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2601.13963 2026-06-05 cond-mat.mtrl-sci cond-mat.mes-hall

Direct probing the quantum geometric tensor for bosonic collective excitations

直接探测玻色集体激发的量子几何张量

Chi Wu, Takashi Oka, Shuichi Murakami, Tiantian Zhang

AI总结 本文提出通过动态结构因子直接探测玻色系统量子几何张量的方法,揭示了双倍四极子-韦尔声子和节点线磁子的几何特征,并推广到多带系统,为测量玻色系统非阿贝尔量子几何提供了新途径。

Comments 8 pages, 4 figures

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AI中文摘要

量子几何张量(QGT)的实部和虚部定义了量子度量和 Berry 曲率,编码了量子态的内在几何结构。尽管电子 QGT 近年来已实验上可探测并与多种物理现象相关,其玻色子对应物仍大多未被探索。本文显示动态结构因子编码了玻色子波函数的动量空间结构,从而在整个布里渊区提供直接访问玻色子 QGT 的途径。应用此框架,我们揭示了 BaPtGe 的双倍四极子-韦尔声子和 Gd 的节点线磁子的清晰几何特征,并进一步推广到多带系统。我们的结果建立了一条测量(非)阿贝尔量子几何的新方法,为阐明其对凝聚态现象的影响提供了关键步骤。

英文摘要

The quantum geometric tensor (QGT), whose real and imaginary parts define the quantum metric and Berry curvature, encodes the intrinsic geometry of quantum states. While electronic QGT has recently become experimentally accessible and linked to diverse physical phenomena, its bosonic counterpart remains largely unexplored. Here we show that the dynamical structure factor encodes the momentum-space structure of bosonic wave functions and thereby provides direct access to the full bosonic QGT throughout the Brillouin zone. Applying this framework, we uncover clear geometric signatures in the twofold quadrupole-Weyl phonon of BaPtGe and the nodal-line magnon in Gd, and further generalize the formalism to multiband systems. Our results establish a general route to measuring (non-)Abelian quantum geometry in bosonic systems, a crucial step toward elucidating its impact on condensed matter phenomena.

2601.10903 2026-06-05 cond-mat.supr-con

Superconductivity from the Slater mode: Application to KTaO3 heterostructures

从Slater模式实现超导性:应用于KTaO3异质结构

M. R. Norman

AI总结 研究KTaO3异质结构界面2D电子气的超导性,通过软横纵光学声子模式交换解释超导机制,并讨论其超导转变温度的各向异性及BCS耦合常数的补充需求。

Journal ref Phys. Rev. B 113, 224506 (2026)

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AI中文摘要

在KTaO3与其他氧化物界面的2D电子气(2DEG)中观察到超导性,其转变温度约为其3d类比SrTiO3的十倍。超导转变温度强烈依赖于界面取向。受此观察启发,我们研究了由量子反铁电材料中软横纵光学声子模式交换引起的配对现象,并利用所得理论对这一2DEG的超导性质进行评论。我们发现(1)与实验一致的取向依赖性以及各向异性能隙函数,但(2)BCS耦合常数小于所需,因此必须通过其他声子的贡献来补充,以符合观测到的Tc值。

英文摘要

Superconductivity has been observed for the 2D electron gas (2DEG) at the interface of KTaO3 with other oxides, with a transition temperature about an order of magnitude higher than its 3d cousin SrTiO3. The superconducting transition temperature is strongly dependent on the orientation of the interface. Motivated by this observation, we study pairing due to exchange of the soft transverse optic phonon mode characteristic of quantum paraelectrics and use the resulting theory to comment on the nature of superconductivity of this 2DEG. We find (1) an orientation dependence consistent with experiment along with an anisotropic gap function, but (2) a BCS coupling constant that is smaller than needed and so must be augmented by contributions from other phonons to be consistent with the observed values of Tc.

2509.17099 2026-06-05 math.AP

Proving the existence of localized patterns and saddle node bifurcations in 1D activator-inhibitor type models

在1D激活-抑制型模型中证明局部模式和鞍点分岔存在的存在性

Dominic Blanco, Matthieu Cadiot, Daniel Fassler

AI总结 本文提出了一种通用框架,用于通过计算机辅助证明1D激活-抑制系统中静态局部解和鞍点分岔的存在性和稳定性,通过计算牛顿-康托罗维奇方法所需的显式上界来分析。

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AI中文摘要

在本文中,我们提出了一种通用框架,用于通过计算机辅助证明激活-抑制系统中静态局部1D解和鞍点分岔的存在性和稳定性。具体来说,我们开发了必要的分析来计算牛顿-康托罗维奇方法所需的显式上界。给定一个近似解ū,该方法依赖于建立一个精心选择的固定点映射在ū的邻域内是收缩的。为此,我们构造了在ū处线性化的一个近似反演,并建立了在何种条件下可以实现收缩的充分条件。这为应用计算机辅助分析来验证在ū邻域内解的存在性和局部唯一性,并控制ū处的线性化提供了框架。此外,我们扩展了该方法,通过考虑精心选择的零寻找问题,严格建立了相同类型模型中局部解的鞍点分岔。这取决于对分岔点处线性化谱的严格控制。最后,我们通过证明各种激活-抑制系统中多个稳态模式的存在性和稳定性,以及糖酵解模型中的鞍点分岔,展示了该框架的有效性。

英文摘要

In this paper, we present a general framework for constructively proving the existence and stability of stationary localized 1D solutions and saddle-node bifurcations in activator--inhibitor systems using computer-assisted proofs. Specifically, we develop the necessary analysis to compute explicit upper bounds required in a Newton--Kantorovich approach. Given an approximate solution $\bar{\mathbf{u}}$, this approach relies on establishing that a well-chosen fixed point map is contracting on a neighborhood $\bar{\mathbf{u}}$. For this matter, we construct an approximate inverse of the linearization around $\bar{\mathbf{u}}$, and establish sufficient conditions under which the contraction is achieved. This provides a framework for which computer-assisted analysis can be applied to verify the existence and local uniqueness of solutions in a vicinity of $\bar{\mathbf{u}}$, and control the linearization around $\bar{\mathbf{u}}$. Furthermore, we extend the method to rigorously establish saddle-node bifurcations of localized solutions for the same type of models, by considering a well--chosen zero--finding problem. This depends on the rigorous control of the spectrum of the linearization around the bifurcation point. Finally, we demonstrate the effectiveness of the framework by proving the existence and stability of multiple steady-state patterns in various activator--inhibitor systems, as well as a saddle--node bifurcation in the Glycolysis model.

2506.12308 2026-06-05 eess.SP cs.SY eess.SY

From Ground to Sky: Architectures, Applications, and Challenges Shaping Low-Altitude Wireless Networks

从地面到天空:塑造低空无线网络的架构、应用与挑战

Weijie Yuan, Yuanhao Cui, Jiacheng Wang, Fan Liu, Lin Zhou, Geng Sun, Tao Xiang, Jie Xu, Shi Jin, Sinem Coleri, Sumei Sun, Shiwen Mao, Abbas Jamalipour, Dong In Kim, Mohamed-Slim Alouini, Xuemin Shen

AI总结 本文介绍了一种新型低空无线网络(LAWN),其是一种可重构的三维分层架构,通过整合空中和地面节点的连接、传感、控制和计算功能,在复杂动态和关键任务环境中实现无缝操作,同时探讨了集成感知与通信(ISAC)、语义通信和全驱动控制系统等关键技术,并识别了潜在应用和关键跨层挑战。

Comments 12 pages

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AI中文摘要

在本文中,我们介绍了一种新型低空无线网络(LAWN),其是一种可重构的三维(3D)分层架构。特别是,LAWN在空中和地面节点中整合了连接、传感、控制和计算功能,以在复杂、动态和关键任务环境中实现无缝操作。与传统的空中通信系统不同,LAWN的显著特点是其功能平面的紧密集成,其中多种功能持续重塑自身以在低空天空中安全高效地运行。通过LAWN,我们讨论了几种关键技术,如集成感知与通信(ISAC)、语义通信和全驱动控制系统。最后,我们确定了潜在的应用和关键跨层挑战。本文为未来低空空域的研究和开发提供了全面的路线图。

英文摘要

In this article, we introduce a novel low-altitude wireless network (LAWN), which is a reconfigurable, three-dimensional (3D) layered architecture. In particular, the LAWN integrates connectivity, sensing, control, and computing across aerial and terrestrial nodes that enable seamless operation in complex, dynamic, and mission-critical environments. Different from the conventional aerial communication systems, LAWN's distinctive feature is its tight integration of functional planes in which multiple functionalities continually reshape themselves to operate safely and efficiently in the low-altitude sky. With the LAWN, we discuss several enabling technologies, such as integrated sensing and communication (ISAC), semantic communication, and fully-actuated control systems. Finally, we identify potential applications and key cross-layer challenges. This article offers a comprehensive roadmap for future research and development in the low-altitude airspace.

2601.09664 2026-06-05 gr-qc astro-ph.CO hep-ph

Constant-roll $β$-exponential inflation: Palatini formalism

常-roll β-指数膨胀:Palatini形式主义

Ozan Sargın

AI总结 本文研究了在非最小耦合二次(R+R²)引力框架下,β-指数势模型的膨胀动力学。通过Palatini形式主义推导出有效的Einstein框架广义k膨胀理论,并在常-roll条件下分析其演化。通过参数空间的全面扫描,获得谱指数n_s和张量-标量比r的预测。结果表明,在特定可行的参数范围内,膨胀观测值与ACT DR6和Planck任务的最新观测数据高度一致,从而确定了参数空间的物理一致区域。此外,原始非高斯性评估证实了常-roll动力学生成了可观测的可行现象学特征。

Comments 26 pages, 5 figures

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AI中文摘要

本文研究了在非最小耦合二次(R+R²)引力框架下,β-指数势模型的膨胀动力学。所采用的势函数形式提供了合理的框架;其物理起源可以被解释为确定额外维度大小的radion场的稳定动力学,或者作为从Tsallis非广泛热力学中自然出现的q-指数函数的表现。利用Palatini形式主义,我们推导出一个有效的Einstein框架广义k膨胀理论,并在常-roll条件下分析其演化。我们对参数空间进行了全面扫描,以获得谱指数n_s和张量-标量比r的预测。我们的结果表明,对于特定可行的模型参数范围,膨胀观测值与ACT DR6和Planck任务的最新观测数据高度一致,从而确定了参数空间的物理一致区域。此外,原始非高斯性评估证实了常-roll动力学生成了可观测的可行现象学特征。

英文摘要

This paper investigates the inflationary dynamics of a $β$-exponential potential model within the framework of non-minimally coupled quadratic $(R+R^2)$ gravity. The functional form of the adopted potential provides a well-motivated framework; its physical origin can be interpreted either as the stabilization dynamics of a radion field determining the size of the extra dimension in braneworld cosmology, or as a manifestation of the $q$-exponential function emerging naturally from Tsallis non-extensive thermodynamics. Utilizing the Palatini formalism, we derive an effective Einstein-frame generalized k-inflation theory and analyze its evolution under the constant-roll condition. We perform a comprehensive scan of the parameter space to obtain predictions for the spectral index $n_s$ and the tensor-to-scalar ratio $r$. Our results demonstrate that for specific viable ranges of the model parameters, the inflationary observables are in excellent agreement with the latest observational data from the Atacama Cosmology Telescope (ACT) DR6 and the Planck mission, thereby identifying the physically consistent regions of the parameter space. Furthermore, an evaluation of the primordial non-Gaussianity confirms that the constant-roll dynamics generate a distinct, observationally viable phenomenological signature.

2409.14933 2026-06-05 math.NT

Adjoint $L$-functions, congruence ideals, and Selmer groups over $\mathrm{GL}_n$

伴随 $L$-函数、同余理想与 $\mathrm{GL}_n$ 上的 Selmer 组

Ho Leung Fong

AI总结 本文研究了伴随 $L$-函数与 $\mathrm{GL}_n$ 上同余理想之间的关系,并利用此结果探讨了自守形式的同余与伴随 $L$-函数之间的联系,特别地,在 CM 和完全实数域中,给出了某些 Selmer 组大小的下界。

Comments 38 pages. Many corrections and improvements. The major changes are Lemma 4.5, Corollary 4.10, Theorem 4.26

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AI中文摘要

在本文中,我们研究了 $L(1,π,\mathrm{Ad}^\circ)$ 与 $\mathrm{GL}_n$ 上任何数域上的同调 cuspidal 自守表示 $π$ 的同余理想之间的关系。然后我们利用此结果,推导出自守形式的同余与伴随 $L$-函数之间的关系。对于 CM 和完全实数域,我们应用此结果,得到某些 Selmer 组大小的下界,该下界以 $L(1,π,\mathrm{Ad}^\circ)$ 表示。

英文摘要

In this paper, we relate $L(1,π,\mathrm{Ad}^\circ)$ to the congruence ideals for cohomological cuspidal automorphic representations $π$ of $\mathrm{GL}_n$ over any number field. We then use this result to deduce relationships between the congruences of automorphic forms and adjoint $L$-functions. For CM and totally real fields, we apply the result to obtain a lower bound on the cardinality of certain Selmer groups in terms of $L(1,π,\mathrm{Ad}^\circ)$.

2601.09023 2026-06-05 hep-ph hep-ex

Searching for Quirks at LHCb

在LHCb寻找 quirks

Xabier Cid Vidal, Miguel Fernández Gómez, Matthew Low, Alejandro Novo Cal, Yuhsin Tsai, Carlos Vázquez Sierra

AI总结 本文提出利用LHCb顶点定位器(VELO)的前向几何和软件触发机制,通过检测quirk对产生的特征反向平面击中模式,探索quirk参数空间中的新区域,为发现quirk提供了一种有力的互补方法。

Comments 12 pages, 4 figures

Journal ref J. High Energ. Phys. 2026, 37 (2026)

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AI中文摘要

Quirks是通过隐藏束缚力的磁通管连接的重粒子,其在参数空间的大部分区域中仍处于弱约束状态。这种磁通管起到一根弦的作用,在足够短的距离内,当quirk对分离时会伸展,然后将对拉回,导致有趣的动态。我们提出了一种新颖的搜索方法,利用LHCb顶点定位器(VELO)的前向几何和软件触发机制,其独特适合检测quirk对产生的特征反向平面击中模式,这种模式由少量横向反冲产生。通过详细模拟VELO几何结构,结合简单的几何选择,我们提出了不同的灵敏度投影,证明LHCb可以探测现有ATLAS和CMS搜索无法触及的参数区域,为发现quirk提供了一种有力的互补路径。

英文摘要

Quirks are heavy particles connected by a flux tube from a hidden confining force that remain weakly constrained in large regions of their parameter space. This flux tube acts as a string that, at short enough distance, stretches as the quirk pair separates, then pulls the pair back together leading to interesting dynamics. We propose a novel search using the LHCb Vertex Locator (VELO), whose forward geometry and software-based trigger are uniquely suited to detecting the characteristic back-to-back, planar hit patterns produced by quirk pairs with little transverse recoil. Using detailed simulations of the VELO geometry, together with simple geometric selections, we present different sensitivity projections, demonstrating that LHCb can probe parameter regions inaccessible to existing ATLAS and CMS searches and offering a powerful, complementary path toward discovering quirks.

2601.07734 2026-06-05 gr-qc astro-ph.HE astro-ph.SR

Rotation-dependent $I$-Love-$Q$-$δM$ relations in perturbation theory

依赖旋转的 perturbation theory 中的 I-Love-Q-δM 关系

Eneko Aranguren

AI总结 本文基于 perturbation theory,研究了 I-Love-Q-δM 关系在不同旋转条件下的应用,提出了不依赖静态质量的归一化量,从而扩展了这些关系的应用范围。

Comments Published version. Two glossaries (Tables V-VI) and a flowchart (Fig 5) have been included to help the reader with the notation

Journal ref Phys. Rev. D 113, 104076 (2026)

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AI中文摘要

所谓的 I-Love-Q 关系将恒星的归一化惯性矩、Love 数和四极矩联系起来。这些关系原则上允许在已知第三个量的情况下推断出另外两个量。然而,它们的应用受到限制,因为归一化多极矩依赖于由 Tolman-Oppenheimer-Volkoff 方程得出的静态质量,而该质量不能直接观测。在本工作中,利用 perturbation theory,我们发现 I-Love-Q 关系也可以用不依赖静态质量,而依赖实际(可观测)质量的另一种归一化量来表述。

英文摘要

The so-called $I$-Love-$Q$ relations link some normalized versions of the moment of inertia, the Love number, and the quadrupole moment of a star. These relations, in principle, enable the inference of two of the quantities given the third. However, their use has been limited because the normalized versions of the multipole moments rely on the static mass derived from the Tolman-Oppenheimer-Volkoff equation, which is not directly observable. In this work, using perturbation theory, we find that the $I$-Love-$Q$ relations can also be formulated in terms of an alternative set of normalized quantities that do not depend on the static mass, but on the actual (observable) mass.

2601.06655 2026-06-05 cs.CE physics.comp-ph stat.ML

Physics-constrained Gaussian Processes for Predicting Shockwave Hugoniot Curves

具有物理约束的高斯过程用于预测冲击波赫荣尼特曲线

George D. Pasparakis, Himanshu Sharma, Rushik Desai, Chunyu Li, Alejandro Strachan, Lori Graham-Brady, Michael D. Shields

AI总结 本文提出了一种基于物理约束的高斯过程回归框架,利用少量冲击波模拟数据预测受冲击材料状态及其不确定性沿赫荣尼特曲线的演变,通过约束Rankine-Hugoniot跃变条件构建热力学一致的协方差函数,从而在少量可解释超参数上进行优化,识别从领先弹性波到滞后塑性及相变波的转变。

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AI中文摘要

本文开发了一种受物理约束的高斯过程回归框架,用于利用少量冲击波模拟数据预测受冲击材料状态及其相关不确定性沿赫荣尼特曲线。所提出的高斯过程通过约束不同受冲击材料状态之间的Rankine-Hugoniot跃变条件来构建热力学一致的协方差函数。这导致在少量可解释超参数上进行优化的问题,从而能够识别从领先弹性波到滞后塑性及相变波的转变。赫荣尼特曲线是理解材料在极端条件下行为的重要指标,包括用于开发状态方程和确定材料性质如赫荣尼特弹性极限,但通过大规模分子动力学模拟或冲击实验生成这些曲线成本很高。在这些约束下,所提出的方法利用有限数量的分子动力学模拟生成赫荣尼特曲线。我们考虑碳化硅作为代表性材料,并使用反向弹道方法进行分子动力学模拟。该框架能够以令人满意的精度重现赫荣尼特曲线,同时利用高斯过程后验量化预测的不确定性。这些不确定的赫荣尼特预测可用于校准状态方程模型、估计材料性质或指导未来的实验和/或模拟活动。

英文摘要

A physics-constrained Gaussian Process regression framework is developed for predicting shocked material states and their associated uncertainties along the Hugoniot curve using data from a small number of shockwave simulations. The proposed Gaussian process is constrained by the Rankine-Hugoniot jump conditions between the various shocked material states to construct a thermodynamically consistent covariance function. This leads to the formulation of an optimization problem over a small number of interpretable hyperparameters and enables the identification of regime transitions, from a leading elastic wave to trailing plastic and phase transformation waves. Shock Hugoniots are an important measure for understanding material behavior under extreme conditions, including for the development of equations of state and determining material properties such as the Hugoniot Elastic Limit, but they are costly to generate through large-scale molecular dynamics simulations or shock experiments. Under these constraints, the proposed methodology establishes Hugoniot curves from a limited number of molecular dynamics simulations. We consider silicon carbide as a representative material and Molecular Dynamics simulations are performed using a reverse ballistic approach. The framework reproduces the Hugoniot curve with satisfactory accuracy while also quantifying the uncertainty in the predictions using the Gaussian Process posterior. These uncertain Hugoniot predictions can then be used to calibrate equation of state models, estimate material properties, or inform future experimental and/or simulation campaigns.

2411.08713 2026-06-05 math.AP math.FA

An existence result in annular regions times conical shells and its application to nonlinear Poisson systems

环形区域与锥形壳体中的存在性结果及其在非线性泊松系统中的应用

Gennaro Infante, Giovanni Mascali, Jorge Rodríguez-López

AI总结 本文通过拓扑方法在规范空间中提出了一种新的非线性算子系统的存在性结果,解决方案位于环形区域与锥形壳体的乘积中,并将其应用于带有齐次狄利克雷边界条件的非线性泊松方程系统,证明了所有分量非平凡的解的存在性和局部化,还给出了一个具体的例子和数值近似解,最后将结果应用于具有源项的竞争物种反应-扩散洛特卡-沃勒茨系统。

Comments 21 pages, 4 figures

Journal ref Annali di Matematica (2026)

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AI中文摘要

我们通过拓扑方法为规范空间中的抽象非线性算子系统提供了一种新的存在性结果。解位于环形区域与锥形壳体的乘积中。该理论结果具有广泛的应用范围,为了具体说明,我们将其应用于具有齐次狄利克雷边界条件的非线性泊松方程系统。对于后者问题,我们得到了所有分量非平凡的解的存在性和局部化。这还通过一个具体的例子加以说明,其中我们还提供了数值近似解,与理论结果一致。最后,我们将我们的结果应用于具有源项的竞争物种反应-扩散洛特卡-沃勒茨系统。

英文摘要

We provide a new existence result for abstract nonlinear operator systems in normed spaces, by means of topological methods. The solution is located within the product of annular regions and conical shells. The theoretical result possesses a wide range of applicability, which, for concreteness, we illustrate in the context of systems of nonlinear Poisson equations subject to homogeneous Dirichlet boundary conditions. For the latter problem we obtain existence and localization of solutions having all components nontrivial. This is also illustrated with an explicit example in which we also furnish a numerically approximated solution, consistent with the theoretical results. We conclude with an application of our results to a reaction--diffusion Lotka--Volterra system with source terms for competing species.

2503.21207 2026-06-05 astro-ph.CO hep-ph

AliCPT Sensitivity to Cosmic Reheating

AliCPT 对宇宙再加热的灵敏度

Yang Liu, Lei Ming, Marco Drewes, Hong Li

AI总结 本文基于AliCPT探测原始引力波的能力,评估其对宇宙膨胀后再加热时期的灵敏度,通过三种膨胀模型(α-吸引子T模型、RGI膨胀和QCD驱动的温暖膨胀)分析,发现AliCPT-1结合普朗克卫星可将再加热温度测量精度控制在10%以内,为QCD驱动温暖膨胀中的胶子耦合提供约束。

Comments 14 pages, 9 figures. Revised version with a more realistic AliCPT-1 sensitivity forecast, extended to three inflationary models, and an expanded discussion of knowledge gain and model testability

Journal ref Phys.Rev.D 113 (2026) 10, 103507

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AI中文摘要

我们基于Ali宇宙微波背景偏振望远镜(AliCPT)探测原始引力波的能力,首次评估其对宇宙膨胀后再加热时期的灵敏度。我们考虑了三种膨胀模型,即α-吸引子T模型、RGI膨胀和QCD驱动的温暖膨胀。假设一个基准值r=0.01,我们发现AliCPT-1在其完全加载的焦点平面探测器配置下,结合普朗克卫星,可以将再加热温度的测量精度控制在10%以内。对于QCD驱动的温暖膨胀,这可以转化为对膨胀子与胶子耦合的约束,该耦合可以独立通过轴子搜索实验探测。我们的结果构成了首次展示AliCPT探测热大爆炸初始温度和连接宇宙膨胀与粒子物理的微观参数的能力。

英文摘要

We present the first assessment of the Ali Cosmic Microwave Background Polarization Telescope's (AliCPT) sensitivity to the reheating epoch after cosmic inflation, based on its ability to detect primordial gravitational waves. We consider three models of inflation, an $α$-attractor T-model, RGI inflation and QCD-driven warm inflation. Assuming a fiducial value of $r=0.01$, we find that AliCPT-1, in its fully loaded focal plane detector configuration and combined with Planck, can provide measurements of the order of magnitude of the reheating temperature with an accuracy around $10\%$. For QCD-driven warm inflation this can be translated into a constraint on the inflaton coupling to gluons, which can be probed independently in axion search experiments. Our results constitute the first demonstration of AliCPT's ability to probe the initial temperature of the hot big bang and the microphysical parameter connecting cosmic inflation and particle physics.

2601.02416 2026-06-05 gr-qc astro-ph.CO hep-th

Primordial Black Hole Formation in $f(R)=R+αR^2$ Gravity: Perturbative and Non-Perturbative Analysis

$f(R)=R+αR^2$引力理论中原始黑洞形成:微扰和非微扰分析

G. G. L. Nashed, A. Eid

AI总结 本文研究了$ f(R)=R+αR^2 $引力模型中引力坍缩和原始黑洞(PBH)形成的机制,通过微扰和半微扰分析探讨了PBH形成阈值$ δ_c $的变化趋势及非线性效应的重要性。

Comments 18 pages, two Figs. and one table, In press Eur. Phys. J. C

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AI中文摘要

我们对$ f(R)=R+αR^2 $模型中的引力坍缩和原始黑洞形成进行了完整的解析和半解析研究。首先,我们推导了围绕广义相对论(GR)的微扰展开,到小参数$ α $的一阶。对于塌缩的平坦FLRW尘埃内部,我们计算了标度因子、恒星半径和视界形成时间的一阶修正。然后利用这些结果推断PBH形成阈值$ δ_c $的变化趋势,而非直接定量确定。在这一微扰框架中,二次修正在第一阶改变了尘埃坍缩的动力学,而平坦辐射主导背景在同一阶未受到非平凡修正。因此,辐射时代中PBH形成的任何修改必须来自非线性或非微扰效应。微扰分析因此提供了关于曲率修正如何影响坍缩的定性见解,特别是在高曲率区域。为了进入这一区域,我们将理论重新表述为爱因斯坦框架,其中模型变为广义相对论加上具有Starobinsky势的标量场$ ϕ $。我们提供了支配宇宙背景和过密封闭FLRW区域演化的完整ODE系统。该系统可以数值积分以获得PBH形成临界过密度$ δ_c(k) $,在膨胀结束时。

英文摘要

We present a complete analytic and semi-analytic study of gravitational collapse and primordial black hole (PBH) formation in the quadratic $f(R)$ model $f(R)=R+αR^2$. We first derive the perturbative expansion around General Relativity (GR), working to first order in the small parameter $α$. For a collapsing flat FLRW dust interior we compute the explicit first-order corrections to the scale factor, the stellar radius, and the horizon formation time. { We then use these results to infer the expected trend in the PBH formation threshold $δ_c$, rather than a direct quantitative determination. Within this perturbative framework, the quadratic correction modifies the dust collapse dynamics at first order, while the flat radiation-dominated background does not receive a nontrivial correction at the same order. As result, any modification of PBH formation in the radiation era must arise from nonlinear or non-perturbative effects. The perturbative analysis therefore provides qualitative insight into how curvature corrections influence collapse, particularly in high-curvature regimes.} To access this regime we reformulate the theory in the Einstein frame, where the model becomes GR plus the scalaron field $ϕ$ with the Starobinsky potential. We provide the complete ODE system governing both the cosmological background and the evolution of an overdense closed FLRW patch. This system can be numerically integrated to obtain the critical overdensity $δ_c(k)$ for PBH formation near the end of inflation.

2601.00952 2026-06-05 hep-th astro-ph.CO hep-ph

On Cosmological Correlators at One Loop

在一阶环上研究宇宙相关子

Guilherme L. Pimentel, Tom Westerdijk

AI总结 本文研究了平直空间中无质量标量场的一阶环等时相关子,通过时间有序分解和宇宙类比的Baikov表示,系统地构造了相对简单的环积分,并阐明了在该设定下,相关子的环修正比波函数系数的更简单。作为基准例子,分析了气泡和三角图。气泡表现出UV发散,可通过局部反常项消除,而三角图给出有限结果,通过拉普拉斯格林函数的积分变换用双对数函数显式计算。通过兰道分析分类这些图的动量奇异行为,识别了新型奇异行为,并通过显式结果验证分析。最后,推导了一阶宇宙相关子在奇异动量学下的因子化性质,将其与平直空间环振幅和低点树级相关子联系起来。

Comments 77 pages, 32 figures

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AI中文摘要

我们研究了平直空间中无质量标量场的一阶环等时in-in相关子。利用相关子的时间有序分解以及宇宙类比的Baikov表示,我们系统地构造了相对简单的环积分,并阐明了在该设定下,相关子的环修正比波函数系数的更简单。作为基准例子,我们分析了气泡和三角图。气泡表现出UV发散,可通过局部反常项消除,而三角图给出有限结果,我们通过拉普拉斯格林函数的积分变换显式地用双对数函数计算。我们通过兰道分析分类这些图的动量奇异行为,识别了新型奇异行为,并通过显式结果验证分析。最后,我们推导了一阶宇宙相关子在奇异动量学下的因子化性质,将其与平直空间环振幅和低点树级相关子联系起来。

英文摘要

We study equal-time in-in correlators of massless scalar fields in flat space at one loop. Using the time-ordered decomposition of correlators together with a cosmological analogue of the Baikov representation, we systematically construct relatively simple loop integrals and make manifest why, in this setting, loop corrections to correlators are simpler than those of wavefunction coefficients. As benchmark examples, we analyse the bubble and triangle diagrams. The bubble exhibits a UV divergence that can be removed by a local counterterm, while the triangle yields a finite result, which we evaluate explicitly in terms of dilogarithms using an integral transform for the Laplacian Green's function. We classify the kinematic singularities of these diagrams using Landau analysis, identifying novel types of singular behaviour, and validate this analysis against the explicit results. Finally, we derive a factorisation property of one-loop cosmological correlators at singular kinematics, relating them to flat-space loop amplitudes and lower-point tree-level correlators.

2601.00618 2026-06-05 q-bio.QM q-bio.BM

Quantifying the uncertainty of molecular dynamics simulations : Good-Turing statistics revisited

分子动力学模拟不确定性的量化:Good-Turing统计学的重新审视

Vasiliki Tsampazi, Nicholas M. Glykos

AI总结 该研究提出了一种改进的Good-Turing算法,用于高效估计分子动力学模拟中完全新结构出现的概率,适用于超长模拟。

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AI中文摘要

我们之前已展示Good-Turing统计学可应用于分子动力学轨迹以估计完全新(迄今为止未观察到)生物分子结构出现的概率,并证明该方法稳定可靠且预测可验证。初始算法的主要问题是需要计算并存储当前可用轨迹的二维RMSD矩阵,这限制了该方法在超长模拟中的应用。在此,我们描述了一种新的Good-Turing算法变体,其内存需求与轨迹中的结构数量成线性关系,使其适用于极长模拟。我们证明新方法与旧实现结果几乎相同,并展示了包含多达2200万结构的轨迹结果。实现新算法的计算机程序可在标准存储库中获得。

英文摘要

We have previously shown that Good-Turing statistics can be applied to molecular dynamics trajectories to estimate the probability of observing completely new (thus far unobserved) biomolecular structures, and showed that the method is stable, dependable and its predictions verifiable. The major problem with that initial algorithm was the requirement for calculating and storing in memory the two-dimensional RMSD matrix of the currently available trajectory. This requirement precluded the application of the method to very long simulations. Here we describe a new variant of the Good-Turing algorithm whose memory requirements scale linearly with the number of structures in the trajectory, making it suitable even for extremely long simulations. We show that the new method gives essentially identical results with the older implementation, and present results obtained from trajectories containing up to 22 million structures. A computer program implementing the new algorithm is available from standard repositories.

2512.22133 2026-06-05 math.RA math.AC

A Course in Ring Theory

环论课程

David Krumm

AI总结 本书系统介绍了环论的核心概念和方法,重点在于结构理解而非百科全书式的覆盖,涵盖了欧几里得环、主理想环、唯一分解环、中国剩余定理以及多项式环的结构。

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AI中文摘要

本书是一本严谨且以概念为导向的环论入门教材。强调结构理解而非百科全书式的覆盖:通过理想、同态、商环和普遍属性来研究环,系统关注因式分解和多项式环。核心主题包括欧几里得环、主理想环、唯一分解环、中国剩余定理以及多项式环的结构。阐述基于证明,并刻意控制节奏,包含复习章节以巩固核心思想并包含选定的解答,以及设计以强化概念洞察力的练习。

英文摘要

This book is a rigorous and conceptually oriented introduction to ring theory. The emphasis is on structural understanding rather than encyclopedic coverage: rings are studied through ideals, homomorphisms, quotients, and universal properties, with systematic attention to factorization and polynomial rings. Core topics include Euclidean domains, principal ideal domains, unique factorization domains, the Chinese Remainder Theorem, and the structure of polynomial rings. The exposition is proof-based and deliberately paced, with review chapters that consolidate core ideas and include selected worked solutions, and with exercises designed to reinforce conceptual insight.

2512.19887 2026-06-05 hep-ex

Measurement of the solar neutrino interaction rate below 3.49 MeV in Super-Kamiokande-IV

在超日核四号中测量低于3.49 MeV的太阳中微子相互作用率

Kamiokande Collaboration, A. Yankelevich, K. Abe, Y. Asaoka, M. Harada, Y. Hayato, K. Hiraide, T. H. Hung, K. Hosokawa, K. Ieki, M. Ikeda, J. Kameda, Y. Kanemura, Y. Kataoka, S. Miki, S. Mine, M. Miura, S. Moriyama, K. Nakagiri, M. Nakahata, S. Nakayama, Y. Noguchi, G. Pronost, K. Sato, H. Sekiya, R. Shinoda, M. Shiozawa, Y. Suzuki, A. Takeda, Y. Takemoto, H. Tanaka, T. Yano, S. Chen, Y. Itow, T. Kajita, R. Nishijima, K. Okumura, T. Tashiro, T. Tomiya, X. Wang, F. J. de Garay Arcones, P. Fernandez, L. Labarga, D. Samudio, B. Zaldivar, C. Yanagisawa, B. Jargowsky, E. Kearns, J. Mirabito, L. Wan, T. Wester, B. W. Pointon, J. Bian, B. Cortez, N. J. Griskevich, Y. Jiang, M. B. Smy, H. W. Sobel, V. Takhistov, J. Hill, M. C. Jang, S. H. Lee, D. H. Moon, R. G. Park, B. S. Yang, B. Bodur, K. Scholberg, C. W. Walter, A. Beauchene, O. Drapier, A. Ershova, M. Ferey, E. Le Blevec, Th. A. Mueller, P. Paganini, C. Quach, R. Rogly, T. Nakamura, J. S. Jang, R. P. Litchfield, L. N. Machado, F. J. P. Soler, J. G. Learned, K. Choi, S. Cao, L. H. V. Anthony, N. W. Prouse, M. Scott, Y. Uchida, V. Berardi, N. F. Calabria, M. G. Catanesi, N. Ospina, E. Radicioni, A. Langella, G. De Rosa, G. Collazuol, M. Feltre, M. Mattiazzi, L. Ludovici, M. Gonin, L. Perisse, B. Quilain, S. Horiuchi, A. Kawabata, M. Kobayashi, Y. M. Liu, Y. Maekawa, Y. Nishimura, R. Akutsu, M. Friend, T. Hasegawa, Y. Hino, T. Ishida, T. Kobayashi, M. Jakkapu, T. Matsubara, T. Nakadaira, Y. Oyama, A. Portocarrero Yrey, K. Sakashita, T. Sekiguchi, T. Tsukamoto, N. Bhuiyan, G. T. Burton, F. Di Lodovico, J. Gao, T. Katori, R. Kralik, N. Latham, R. M. Ramsden, V. Siccardi, H. Ito, T. Sone, A. T. Suzuki, Y. Takeuchi, S. Wada, H. Zhong, J. Feng, L. Feng, S. Han, J. Hikida, J. R. Hu, Z. Hu, M. Kawaue, T. Kikawa, T. V. Ngoc, T. Nakaya, R. A. Wendell, S. J. Jenkins, N. McCauley, A. Tarrant, M. Fan, M. J. Wilking, Z. Xie, Y. Fukuda, H. Menjo, Y. Yoshioka, J. Lagoda, M. Mandal, Y. S. Prabhu, J. Zalipska, M. Mori, J. Jiang, K. Hamaguchi, H. Ishino, Y. Koshio, F. Nakanishi, T. Tada, T. Ishizuka, G. Barr, D. Barrow, L. Cook, S. Samani, D. Wark, A. Holin, F. Nova, S. Jung, J. Yoo, J. E. P. Fannon, L. Kneale, M. Malek, J. M. McElwee, T. Peacock, P. Stowell, M. D. Thiesse, L. F. Thompson, H. Okazawa, S. M. Lakshmi, E. Kwon, M. W. Lee, J. W. Seo, I. Yu, Y. Ashida, A. K. Ichikawa, K. D. Nakamura, S. Abe, S. Goto, S. Kodama, Y. Kong, H. Hayasaki, Y. Masaki, Y. Mizuno, T. Muro, K. Nakagiri, Y. Nakajima, N. Taniuchi, M. Yokoyama, P. de Perio, S. Fujita, C. Jesus-Valls, K. Martens, Ll. Marti, A. D. Santos, K. M. Tsui, M. R. Vagins, J. Xia, S. Izumiyama, M. Kuze, R. Matsumoto, R. Asaka, M. Ishitsuka, M. Sugo, M. Wako, K. Yamauchi, Y. Nakano, F. Cormier, R. Gaur, M. Hartz, A. Konaka, X. Li, B. R. Smithers, S. Chen, Y. Wu, B. D. Xu, A. Q. Zhang, B. Zhang, H. Adhikary, M. Girgus, P. Govindaraj, M. Posiadala-Zezula, S. B. Boyd, R. Edwards, D. Hadley, M. Nicholson, M. O'Flaherty, B. Richards, A. Ali, B. Jamieson, C. Bronner, D. Horiguchi, A. Minamino, Y. Sasaki, R. Shibayama, R. Shimamura

AI总结 该研究利用超日核四号的数据,通过机器学习方法降低背景噪声,成功观测到低于3.49 MeV的太阳中微子相互作用,并发现其对中微子振荡参数的拟合有显著影响。

Journal ref Phys. Rev. D 113, 112001 (2026)

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AI中文摘要

超日核四号(SK)已观测到$^{8} ext{B}$太阳中微子弹性散射,其反冲电子动能($E_{ ext{kin}}$)低至3.49 MeV,用于研究太阳内部的中微子味转换。在SK可探测能量范围内,这些转换主要由米凯耶夫-斯米尔诺夫-沃尔夫斯坦(MSW)效应主导。预测在更低的能量下,真空中微子振荡将主导电子中微子生存概率的上升,但放射性背景随能量降低而指数级增加。新的机器学习方法在低于3.49 MeV的能量范围内提供了显著的背景减少,使得统计提取太阳中微子相互作用成为可能。本文利用超日核四号的完整运行期数据,采用宽频智能触发系统和提升决策树进行事件选择,观测到2.99 MeV < $E_{ ext{kin}}$ < 3.49 MeV之间的太阳中微子信号,显著性为2.76σ,数据与未振荡蒙特卡洛比率为0.307±0.112。这些额外的低能数据对太阳中微子能谱拟合的1σ区间影响微小,但使用指数参数化时对最佳拟合有显著影响。

英文摘要

Super-Kamiokande (SK) has observed $^{8}\text{B}$ solar neutrino elastic scattering at recoil electron kinetic energies ($E_{\text{kin}}$) as low as 3.49 MeV to study neutrino flavor conversion within the Sun. At SK-observable energies, these conversions are dominated by the Mikheyev-Smirnov-Wolfenstein (MSW) effect. An upturn in the electron neutrino survival probability in which vacuum neutrino oscillations become dominant is predicted to occur at lower energies, but radioactive background increases exponentially with decreasing energy. New machine learning approaches provide substantial background reduction below 3.49 MeV such that statistical extraction of solar neutrino interactions becomes feasible. This article presents an analysis of the solar neutrino interaction rate at $E_{\text{kin}}$ < 3.49 MeV with the full SK-IV period, using data from a wideband intelligent trigger when available and with a boosted decision tree for event selection. A solar neutrino signal is observed between 2.99 MeV < $E_{\text{kin}}$ < 3.49 MeV with $2.76σ$ significance and a data to unoscillated Monte Carlo ratio of $0.307^{+0.112}_{-0.111}$. These additional low-energy data have a negligible effect on the $1σ$ intervals of the fits to the solar neutrino energy spectrum but have a noticeable effect on the best fit when using the exponential parametrization.

2511.09890 2026-06-05 stat.ME stat.AP

A Clustering Approach for Basket Trials Based on Treatment Response Trajectories

基于治疗反应轨迹的篮子试验聚类方法

Masahiro Kojima, Keisuke Hanada, Atsuya Sato

AI总结 本文提出了一种基于治疗反应轨迹转移概率的无模型聚类方法,用于对篮子试验中的篮子进行分组,以提高疗效终点估计的精度和统计功效,同时保持I类错误率在名义水平。

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AI中文摘要

在篮子试验中,有时会观察到疗效的异质性。在本研究中,我们提出了一种无模型的聚类框架,该框架根据治疗反应轨迹导出的转移概率对篮子进行分组,而不是仅依赖单一疗效终点,如客观反应率。簇的数量不是预设的,而是通过数据驱动的方式根据篮子间的相似性结构自动确定。聚类后,同一簇内的篮子使用分层贝叶斯模型进行分析。该框架旨在提高疗效终点的估计精度,增强统计功效,同时保持I类错误率在名义水平。通过模拟研究评估了所提出方法的性能。结果表明,所提出的方法在异质设置中能够准确识别簇结构,并在这样的条件下保持I类错误率在名义水平,同时提高统计功效。

英文摘要

Heterogeneity in efficacy is sometimes observed across baskets in basket trials. In this study, we propose a model-free clustering framework that groups baskets based on transition probabilities derived from the trajectories of treatment response, rather than relying solely on a single efficacy endpoint such as the objective response rate. The number of clusters is not predetermined but is automatically determined in a data-driven manner based on the similarity structure among baskets. After clustering, baskets within the same cluster are analyzed using a hierarchical Bayesian model. This framework aims to improve the estimation precision of efficacy endpoints and enhance statistical power while maintaining the type~I error rate at the nominal level. The performance of the proposed method was evaluated through simulation studies. The results demonstrated that the proposed method can accurately identify cluster structures in heterogeneous settings and, even under such conditions, maintain the type~I error rate at the nominal level while improving statistical power.

2512.23661 2026-06-05 q-bio.NC

Dynamical incompatibilities in paced finger tapping experiments

节律性任务中节律不相容性

Ariel D. Silva, Claudia R. González, Rodrigo Laje

AI总结 本文研究了节律性任务中不同扰动类型对响应时间的影响,发现不同扰动类型在不同实验中存在动态不相容性,但在同一实验中通过随机呈现可实现兼容,挑战了传统相位和周期修正过程的独立激活观念。

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AI中文摘要

节律性任务被用来探测传感器运动同步背后的误差修正机制。尽管已有百年历史,文献中仍存在基本矛盾。其中一种矛盾出现在比较两种最常见的周期扰动类型:阶跃变化和相位移时。刺激序列在包括意外扰动刺激的范围内完全相同。那么为何不同扰动类型会导致下一个响应时间不同,如观察到的?我们通过实验和理论证明,当在不同实验中记录时,两种扰动类型的响应在动态上是不相容的;即它们不能由单一的动态系统描述,因为不同时间背景的积累。相反,当两种扰动类型在同一实验中随机呈现时,响应变得兼容,并可以由单一机制解释。我们得出结论,单一动态系统可以代表所有扰动类型的响应,但仍然通过时间背景进行校准。我们的结果挑战了传统认为不同扰动类型分别激活相位和周期修正过程的观点。

英文摘要

Paced finger-tapping tasks are used to probe the error correction mechanism underlying sensorimotor synchronization. Despite their century-long history, fundamental contradictions persist in the literature. One such contradiction arises when comparing the two most common types of period perturbation: step change and phase shift. The stimulus sequence is exactly the same up to and including the (unexpected) perturbed stimulus. Why then would the timing of the next response be different between perturbation types, as observed? We show, both experimentally and theoretically, that responses to both types of perturbation are dynamically incompatible when recorded in separate experiments; that is, they cannot be described by a single underlying dynamical system due to the build-up of different temporal contexts. In contrast, when both types of perturbation are presented randomly within the same experiment, the responses become compatible and can be explained by a single mechanism. We conclude that a single underlying dynamical system can represent the response to all perturbation types, signs, and sizes, which is nevertheless calibrated by temporal context. Our results challenge the established idea of phase and period correction processes that are separately activated for different perturbation types.

2510.00688 2026-06-05 gr-qc

Non-singular Bouncing Cosmology in $f(R,G,T)$--Quintom model

非奇异 bouncing 宇宙学在 $f(R,G,T)$-quintom 模型中

Farzad Milani

AI总结 本文提出了一种非奇异 bouncing 宇宙学的统一框架,结合 $f(R,G,T)$ 几何与 quintom 标量动力学,在平坦 FLRW 宇宙中实现双 PDL 越过。通过哈密顿分析验证了稳定性,展示了 FLRW 对称性约束如何通过减少高阶导数项至度规不变量来抑制 Ostrogradsky 不稳定性。

Comments 77 pages, 42 figures, 8 appendices, 68 references, 1 table

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AI中文摘要

我们提出了一种非奇异 bouncing 宇宙学的统一框架,在修正引力中结合 $f(R,G,T)$ 几何与 quintom 标量动力学,在平坦 FLRW 宇宙中实现。虽然单场模型可以实现 phantom 分界线 (PDL) 越过和稳定的 bounce,但我们的 $f(R,G,T)$-quintom 耦合提供了一种新的实现方式,使有效参数 $ω_{ ext{eff}}$ 在 bounce 期间实现双 PDL 越过。我们通过哈密顿分析解决了稳定性问题,证明 FLRW 对称性约束通过将高阶导数项减少为度规不变量来抑制 Ostrogradsky 不稳定性。标量场运动方程被显式推导,确认了病态模式的抵消。五种 $f(R,G,T)$ 模型的数值重构证实了非奇异 bounce,具有 $ρ_{ ext{eff}}>0$ 和 $c_s^2 \geq 0$,同时能够对能量条件违反进行参数控制。我们的工作通过以下方式扩展了先前的研究:(1) 将早期时间 bounce 动力学与晚期时间暗能量统一;(2) 展示了与 FLRW 稳定性兼容的新型双 PDL 越过特征;(3) 建立了更高阶导数项的明确无鬼条件。

英文摘要

We present a unified framework for non-singular bouncing cosmologies in modified gravity, combining $f(R,G,T)$ geometry with quintom scalar dynamics in a flat FLRW universe. While single-field models achieve phantom divide line (PDL) crossing and stable bounces, our $f(R,G,T)$-quintom coupling provides a novel implementation of a \textit{double} PDL crossing of $ω_{\text{eff}}$ during the bounce. We address stability concerns through Hamiltonian analysis, showing that FLRW symmetry constraints suppress Ostrogradsky instabilities by reducing higher-derivative terms to metric invariant. The scalar field equation of motion is explicitly derived, confirming cancellation of pathological modes. Numerical reconstruction of five $f(R,G,T)$ models confirms non-singular bounces with $ρ_{\text{eff}}>0$ and $c_s^2 \geq 0$, alongside parametric control over energy condition violations. Our work extends prior studies by: (1) unifying early-time bounce dynamics with late-time dark energy, (2) demonstrating a novel double-PDL crossing signature compatible with FLRW stability, and (3) establishing explicit ghost-free criteria for higher-derivative terms.

2509.02921 2026-06-05 cond-mat.mtrl-sci physics.optics

Tunable Coatings on Various Substrates for Self-Adaptive Energy Harvesting with Daytime Solar Heating and Nighttime Radiative Cooling

可调涂层用于自适应能量收集:日间太阳能加热与夜间辐射冷却

Ken Araki, Vishwa Krishna Rajan, Liping Wang

AI总结 本研究开发了可调钒氧化物(VO2)超材料膜,用于自适应日间太阳能加热和夜间辐射冷却,通过低氧炉氧化在不同基材上制备,实现了高效太阳能吸收和有效夜间散热。

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AI中文摘要

在本工作中,通过低氧炉氧化在不同基材上制备了可调钒氧化物(VO2)超材料膜,用于自适应日间太阳能加热和夜间辐射冷却。由于其热驱动的绝缘体到金属相变行为,VO2超材料膜在白天作为具有高太阳能吸收率(0.86)和低红外发射率(~0.2)的光谱选择性太阳能吸收体,而在夜间则作为选择性冷却器,通过大气透明窗口高效散发热量,具有高发射率(~0.76)向冷外层空间散热。从户外真空测试中观察到,这些可调VO2超材料膜在太阳能加热时温度升高达169 K,夜间温度下降17 K。通过现场拟合大气温度,准确的热传递模型与滞止温度测量结果吻合良好,表明在白天80°C样品温度时加热功率为~400 W/m2,在夜间与环境平衡时30°C时冷却功率为~60 W/m2。本工作将促进开发具有低成本和可扩展制造方法的自适应涂层,用于全天候能量收集。

英文摘要

In this work, tunable vanadium dioxide (VO2) metafilms on different substrate materials fabricated via low-oxygen furnace oxidation are demonstrated for self-adaptive daytime solar heating and nighttime radiative cooling. Because of its thermally-driven insulator-to-metal phase transition behavior, the VO2 metafilms work as spectrally-selective solar absorber with a high solar absorptance of 0.86 and a low infrared emissivity of ~0.2 at daytime, while they behave as selective cooler at nighttime to dissipate heat effectively through the atmospheric transparency window with a high emissivity of ~0.76 to cold outer space. From the outdoor vacuum tests, a significant temperature rise up to 169 K upon solar heating and a temperature drop of 17 K at night are experimentally observed from these tunable VO2 metafilms. With the atmosphere temperature fitted in-situ, the accurate heat transfer model shows excellent agreement with the stagnation temperature measurement, and indicates a high heating power of ~400 W/m2 at 80°C sample temperature in the middle of the day, and a cooling power of ~60 W/m2 at 30°C in equilibrium with ambient at night. This work would facilitate the development of self-adaptive coatings with cost-effective and scalable fabrication approaches for all-day energy harvesting.

2512.19987 2026-06-05 math-ph math.MP physics.class-ph

Harnessing Eversion Buckling for Ideal Omnidirectional Energy Absorption

利用翻转屈曲实现理想的全方位能量吸收

Junjie Liu, Aijie Tang, Mingchao Liu, Xiaoding Wei, Qingsheng Yang

AI总结 本文研究了翻转屈曲机制,通过分析膜能与弯曲能的比值,揭示了轴对称构型在不同几何条件下稳定性转变的机制,并通过有限元模拟和实验验证了该机制在设计具有鲁棒性和方向不敏感性的壳体系统中的应用。

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AI中文摘要

薄壳体的形状变化受弯曲能与膜能之间的竞争所支配。本文识别了翻转的环形壳体中的一种不稳定性机制,称为翻转屈曲。在翻转后,轴对称构型可能保持稳定或通过对称性破坏失去稳定性,这取决于几何形状。通过缩放分析,发现了一个无量纲参数,该参数表征膜能与弯曲能的比值。该参数定义了一个临界阈值,将双稳态区域(轴对称翻转状态持续)与单稳态区域(壳体坍缩成非轴对称构型)分隔开。该转变与pitchfork型分岔一致,导致坍缩而不具有首选平面方向。有限元模拟和实验验证了所提出的缩放关系和相关稳定性边界在不同壳体几何形状下的适用性。在双稳态区域中,单个翻转壳体表现出快速的 snap-through,伴随大的体积收缩,并且临界响应对边界约束具有有限的敏感性。基于该机制,由此类壳体组成的系统形成具有稳定应力平台和高能量吸收效率的颗粒系统。这些结果为设计具有鲁棒性和方向不敏感性的壳体系统提供了基于力学的框架。

英文摘要

Thin shells can undergo large shape changes governed by the competition between bending and membrane energies. Here, we identify an instability mechanism in everted toroidal shells, referred to as eversion buckling. After eversion, the axisymmetric configuration may either remain stable or lose stability through symmetry breaking, depending on geometry. A scaling analysis reveals a dimensionless parameter that characterizes the ratio between membrane and bending energies. This parameter defines a critical threshold separating a bistable regime, where the axisymmetric everted state persists, from a monostable regime, where the shell collapses into a non-axisymmetric configuration. The transition is consistent with a pitchfork-type bifurcation, leading to collapse without a preferred in-plane direction. Finite element simulations and experiments validate the proposed scaling and the associated stability boundary across different shell geometries. In the bistable regime, individual everted shells exhibit rapid snap-through accompanied by large volumetric contraction and show limited sensitivity of the critical response to boundary constraints. Building on this mechanism, assemblies of such shells form granular systems with a stable stress plateau and high energy absorption efficiency. These results provide a mechanics-based framework for designing shell-based systems with robust and direction-insensitive energy absorption.

2512.19745 2026-06-05 quant-ph cond-mat.other physics.class-ph

Observation of flat-band skin effect

观测平坦带皮肤效应

Xulong Wang, Dongyi Wang, Congwei Lu, Ruo-Yang Zhang, Ching Hua Lee, Kun Ding, Guancong Ma

AI总结 研究揭示了非厄米特系统中平坦带皮肤效应的出现机制,发现其与周围分散带的谱拓扑有关,并通过实验验证了非厄米特机械晶格中的这一现象。

Comments This paper supercedes arXiv:2412.19034, which contains erraneous analyses and was posted prematurely. We apologize for any confusion and inconvenience

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AI中文摘要

在一维(1D)厄米特晶格中,对称保护的理想平坦带被紧凑局域态(CLS)填充,这是一种特殊的局域化形式,其波函数被限制在小区域内。在本工作中,我们发现非厄米特皮肤效应(NHSE)可以在平坦带中出现。与传统非厄米特皮肤效应不同,传统非厄米特皮肤效应保护于非平凡点隙拓扑,而平坦带在复能平面上始终是一个点,因此总是拓扑平凡。我们发现,有趣的是,平坦带皮肤效应(FBSE)与包围平坦带的分散带在复能平面上的非平凡谱拓扑有关,因此它只在非厄米特参数的有限范围内出现,并且在非厄米特性增强时可能反直觉地消失。此外,在周期性和开放边界条件下,平坦带与分散带之间的间隙可以在更高阶的例外点处闭合。平坦带波函数在量子距离上跨过这些例外点是不连续的,这表明间隙闭合是奇异的。FBSE在非厄米特机械晶格中被实验观测到。本工作揭示了非厄米特系统中独特的平坦带现象,并突显了量子几何和局域化控制的新可能性。

英文摘要

Symmetry-protected ideal flat bands in one-dimensional (1D) Hermitian lattices are populated by compact localized states (CLS) - a special class of localization with wavefunctions confined within a small region. In this work, we discover that the non-Hermitian skin effect (NHSE) can appear in a flat band. Unlike conventional NHSEs for dispersive bands that are protected by nontrivial point-gap topology, the flat band remains a point on the complex-energy plane and is therefore always topologically trivial. We found that, intriguingly, the flat-band skin effect (FBSE) is associated with the non-trivial spectral topology of the dispersive bands enclosing the flat band on the complex-energy plane, so it only emerges within a finite range of non-Hermitian parameters and can counterintuitively disappear at large non-Hermiticity. Moreover, the gaps between the flat and the dispersive bands can close at higher-order exceptional points under both periodic and open boundary conditions. The flat-band wavefunctions are discontinuous in quantum distance across these exceptional points, signifying that the gap-closing is singular. The FBSE was experimentally observed in a non-Hermitian mechanical lattice. Our work reveals flat-band phenomena unique to non-Hermitian systems and highlights new possibilities in quantum geometry and localization control.

2512.19502 2026-06-05 physics.acc-ph

A Collimation System Baseline Design for the Electron Storage Ring at the Electron-Ion Collider

电子离子对撞机电子存储环的束流校正系统基础设计

Andrii Natochii, Elke-Caroline Aschenauer, Karim Hamdi, Charles Hetzel, Eric Link, Daniel Marx, Christoph Montag, Steven Tepikian, Yunhai Cai, Yuri Nosochkov

AI总结 本文提出了一种电子离子对撞机电子存储环的束流校正系统基础设计,旨在减少高流强电子存储环中由于超导最终聚焦磁铁和敏感探测器引起的束流损失,通过降低束流-气体和Touschek散射引起的相互作用区域束流损失几个数量级,同时保持探测器背景和低温机柜热负荷在可接受范围内。

Comments 12 pages, 9 figures, and 3 tables. Accepted for publication in Physical Review Accelerators and Beams. Selected as an Editors' Suggestion

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AI中文摘要

我们提出了电子离子对撞机(EIC)在布鲁赫斯国家实验室(BNL)电子存储环的束流校正系统基础设计。该系统针对高流强电子存储环中由于超导(SC)最终聚焦磁铁和敏感探测器引起的束流损失问题,其中不受控的损失会产生热量负荷、辐射和探测器背景并造成损坏。所提出的束流校正插入件通过将环形粒子跟踪模拟显示,校正器不会显著影响机器接受度或束流寿命,其位置和孔径可以为未来晶格配置重新优化。正在进行的工作包括将蟹形腔和螺线管磁场纳入模拟,改进真空条件,并优化校正器几何形状和材料。该设计为EIC电子存储环的束流校正系统建立了稳健的基础,并支持继续进行晶格优化以进行机器操作。

英文摘要

We present the baseline design of the electron ring collimation system for the Electron-Ion Collider (EIC) at Brookhaven National Laboratory (BNL). The system addresses beam losses in a high-current electron storage ring with superconducting (SC) final-focus magnets and sensitive detectors, where uncontrolled losses can generate heat loads, radiation, and detector backgrounds and damage. The proposed collimation insertion localizes halo particle losses through reducing interaction region beam losses from beam-gas and Touschek scattering by several orders of magnitude while keeping detector backgrounds and cryostat heat loads within acceptable limits. Multi-turn particle tracking simulations show that the collimators do not significantly impact machine acceptance or beam lifetime, and their positions and apertures can be re-optimized for future lattice configurations. Ongoing work includes incorporating crab cavities and solenoid fields into simulations, refining vacuum conditions, and optimizing collimator geometry and materials. This design establishes a robust baseline for the EIC electron ring collimation system and supports continued lattice optimization for machine operations.

2512.19060 2026-06-05 cs.CC cs.FL

On the complexity of computing Strahler numbers

关于计算Strahler数的复杂性

Moses Ganardi, Markus Lohrey

AI总结 该研究探讨了计算二叉树Strahler数的复杂性,证明了在术语表示下该问题在电路复杂性类uniform NC^1中是完全的,并分析了不同表示形式下的计算复杂性,还证明了判断上下文无关文法是否产生Strahler数至少为k的推导树的问题在P-完全,当推导树为无环时则在PSPACE-完全。

Comments Extended abstract appeared at STACS 2026

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AI中文摘要

它被证明,给定一个二叉树作为术语,计算其Strahler数的问题在电路复杂性类uniform NC^1中是完全的。对于几种变体,其中二叉树以指针结构或通过有向无环图或树直线程序以简洁形式给出,确定Strahler数的复杂性也被确定。我们证明了判断给定的Chomsky正常形式的上下文无关文法是否产生一个Strahler数至少为k的推导树的问题是P-完全的。如果推导树被限制为无环,则该问题变为PSPACE-完全。

英文摘要

It is shown that the problem of computing the Strahler number of a binary tree given as a term is complete for the circuit complexity class uniform $\mathsf{NC}^1$. For several variants, where the binary tree is given by a pointer structure or in a succinct form by a directed acyclic graph or a tree straight-line program, the complexity of computing the Strahler number is determined as well. We show that the problem of deciding whether a given context-free grammar in Chomsky normal form produces a derivation tree with a Strahler number of at least $k$ is $\mathsf{P}$-complete. If the derivation tree is restricted to be acyclic, the problem becomes $\mathsf{PSPACE}$-complete.

2512.18757 2026-06-05 cond-mat.mtrl-sci

Topological surface phonons modulate thermal transport in semiconductor thin films

拓扑表面声子调控半导体薄膜中的热输运

Zhe Su, Shuoran Song, Qi Wang, Jian-Hua Jiang

AI总结 本研究通过结合第一性原理机器学习势能与声子玻尔兹曼输运方程和分子动力学模拟,系统研究了拓扑表面声子在半导体薄膜(Si、4H-SiC和c-BN)平面热输运中的作用,发现其对热导率的贡献可达30%以上,并展示了温度和双轴应变可有效调控该贡献。

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AI中文摘要

尽管晶体固体中的声子拓扑性已广泛研究,但其对热输运,尤其是纳米结构中的影响仍不明确。本文通过结合基于第一性原理的机器学习势能与声子玻尔兹曼输运方程和分子动力学模拟,系统研究了拓扑表面声子在半导体薄膜(Si、4H-SiC和c-BN)平面热输运中的作用。这些拓扑表面声子源自非平凡的声子节点线,不仅作为主导声子的主要散射通道,还对整体热导率有显著贡献。值得注意的是,对于厚度低于10nm的这些半导体薄膜,在300K时该贡献可达到平面热导率的30%以上,最大绝对贡献可达82 W/m-K,突显了其在半导体纳米尺度热输运中的重要作用。此外,我们证明温度和双轴应变均可有效调控该贡献。本工作建立了拓扑表面声子与纳米尺度热输运之间的直接联系,提供了对其作用的首次定量评估,并为拓扑引导的半导体热管理开辟了道路。

英文摘要

While phonon topology in crystalline solids has been extensively studied, its influence on thermal transport-especially in nanostructures-remains elusive. Here, by combining first-principles-based machine learning potentials with the phonon Boltzmann transport equation and molecular dynamics simulations, we systematically investigate the role of topological surface phonons in the in-plane thermal transport of semiconductor thin films (Si, 4H -SiC, and c-BN). These topological surface phonons, originating from nontrivial acoustic phonon nodal lines, not only serve as key scattering channels for dominant acoustic phonons but also contribute substantially to the overall thermal conductivity. Remarkably, for these thin semiconductor films below 10 nm this contribution can be as large as over 30% of the in-plane thermal conductivity at 300 K, and the largest absolute contribution can reach 82 W/m-K, highlighting their significant role in nanoscale thermal transport in semiconductors. Furthermore, we demonstrate that both temperature and biaxial strain provide effective means to modulate this contribution. Our work establishes a direct link between topological surface phonons and nanoscale thermal transport, offering the first quantitative assessment of their role and paving the way for topology-enabled thermal management in semiconductors.

2502.01110 2026-06-05 cs.CR

The Nonlinear Filter Model of Stream Cipher Redivivus

流密码非线性滤波模型再探

Claude Carlet, Palash Sarkar

AI总结 本文针对非线性滤波模型在流密码设计中的安全性与实现效率问题,提出新的布尔函数构造方法,设计出在不同安全级别下具有高效实现的流密码方案。

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AI中文摘要

非线性滤波模型是设计安全流密码的一种古老且广为人知的方法。几十年来的研究已经展示了如何攻击基于该模型的流密码,并确定了用于抵御此类攻击的布尔函数所需的安全属性。这导致了构造既提供充分安全性和又易于实现的布尔函数的问题。不幸的是,在过去二十年中,文献中没有出现完全令人满意的解决方案。缺乏良好的解决方案使得非线性滤波模型在某种程度上变得过时。这对密码学设计工具包来说是一个重大损失,因为该模型的优势在于其简单性、良好的安全性和为面向硬件的流密码提供低成本解决方案的潜力。在本文中,我们通过构造适当的布尔函数来复兴非线性滤波模型,这些布尔函数提供了所需的安全性并易于实现。我们提出了具体的流密码建议,这些流密码对已知类型的攻击具有κ位的安全性,对于κ=80、128、160、192、224和256。对于80位和128位安全级别,我们的提案的门级估计与著名的Trivium和Grain-128a密码相比相当良好,而对于256位安全级别,我们不知道有其他流密码设计具有如此低的门级数。

英文摘要

The nonlinear filter model is an old and well understood approach to the design of secure stream ciphers. Extensive research over several decades has shown how to attack stream ciphers based on this model and has identified the required security properties of the Boolean function used as the filtering function to resist such attacks. This led to the problem of constructing Boolean functions which provide adequate security \textit{and} at the same time are efficient to implement. Unfortunately, over the last two decades no fully satisfactory solutions to this problem appeared in the literature. The lack of good solutions has effectively led to the nonlinear filter model becoming more or less obsolete. This is a big loss to the cryptographic design toolkit, since the great advantages of the nonlinear filter model are its simplicity, well understood security and the potential to provide low cost solutions for hardware oriented stream ciphers. In this paper, we revive the nonlinear filter model by constructing appropriate Boolean functions which provide required security and are also efficient to implement. We put forward concrete suggestions of stream ciphers which are $κ$-bit secure against known types of attacks for $κ=80$, 128, 160, 192, 224 and 256. For the 80-bit and the 128-bit security levels, the gate count estimates of our proposals compare quite well to the famous ciphers Trivium and Grain-128a respectively, while for the 256-bit security level, we do not know of any other stream cipher design which has such a low gate count.

2402.02247 2026-06-05 math.NA cs.NA

Novel approaches for the reliable and efficient numerical evaluation of Landau-type operators

Landau型算子可靠高效数值评估的新方法

Jose Antonio Carrillo, Mechthild Thalhammer

AI总结 针对Landau型碰撞算子中的奇异积分核,提出基于配置法、傅里叶谱方法及预计算的新数值方法,实现可靠高效评估。

Comments 34 pages

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AI中文摘要

Landau型算子的数值近似是处理非均匀Vlasov-Landau型方程等复杂问题的时间积分方法的基本组成部分。处理物理上最相关的三维库仑相互作用情况会带来大量计算问题。本文关注于引入并数值比较用于可靠高效评估Landau型碰撞算子的新方法,重点处理涉及一般奇异积分核的积分算子。在配置法思想下,常用工具包括基本积分的识别、积分核和密度函数在速度域主要部分的级数展开,以及在核奇点附近的插值和求积近似。聚焦于傅里叶谱方法的有利选择,其实践实现利用基本积分的简化、快速傅里叶技术以及沿特定方向的求和。此外,一个重要观察是整体计算工作量中有显著比例可以转移到独立于密度函数的预计算中。为了说明和数值验证,区分了常数、正则和奇异积分核的情况,并根据问题复杂度的增加相应调整过程。

英文摘要

Numerical approximations of Landau-type operators represent fundamental components of time integration methods for demanding problems such as inhomogeneous Vlasov-Landau-type equations. Substantial computational issues arise from the treatment of the physically most relevant three-dimensional case with Coulomb-type interaction. This work is concerned with the introduction and numerical comparison of novel approaches for the reliable and efficient evaluation of Landau-type collision operators, where the focus is on the treatment of integral operators involving general singular kernels. In the spirit of collocation, common tools are the identification of fundamental integrals, series expansions of the integral kernel and the density function on the main part of the velocity domain, and interpolation as well as quadrature approximation nearby the singularity of the kernel. Focusing on the favourable choice of the Fourier spectral method, their practical implementation uses the reduction to basic integrals, fast Fourier techniques, and summations along certain directions. Moreover, an important observation is that a significant percentage of the overall computational effort can be transferred to precomputations which are independent of the density function. For the purpose of exposition and numerical validation, the cases of constant, regular, and singular integral kernels are distinguished, and the procedure is adapted accordingly to the increasing complexity of the problem.

2512.17763 2026-06-05 math.AP math.SP

Trapped modes in electromagnetic waveguides

电磁波导中的受困模式

Anne-Sophie Bonnet-Ben Dhia, Lucas Chesnel, Sonia Fliss

AI总结 研究电磁波导中受困模式的存在性,通过分析Maxwell方程组在不同几何结构下的解,探讨受困模式与Maxwell算子本征值的关系及非均匀波导中的特殊机制。

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AI中文摘要

我们考虑在三维无界领域中,由一个有限共振腔和一个或多个半无限波导组成的Maxwell方程组,具有完美电导边界条件。我们关注电磁受困模式的存在性,即无源项下的L²解。这些受困模式与Maxwell算子的本征值有关,这些本征值可以位于本征谱之下或嵌入其中。首先,对于均匀波导,我们提出不同的几何结构,证明本征值的存在。然后,我们展示某些非均匀波导,其介电常数存在局部扰动,支持受困模式。值得注意的是,我们提出的一些机制非常特定于Maxwell方程,而没有等价于标量Dirichlet或Neumann拉普拉斯算子的对应机制。

英文摘要

We consider the Maxwell's equations with perfect electric conductor boundary conditions in three-dimensional unbounded domains which are the union of a bounded resonator and one or several semi-infinite waveguides. We are interested in the existence of electromagnetic trapped modes, i.e. $L^2$ solutions of the problem without source term. These trapped modes are associated to eigenvalues of the Maxwell's operator, that can be either below the essential spectrum or embedded in it. First for homogeneous waveguides, we present different families of geometries for which we can prove the existence of eigenvalues. Then we exhibit certain non homogeneous waveguides with local perturbations of the dielectric constants that support trapped modes. Let us mention that some of the mechanisms we propose are very specific to Maxwell's equations and have no equivalent for the scalar Dirichlet or Neumann Laplacians.

2512.17509 2026-06-05 astro-ph.CO astro-ph.IM

CLiENT: A new tool for emulating cosmological likelihoods using deep neural networks

CLiENT:利用深度神经网络模拟宇宙学似然函数的新工具

Luca Janken, Steen Hannestad, Thomas Tram, Andreas Nygaard

AI总结 本文提出CLiENT,一种利用深度神经网络直接模拟数据集似然函数的方法,相比传统观测模拟方法,具有自动生成可微分代理似然函数的优势,能够在较少函数评估次数下获得高精度的置信区间和参数空间内的χ²精度。

Comments 23 pages, 10 figures. Accepted for publication in JCAP. Code available at https://github.com/AarhusCosmology/client_public

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AI中文摘要

近年来,由于在宇宙学参数推断或模型比较中节省计算时间的潜力,对可观测量(如宇宙微波背景谱和物质功率谱)的宇宙学模拟变得越来越普遍。本文介绍了CLiENT(使用TensorFlow的神经网络宇宙学似然模拟器),一种新的方法,通过直接模拟数据集的似然函数来替代计算可观测量。我们发现该方法在所需函数评估次数方面与观测模拟器具有竞争力,但具有独特的优势,即生成完全可微分的代理似然函数。使用少于2×10⁴次函数评估,CLiENT通常能够获得比使用真实似然和单点模拟器获得的置信区间更精确的区间,误差小于0.1σ,且在相关参数空间区域内的单点模拟精度优于Δχ²≈0.5。

英文摘要

Cosmological emulation of observables such as the Cosmic Microwave Background (CMB) spectra and matter power spectra have become increasingly common in recent years because of the potential for saving computation time in connection with cosmological parameter inference or model comparison. In this paper we present CLiENT (Cosmological Likelihood Emulator using Neural networks with TensorFlow), a new method which circumvents the computation of observables in favour of directly emulating the likelihood function for a data set given a model parameter vector. We find that the method is competitive with observable emulators in terms of the required number of function evaluations, but has the distinct advantage of producing a surrogate likelihood which is completely auto-differentiable. Using less than $2 \times 10^4$ function evaluations CLiENT typically achieves credible intervals within better than $0.1 σ$ of those obtained using the true likelihood and single-point emulator precision better than $Δχ^2 \sim 0.5$ across relevant regions in parameter space.

2510.26137 2026-06-05 math-ph math.CO math.MP

GUE Correlators and Large Genus Asymptotics

GUE相关函数与高阶渐近行为

Jiayi Zhao

AI总结 本文利用Dubrovin和Yang(2017)推导的公式,研究GUE相关函数的渐进行为,特别是普通图和带状图的高阶渐近行为。

Journal ref SIGMA 22 (2026), 056, 10 pages

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AI中文摘要

在本文中,我们使用Dubrovin和Yang(2017)推导的公式来研究GUE(Gaussian unitary ensemble)相关函数的某些渐进行为。更具体地说,我们获得了普通图和具有1个面的带状图的高阶渐近行为。

英文摘要

In this paper, we use a formula obtained by Dubrovin and Yang (2017) to study certain asymptotic behaviors of GUE (Gaussian unitary ensemble) correlators. More precisely, we obtain large genus asymptotics of enumerations of ordinary graphs and ribbon graphs with 1 face.