类似体,这些类似体是根据天炉座星系团及其中心星系NGC 1399的观测性质选择的。对于每个系统,我们使用SKIRT辐射传输代码在12个S-PLUS波段生成合成测光,再现了S-PLUS巡天的仪器配置。为我们选定的模拟天炉座类似体中的每个星系获得了模拟数据立方体、模拟图像、光谱能量分布、星等和颜色。从模拟中得出的合成测光和光谱与S-PLUS观测显示出良好的一致性。我们识别出一些与天炉座中星系空间分布具有相似性的特定系统。这些模拟候选体再现了观测到的颜色-星等关系以及星系团核心与天炉座A区域之间的空间子结构。此外,模拟星系在更大的星系团中心距离处更蓝,这与观测一致。尽管在某些情况下观测与模拟的颜色-星等图之间存在适度差异,但我们的结果支持了我们的选择标准和合成测光的适用性,以及当前宇宙学模拟再现天炉座星系团关键一般特征的可靠性。

英文摘要

The Fornax galaxy cluster constitutes a suitable laboratory to explore the evolution of galaxies in a dense environment. Recently, the Southern Photometric Local Universe Survey (S-PLUS) has obtained unprecedented photometric information of Fornax, revealing new features regarding its galaxy populations and surrounding regions. In this context, simulations are invaluable tools to interpret the past, present and fate of such observational findings. We aim to deliver a robust photometric catalog of simulated Fornax-like systems in cosmological context, to consistently contrast them with S-PLUS data. We analyze Fornax analogs from the EAGLE and IllustrisTNG simulations, selected using observed properties of the Fornax cluster and its central galaxy NGC 1399. For each system, we generated synthetic photometry in the 12 S-PLUS bands using the SKIRT radiative transfer code, reproducing the instrumental configuration of the S-PLUS survey. Simulated data cubes, mock images, spectral energy distributions, magnitudes and colors were obtained for each galaxy in our selected simulated Fornax analogs. The synthetic photometry and spectra derived from simulations show a good agreement with the S-PLUS observations. We identify particular systems which show some similarity with the spatial distribution of galaxies in Fornax. Such simulated candidates reproduce the observed color-magnitude relation and the spatial substructure between the cluster core and the Fornax A region. Also, simulated galaxies are bluer at higher cluster-centric distances, in agreement with observations. Although modest discrepancies were obtained between the observed and simulated color-magnitude diagrams in some cases, our results support the suitability of our selection criteria and synthetic photometry, and the reliability of current cosmological simulations to reproduce key general features of the Fornax cluster.

2606.14107 2026-06-15 eess.SP 新提交

Generalized Linear Graph Representation: A Compact Operator Space for Graph Signal Processing and Graph Neural Networks

广义线性图表示:用于图信号处理和图神经网络的紧致算子空间

Feiyue Zhao, Zhichao Zhang, Yangfan He

AI总结 提出广义线性图表示(GLGR),一种紧致双参数算子族,统一经典图算子与转移型算子,并基于此设计自适应卷积(AG-Conv),提升图分类与节点分类性能。

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AI中文摘要

图信号处理(GSP)和图神经网络(GNN)从根本上依赖于底层图拓扑的矩阵表示。这种表示定义了关键算子,如图傅里叶变换、谱滤波和卷积。现有的参数化算子族仅插值经典图矩阵的部分子集,而更广泛的公式在表示转移型算子时变得非紧致,限制了理论分析和稳定学习。为解决此问题,我们提出了广义线性图表示(GLGR),记为 $\mathbf{Q}_{\alpha,l}$,作为定义在有界线性域上的紧致双参数算子族。GLGR 统一了主要经典算子以及转移型算子,无需渐近参数。理论上,我们证明 $\mathbf{Q}_{\alpha,l}$ 允许一种变分分解,平衡局部平滑性和全局度加权能量,推导出谱扰动界,并建立了半正定性的图感知充分条件。基于此公式,我们开发了自适应 GLGR 卷积(AG-Conv),使传播算子本身在端到端 GNN 中可学习。在图分类和节点分类基准上的实验表明,GLGR 在多个骨干网络上改进了固定算子表示搜索和自适应图学习。

英文摘要

Graph Signal Processing (GSP) and Graph Neural Networks (GNNs) rely fundamentally on the matrix representation of the underlying graph topology. This representation defines key operators such as the graph Fourier transform, spectral filtering, and convolution. Existing parameterized operator families interpolate only partial subsets of classical graph matrices, while broader formulations become non-compact when representing transition-type operators, limiting both theoretical analysis and stable learning. To address this issue, we propose the Generalized Linear Graph Representation (GLGR), denoted by $\mathbf{Q}_{\alpha,l}$, as a compact two-parameter operator family defined on a bounded linear domain. GLGR unifies major classical operators together with transition-type operators without requiring asymptotic parameters. Theoretically, we show that $\mathbf{Q}_{\alpha,l}$ admits a variational decomposition balancing local smoothness and global degree-weighted energy, derive spectral perturbation bounds, and establish graph-aware sufficient conditions for positive semi-definiteness. Building on this formulation, we develop Adaptive GLGR Convolution (AG-Conv), which makes the propagation operator itself learnable within end-to-end GNNs. Experiments on graph classification and node classification benchmarks show that GLGR improves both fixed-operator representation search and adaptive graph learning across multiple backbones.

2606.14105 2026-06-15 hep-ex 新提交

Evidence of $ψ(3770) \to π^{0}J/ψ$

$ψ(3770) \to π^{0}J/ψ$ 的证据

BESIII Collaboration: M. Ablikim, M. N. Achasov, P. Adlarson, X. C. Ai, C. S. Akondi, R. Aliberti, A. Amoroso, Q. An, Y. H. An, M. S. Anderson, Y. Bai, O. Bakina, H. R. Bao, X. L. Bao, M. Barbagiovanni, V. Batozskaya, K. Begzsuren, N. Berger, M. Berlowski, M. B. Bertani, D. Bettoni, F. Bianchi, E. Bianco, A. Bortone, I. Boyko, R. A. Briere, A. Brueggemann, D. Cabiati, H. Cai, M. H. Cai, X. Cai, A. Calcaterra, G. F. Cao, N. Cao, S. A. Cetin, X. Y. Chai, J. F. Chang, T. T. Chang, G. R. Che, Y. Z. Che, C. H. Chen, Chao Chen, G. Chen, H. S. Chen, H. Y. Chen, M. L. Chen, S. J. Chen, S. M. Chen, T. Chen, W. Chen, X. R. Chen, X. T. Chen, X. Y. Chen, Y. B. Chen, Y. Q. Chen, Z. K. Chen, J. Cheng, L. N. Cheng, S. K. Choi, X. Chu, G. Cibinetto, F. Cossio, J. Cottee-Meldrum, H. L. Dai, J. P. Dai, X. C. Dai, A. Dbeyssi, R. E. de Boer, D. Dedovich, C. Q. Deng, Z. Y. Deng, A. Denig, I. Denisenko, M. Destefanis, F. De Mori, E. Di Fiore, X. X. Ding, Y. Ding, Y. X. Ding, J. Dong, L. Y. Dong, M. Y. Dong, X. Dong, Z. J. Dong, M. C. Du, S. X. Du, Shaoxu Du, X. L. Du, Y. Q. Du, Y. Y. Duan, Z. H. Duan, P. Egorov, G. F. Fan, J. J. Fan, Y. H. Fan, J. Fang, Jin Fang, S. S. Fang, W. X. Fang

AI总结 利用BESIII探测器在3.773 GeV收集的20.3 fb^{-1}数据,首次发现强子跃迁ψ(3770)→π^0 J/ψ,测量分支比为(2.08±0.36±0.21±0.25)×10^{-5},低于四夸克模型预测,支持介子圈效应。

Comments 10 pages, 3 figures, 2 tables

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AI中文摘要

我们利用BESIII探测器在质心能量$\sqrt{s} = 3.773$~GeV处收集的$20.3~\mathrm{fb}^{-1}$数据样本,首次报道了强子跃迁$\psi(3770) \to \pi^0 J/\psi$的证据。$e^+ e^- \to \pi^{0}J/\psi$过程以$6.1\sigma$的统计显著性被观测到,而专门归因于$\psi(3770) \to \pi^{0}J/\psi$的显著性为$4.5\sigma$。我们测量了$e^+e^- \to \pi^0 J/\psi$的 dressed 截面为$(249 \pm 44 \pm 15)~\text{fb}$,并确定了分支比$\mathcal{B}(\psi(3770) \to \pi^0 J/\psi) = (2.08 \pm 0.36 \pm 0.21\pm 0.25) \times 10^{-5}$,其中第一个不确定度为统计误差,第二个为系统误差,第三个来自与$\psi(3686) \to \pi^{0}J/\psi$衰变可能的干涉。这是该分支比的首次测定。该值显著低于四夸克模型预测,但与包含介子圈效应的计算一致,为$\psi(3770)$衰变的同位旋破坏性质提供了关键见解。

英文摘要

We report the first evidence for the hadronic transition $\psi(3770) \to \pi^0 J/\psi$ using a data sample of $20.3~\mathrm{fb}^{-1}$ collected at $\sqrt{s} = 3.773$~GeV with the BESIII detector. The $e^+ e^- \to \pi^{0}J/\psi$ process is observed with a statistical significance of $6.1\sigma$, while the significance specifically attributed to $\psi(3770) \to \pi^{0}J/\psi$ is $4.5\sigma$. We measure the dressed cross section for $e^+e^- \to \pi^0 J/\psi$ to be $(249 \pm 44 \pm 15)~\text{fb}$ and determine the branching fraction $\mathcal{B}(\psi(3770) \to \pi^0 J/\psi) = (2.08 \pm 0.36 \pm 0.21\pm 0.25) \times 10^{-5}$, where the first uncertainty is statistical, the second is systematic, and the third due to a possible interference with the $\psi(3686) \to \pi^{0}J/\psi$ decay. This is the first determination of this branching fraction. It lies significantly below tetraquark model predictions but aligns with calculations that incorporate meson loop effects, providing crucial insight into the isospin-violating nature of $\psi(3770)$ decays.

2606.14104 2026-06-15 math.AP 新提交

Symmetry breaking for the complex sine-Gordon equation

复正弦-戈登方程的对称性破缺

Shibing Chen, Changfeng Gui, Yong Liu, Jianmin Yang, Wen Yang

AI总结 研究复正弦-戈登II方程涡旋解的存在性,利用线性化方程的非平凡核构造对称性破缺解族,并证明解的稳定性和非退化性。

Comments 43 pages, 2 figures

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AI中文摘要

我们考虑复正弦-戈登II(CSG2)方程的涡旋解的存在性,该方程可视为金茨堡-朗道(GL)方程的类比。利用标准二次涡旋解 $\Psi_2$ 处线性化CSG2方程的非平凡核 $\eta_{\pm}$,我们证明它分岔出一个单参数对称性破缺解族 $\Psi_{2,\alpha}$。这些解的显式公式也可得到,由此我们为该方程提出一个新的双线性系统。我们的方法可以推广到更高次情形。还证明了1次解的非退化性和稳定性。最后,我们形式地讨论了CSG2和GL方程的多涡旋解的Lyapunov-Schmidt约化过程。

英文摘要

We consider the existence of vortex solutions to the complex sine-Gordon II (CSG2) equation, which can be viewed as an analogy of the Ginzburg-Landau (GL) equation. Using the nontrivial kernels $\eta_{\pm}$ of the linearized CSG2 equation at the standard degree-2 vortex solution $\Psi_2$, we show that it bifurcating to a one-parameter family of symmetry-breaking solutions $\Psi_{2,\alpha}$. Explicit formulas of these solutions are also available, from which we propose a new bilinear system for this equation. Our method can be generalized to higher degree case. Nondegenracy and stability of degree-1 solution are also proved. Finally, we formally discuss the Lyapunov-Schmidt reduction procedure for the multivortex solutions of the CSG2 and GL equation.

2606.14103 2026-06-15 cond-mat.supr-con 新提交

Interface-engineered oxidation-resistant wafer-level Tantalum-Tantalum thermocompression bonding for 3D integration of superconducting interconnects

用于超导互连三维集成的界面工程抗氧化晶圆级钽-钽热压键合

Harsh Mishra, Ullas Pandey, Sathish Bonam, Adirae Dinesh, Sai Rama Krishna Malladi, Shiv Govind Singh

AI总结 本研究采用超薄Au钝化层抑制Ta表面氧化,在300°C、4.93 bar下实现Ta-Ta晶圆键合,键合强度达169 MPa,为超导互连的三维集成提供低温低压热压键合策略。

Comments 6 pages, 7 figures

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AI中文摘要

超导互连的晶圆级三维集成需要与超导材料兼容的低热预算键合工艺。钽(Ta)表面快速形成原生氧化物限制了低温低压直接Ta-Ta热压键合。在本研究中,我们开发了一种使用超薄Au钝化层的抗氧化键合工艺,以抑制键合过程中的氧化物形成。工程化的界面使得在300°C、4.93 bar下实现整片Ta-Ta晶圆键合,显著降低了键合热预算和界面处α-Ta的生成,这根据文献报道可能提高相干时间。结构和界面分析证实了氧化物抑制和连续的金属键合,键合强度为169 MPa。这项工作展示了一种用于可扩展三维超导互连集成的低温低压Ta-Ta热压键合策略。

英文摘要

Wafer-level 3D integration of superconducting interconnects requires low-thermal budget bonding processes compatible with superconducting materials. Rapid native oxide formation on tantalum (Ta) surfaces limits low-temperature, low-pressure direct Ta-Ta thermocompression bonding. In this study, we develop an oxidation-resistant bonding process using an ultrathin Au passivation layer to suppress oxide formation during bonding. The engineered interface enables blanket Ta-Ta wafer bonding at 300 $^\circ$C under 4.93 bar, significantly reducing the bonding thermal budget and generation of $\alpha$-Ta across the interface, which potentially improves coherence time as reported in literature. Structural and interfacial analyses confirm oxide suppression and continuous metallic bonding, having a bond strength of 169 MPa. This work demonstrates a low-temperature, low-pressure Ta-Ta thermocompression bonding strategy for scalable 3D superconducting interconnect integration.

2606.14102 2026-06-15 math.FA 新提交

Theory and Applications of Convolution-Based short time offset linear canonical transform

基于卷积的短时偏移线性正则变换的理论与应用

Gita Rani Mahato, Manab Kundu, Alit Elsa Xavier

AI总结 提出基于卷积的短时偏移线性正则变换,建立其连续性、正交性、反演公式等基本性质,并应用于泊松求和公式、Paley-Wiener准则和采样定理,通过数值仿真验证其信号重建优势。

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AI中文摘要

本文介绍了一种基于卷积的短时偏移线性正则变换(STOLCT),并研究了其基本数学性质。具体地,我们建立了其连续性、正交关系、反演公式、值域定理和卷积定理。我们进一步探讨了STOLCT的几个重要应用,包括泊松求和公式、Paley-Wiener准则和采样定理。此外,通过数值模拟和图形分析,比较了不同场景下的信号重建性能。对STOLCT和STLCT的重建公式进行了比较研究,证明了所提出变换的有效性和潜在优势。

英文摘要

In this paper, we introduce a convolution based short time offset linear canonical transform (STOLCT) and investigate its fundamental mathematical properties. Specifically, we establish its continuity, orthogonality relations, inversion formulas, range theorem, and convolution theorem. We further explore several important applications of STOLCT, including the Poisson summation formula, the Paley Wiener criterion, and a sampling theorem. In addition, numerical simulations and graphical analyses are presented to compare signal reconstruction performance under different scenarios. A comparative study between STOLCT and STLCT is conducted with respect to their reconstruction formulas, demonstrating the effectiveness and potential advantages of the proposed transform.

2606.14101 2026-06-15 cond-mat.str-el 新提交

Altermagnetism and bond-nematicity in the spin-$1/2$ square lattice $J_1-J_2-δ$ model

自旋-$1/2$ 正方格子 $J_1-J_2-δ$ 模型中的交变磁性与键向列性

Tanja Đurić, Shenlong Yu, Pinaki Sengupta

AI总结 通过机器学习方法研究自旋-$1/2$ 正方格子 $J_1-J_2-δ$ 模型中由阻挫增强和量子涨落驱动的交变磁序熔化,发现共存对称保护拓扑价键固体和键向列序的奇特相。

Comments 13 pages, 12 figures

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AI中文摘要

我们研究了由阻挫增强和量子涨落驱动的交变磁序熔化在绝缘交变磁性材料中引起的键向列性。使用结合对称增强神经网络架构和变分蒙特卡洛的新型机器学习方法,我们考虑了自旋-$1/2$ 正方格子 $J_1-J_2-δ$ 模型,该模型已知在弱几何阻挫区域具有交变磁序,而在强阻挫和小交换相互作用调制参数 $\delta$ 区域具有无能隙自旋液相。在交换调制相对较大(导致交变磁区域中不同手性磁振子模式显著分裂)的区域,我们发现通过增加阻挫熔化交变磁序导致了一个有趣的相,该相共存对称保护拓扑价键固体和键向列序。该相的特征是磁振子对凝聚,导致键向列性、U(1) 自旋旋转和 $\mathbb{Z}_2$ 自旋反转对称性破缺,以及激发谱中三子能级的宇称分裂。尽管最近许多研究探讨了交变磁矩对交变磁性材料中各种性质(如电子能带结构和超导性)的非平凡影响,但强量子涨落的影响以及由交变磁序熔化可能产生的相却较少被探索。因此,我们的研究为识别可能在交变磁序附近出现的奇异物质相迈出了重要一步。

英文摘要

We study appearance of bond-nematicity in insulating altermagnetic materials induced by increased frustration and quantum-fluctuations driven melting of the altermagnetic order. Using novel machine learning approach that combines symmetry enhanced neural network architectures and variational Monte Carlo we consider the spin-$1/2$ square lattice $J_1-J_2-\delta$ model known to have altermagnetic ordering in the regime of small geometric frustration and a gapless spin liquid phase in the regime of strong frustration and small exchange interaction modulation parameter $\delta$. In the regime where exchange modulation is relatively large, resulting in the significant splitting of the magnon modes with different chiralities in the altermagnetic regime, we find that melting of the altermagnetic order by increased frustration leads to an intriguing phase that hosts coexisting symmetry protected topological valence bond solid and bond-nematic orders. The phase is characterized by condensation of magnon pairs that results in bond-nematicity, breaking of U(1) spin rotation and $\mathbb{Z}_2$ spin inversion symmetries and chiral splitting of the triplon-like energy levels in the excitation spectrum. Whilst numerous recent studies address non-trivial impact of altermagnetic moments on various properties in altermagnetic materials, like electronic band structure and superconductivity, influence of strong quantum fluctuations and phases that can result from melting of the altermagnetic order are much less explored. Our study therefore presents an important step in identifying exotic phases of matter that can emerge in vicinity of the altermagnetic order.

2606.14100 2026-06-15 physics.optics 新提交

Beam shifts and eigenpolarisations for the reflection of vortex beams from homogeneous magnetic surfaces

涡旋光束从均匀磁性表面反射的光束位移与本征偏振

Mairi Gilmour (1), Sarah Croke (1), Jörg B. Götte (1 and 2) ((1) University of Glasgow, (2) Max Planck Institute for the Physics of Complex Systems, Dresden)

AI总结 将涡旋光束反射理论扩展到均匀磁性表面,推导了Goos-Hänchen和Imbert-Federov位移的解析表达式,并发现了介电和磁性表面的本征偏振态。

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AI中文摘要

利用光束探测表面是一种用于材料表征的强大技术,最近,利用涡旋光束测量表面磁化强度通过使用轨道角动量光束为计量学开辟了新途径。在本文中,我们着重将单位阶涡旋光束反射的理论框架扩展到空间均匀的磁性表面,并推导了Goos-Hänchen (GH) 和 Imbert-Federov (IF) 位移的表达式。我们计算了平面波本征偏振的闭式表达式,即反射后保持相同矢量方向的偏振,对于介电表面和均匀磁性表面均适用。这些是通过将介电表面的奇异度量形式(其中相位涡旋的位置可以通过考虑有限光束宽度进行解析近似)扩展到均匀磁性表面而得到的。由此,我们找到了单位阶涡旋光束从介电表面和均匀磁性表面反射的本征偏振。我们结合GH和IF位移的琼斯矩阵解析形式,讨论了在均匀磁性表面上观察到的额外反射行为。

英文摘要

Probing surfaces with optical beams is a powerful technique utilised for material characterisation, and more recently, measuring surface magnetisation with vortex beams has opened new avenues by utilising OAM beams for metrology. In this paper, we focus on extending the theoretical framework of unit order vortex beam reflection to spatially homogeneous magnetic surfaces, and derive expressions for the Goos-Hänchen (GH) and Imbert-Federov (IF) shifts. We calculate closed form expressions for the plane wave eigenpolarisations, polarisations which remain in the same vectorial direction after reflection, for both dielectric and homogeneous magnetic surfaces. These are found by extending the singularimetry formalism for dielectric surfaces, where the position of the phase vortex can be analytically approximated by taking into account the finite beam width, to homogeneous magnetic surfaces. From this we find the eigenpolarisations of the unit order vortex beam for reflection from both dielectric and homogeneous magnetic surfaces. We discuss with relation to the analytical forms of the Jones matrices for GH and IF shifts the additional reflection behaviour observed for homogeneous magnetic surfaces.

2606.14099 2026-06-15 math.RT 新提交

Simple modules over the superconformal algebra $\mathcal{S}^{\prime}(1,n)$

超共形代数 $\mathcal{S}^{\prime}(1,n)$ 上的单模

Jinxin Hu, Rencai Lü, Xinyue Wang

AI总结 研究超共形代数 $\mathcal{S}^{\prime}(1,n)$ 上的 Shen-Larsson 模,给出其单性的充要条件及非单情况下的单子商,并利用单尖点模分类显式构造所有单尖点模。

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AI中文摘要

设 $n\geq 2$,令 $\mathcal{S}(1,n)$ 为 $\mathbb{C}[t^{\pm1}]\otimes\Lambda(n)$ 的零超散度超导子构成的李超代数。其导出代数 $\mathcal{S}^\prime(1,n):=[\mathcal{S}(1,n),\mathcal{S}(1,n)]$ 是众所周知的超共形代数。本文首先研究 $\mathcal{S}^\prime(1,n)$ 上的 Shen-Larsson 模。这些模由 G. Shen 和 T. A. Larsson 引入,由 Weyl 超代数 $K_{1,n}$ 和特殊线性李超代数 $\mathfrak{sl}(1,n)$ 的模构造而成。我们建立了 Shen-Larsson 模单性的充要条件,并研究了非单情况下的单子商。然后作为应用,基于 C. Martínez、O. Mathieu 和 E. Zelmanov 对单尖点 $\mathcal{S}^\prime(1,n)$-模的分类,我们得到了 $\mathcal{S}^\prime(1,n)$ 上所有单尖点模的显式构造。

英文摘要

Let $n\geq 2$, and let $\mathcal{S}(1,n)$ be the Lie superalgebra of zero-superdivergence superderivations of $\mathbb{C}[t^{\pm1}]\otimes\Lambda(n)$. Its derived algebra $\mathcal{S}^\prime(1,n):=[\mathcal{S}(1,n),\mathcal{S}(1,n)]$ is well known as a superconformal algebra. In this paper, we first study Shen-Larsson modules over $\mathcal{S}^\prime(1,n)$. These modules, introduced by G. Shen and T. A. Larsson, are constructed from modules over the Weyl superalgebra $K_{1,n}$ and the special linear Lie superalgebra $\mathfrak{sl}(1,n)$. We establish necessary and sufficient conditions for the simplicity of Shen-Larsson modules and investigate their simple subquotients in the non-simple case. Then as an application, building on the classification of simple cuspidal $\mathcal{S}^\prime(1,n)$-modules by C. Martínez, O. Mathieu and E. Zelmanov, we obtain an explicit construction of all simple cuspidal modules over $\mathcal{S}^\prime(1,n)$.