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2605.23680 2026-05-25 astro-ph.EP

Modeling (Sub-)millimeter Scattering Properties of Fractal and Consolidated Porous Particles: Applications to Protoplanetary Disks

分形和多孔凝聚颗粒的(亚)毫米散射特性建模:对原行星盘的应用

Gonzalo Vargas, Daniel Guirado, Carlos Carrasco-Gonzalez, Olga Munoz, Maxim A. Yurkin, Enrique Macias, Jesus M. Jaquez-Dominguez, Francisco J. Garcia-Izquierdo

AI总结 本文研究了 fractal 和压实多孔颗粒在亚毫米波段的散射特性,应用于原行星盘模型。通过离散偶极近似(ADDA)和多球 T 矩方法(MSTM)分别计算了压实多孔颗粒和高度多孔聚集体的散射矩阵、截面及有效反照率。研究发现,孔隙率增加会增强前向散射并增强接近 90 度时的偏振特性。结果表明,多孔颗粒在较大尺寸时仍能保持与反照率约束一致的特征,同时孔隙率还能降低固定尘埃质量下的吸收系数,暗示在给定连续谱辐射下,推导出的尘埃质量更大。

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Comments
18 pages, 8 figures, 8 tables. Accepted for publication in The Astrophysical Journal
AI中文摘要

我们对两种尘埃群体进行了光散射数值模拟:(i) 使用离散偶极子近似(ADDA)计算的致密多孔颗粒,以及(ii) 使用多球T矩阵方法(MSTM)计算的高度多孔聚集体模型,包括分形和层次聚集体。使用DSHARP光学常数,我们计算了尺寸分布n(a) ∝ a^q(q = -3.5,amin = 0.1微米)在0.87至10毫米十个波长下的散射矩阵、截面和有效反照率ω_eff。我们发现,增加孔隙率会增强前向散射,并增强θ约90度附近的极化。对于致密球体,P(90度) × ω_eff在amax ≈ λ/(2π)附近达到峰值然后下降,而多孔颗粒则显示出延伸到更大尺寸的更宽峰值,使基于极化的约束与amax ≈ 1毫米兼容。相对于致密球体,孔隙率还降低了固定尘埃质量下的κ_abs,意味着对于给定的连续谱通量,推断的尘埃质量更大。

英文摘要

We perform light-scattering numerical simulations for two dust populations: (i) consolidated porous particles computed with the discrete dipole approximation (ADDA) and (ii) highly porous aggregate models, including fractal and hierarchical aggregates, computed with the multiple-sphere T-matrix method (MSTM). Using DSHARP optical constants, we compute scattering matrices, cross sections, and effective albedo omega_eff for a size distribution n(a) proportional to a^q, with q = -3.5, amin = 0.1 micron, and ten wavelengths from 0.87 to 10 mm. We find that increasing porosity strengthens forward scattering and enhances polarization near theta approximately 90 degrees. For compact spheres, P(90 degrees) times omega_eff peaks near amax approximately lambda divided by 2 pi and then declines, whereas porous particles show a broader peak extending to larger sizes, keeping polarization-based constraints compatible with amax approximately 1 mm. Porosity also lowers kappa_abs at fixed dust mass relative to compact spheres, implying larger inferred dust masses for a given continuum flux.

2605.21678 2026-05-25 astro-ph.SR

29SiO and 30SiO J=1--0 maser signatures in Galactic AGB stars: the impact of third dredge up and turbulence velocity

29SiO 和 30SiO J=1--0 脉泽在银河系 AGB 星中的特征:第三次挖掘和湍流速度的影响

M. O. Lewis, L. O. Sjouwerman, Y. M. Pihlström, H. J. van Langevelde, R. Bhattacharya, M. C Stroh

AI总结 29SiO和30SiO的J=1--0毫米波跃迁在银河系渐近巨星分支(AGB)星中表现出独特的maser特征,研究发现这一特征与第三混合层上升及低湍流速度有关。通过分析红外颜色选择的BAaDE调查数据,研究人员识别出35个主要由同位素跃迁主导的maser谱线(iso-dom谱)。研究指出,这些谱线增强可能源于第三混合层上升带来的同位素丰度变化以及低湍流速度导致的谱线重叠效应,从而有效泵浦maser跃迁。

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Comments
17 pages, 4 figures, 3 tables, accepted by A&A
AI中文摘要

43 GHz 的 J=1--0 SiO 脉泽在渐近巨星分支(AGB)星中具有明确特征。28SiO 跃迁通常主导这些谱线,其中 v=1 和 v=2 发射尤为突出且普遍存在。关于奇特星中 29SiO 丰度增强的若干预测促使我们编录 29SiO 脉泽发射相对于 28SiO 增强的案例。我们的目的是编录已知的由同位素体跃迁发射主导的 43 GHz 谱(iso-dom 谱)案例,探索这些源的共性,并解释此类脉泽特征的成因。我们的编录来自红外颜色选择的 BAaDE 巡天中的 SiO 脉泽线比,并辅以文献探测。BAaDE 编录巩固了 43 GHz SiO 脉泽的典型特征,显示其由 v=1 和 v=2 线主导。识别出 35 个 iso-dom 谱,意味着该特征出现在约 0.2% 的含 SiO 脉泽星中。与同周期的其他源相比,它们的红外颜色偏蓝,类似于所有显示同位素体脉泽的源。显然,源的 iso-dom 性质是可变的,但尚不清楚这是否与恒星相位有关。iso-dom 源中较大的丰度异常不被支持,因为 iso-dom 源与其他拥有同位素体脉泽的星并无显著差异。脉泽抽运影响特定跃迁的粒子数反转,可以解释增强的特征。我们假设 iso-dom 谱出现在经历过第三次挖掘(轻微增强 29SiO 和 30SiO 丰度)且同时经历极低湍流速度(<1 km/s)的 AGB 星中,从而产生线重叠,非常有效地抽运脉泽跃迁。

英文摘要

J=1--0 SiO masers at 43 GHz have a well-established distinctive signature in asymptotic giant branch (AGB) stars. 28SiO transitions typically dominate these spectra with the v=1 and v=2 emission being especially prominent and ubiquitous. Several predictions about enhanced 29SiO abundances in exotic stars prompt us to catalog the cases where 29SiO maser emission is enhanced compared to 28SiO. Our purpose is to catalog the known cases of 43 GHz spectra dominated by emission from isotopologue transitions (iso-dom spectra), to explore the commonalities in these sources, and to explain the cause of such maser signatures. Our catalog is drawn from SiO maser line ratios in the infrared-color-selected BAaDE survey and supplemented with a literature detection. The BAaDE catalog has cemented the typical signature of 43 GHz SiO masers, showing it is dominated by the v=1 and v=2 lines. Thirty-five iso-dom spectra are identified, meaning that this signature is seen in about 0.2% of our SiO maser-bearing stars. Their infrared colors are blue compared to other sources of the same period, similar to all sources displaying isotopologue masers. It is clear that the iso-dom nature of sources is variable, but unclear whether this is tied to stellar phase. A large abundance abnormality among the iso-dom sources is disfavored as the iso-dom sources do not appear significantly different from other stars which host isotopologue masers. Maser pumping, affecting the population inversions of specific transitions, can instead explain the enhanced signatures. We posit that iso-dom spectra appear in AGB stars which have undergone third-dredge up (enhancing the 29SiO and 30SiO abundance slightly) and which, in addition, are experiencing very low turbulence velocity (<1 km/s), creating a line overlap which pumps the maser transitions very efficiently.

2605.16526 2026-05-25 astro-ph.SR astro-ph.HE

SN 2023fyq: direct detection of a Type Ibn supernova progenitor and its multi-wavelength environmental constraints

SN 2023fyq:Ibn型超新星前身星的直接探测及其多波段环境约束

Xinyi Hong, Ning-Chen Sun, Yali Shao, Ke Wang, Junjie Wu, Qiang Xi, Yi-Han Zhao, Justyn Maund, Xiaohan Chen, Anyu Wang, Linxi Zhang, Jifeng Liu

AI总结 SN 2023fyq 是首颗直接探测到前身星的 Type Ibn 型超新星,其前身星被确认为一颗高温高光度的恒星,并可能属于一个恒星团。研究通过多波段数据揭示了前身星的环境特征,支持其为双星系统中的低质量氦星与致密天体相互作用的产物,为 Type Ibn 超新星的形成机制提供了新的证据。

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Comments
12 pages, 11 figures
AI中文摘要

背景。Ibn型超新星(SNe)以来自抛射物-星周介质相互作用的窄氦发射线为特征,但其前身星仍有争议,提出了大质量沃尔夫-拉叶星和双星中的低质量氦星两种可能。目标。我们旨在直接识别Ibn型超新星SN 2023fyq的前身星,并表征其环境,以约束前身星的性质和演化通道。方法。我们基于爆炸前和晚期的HST和JWST图像搜索超新星前身星,并通过拟合光谱能量分布推导其性质。我们利用包括HST和JWST成像、VLT/MUSE积分场单元光谱和ALMA CO (2--1)射电干涉测量的多波段数据集,通过探测恒星、尘埃、电离气体和分子气体来研究超新星环境。结果。我们在超新星位置发现了一个爆炸前源,该源与一个高温($T>$15000 K)且明亮(log($L$/$L_\odot$) $\gtrsim$ 5.5)的超新星前身星以及一个可能的宿主星团一致。该前身星被证实在爆炸后消失。对超新星环境的分析表明,前身星的年龄可能为log($t$/yr) = 7.1--7.2。这些现象不利于非常巨大的单星前身星,而是支持涉及低质量氦星和致密天体的双星场景;观测到的前身星发射可能源于至少在爆炸前$\sim$12年开始的双星相互作用。结论。SN 2023fyq是第一个直接探测到前身星和可能宿主星团的Ibn型超新星。它增加了Ibn型超新星在前身星通道和质量损失机制方面的多样性。

英文摘要

Context. Type Ibn supernovae (SNe) are characterized by narrow helium emission lines arising from ejecta-circumstellar medium interaction, yet their progenitors remain debated, with both massive Wolf-Rayet stars and low-mass helium stars in binaries proposed. Aims. We aim to directly identify the progenitor of the Type Ibn SN 2023fyq and to characterize its environment in order to constrain the progenitor's nature and evolutionary channel. Methods. We search for the SN progenitor based on pre-explosion and late-time HST and JWST images and derive its properties by fitting the spectral energy distribution. We investigate the SN environment by probing the stars, dust, ionized gas and molecular gas with a multi-wavelength dataset including HST and JWST imaging, VLT/MUSE integral-field-unit spectroscopy and ALMA CO (2--1) radio interferometry. Results. We discover a pre-explosion source at the SN position, which is consistent with a hot ($T>$15000 K) and luminous (log($L$/$L_\odot$) $\gtrsim$ 5.5) SN progenitor and a possible host star cluster. The progenitor is confirmed to have disappeared after explosion. Analysis of the SN environment implies that the progenitor likely has an age of log($t$/yr) = 7.1--7.2. These phenomena disfavor a very massive single-star progenitor and instead support a binary scenario involving a low-mass helium star and a compact object; the observed progenitor emission likely arises from binary interaction that began at least $\sim$12 yr before the explosion. Conclusions. SN 2023fyq is the first Type Ibn SN with a directly detected progenitor and a possible host star cluster. It adds to the diversity of Type Ibn SNe in terms of their progenitor channels and mass-loss mechanisms.

2605.23900 2026-05-25 hep-th

What to do with a Ricci-flat Calabi--Yau metric?

如何处理 Ricci-flat Calabi-Yau 度量?

Per Berglund, Tristan Hübsch, Vishnu Jejjala

AI总结 本文探讨了在弦论紧致化中,如何利用数值计算得到的里奇平坦卡拉比-爱因斯坦度量来获取新的物理和数学信息。传统上,紧致化的研究主要依赖于拓扑和全纯数据,而数值度量使得计算物质凯勒度量、约化耦合、卡鲁扎-克莱因谱等非全纯物理量成为可能。此外,该方法还为模稳定、α'修正背景、德西特模型构建等重要问题提供了定量输入,并为研究特殊拉格朗日子流形、镜像对称等数学问题开辟了计算途径。

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Comments
50 pages, for Proceedings of "Recent Progress in Computational String Geometry'' workshop, BIRS/CMI, 2026
AI中文摘要

Ricci-flat Calabi-Yau 度量的数值近似使得超越传统上主导显式弦紧致化的拓扑和全纯数据成为可能。本文解释了一旦度量以及最终的 Hermitian Yang-Mills 丛数据可以计算,哪些新的物理和数学变得可访问。在杂化紧致化中,这些数据对于确定物质 Kähler 度量、规范归一化的 Yukawa 耦合、Kaluza-Klein 谱、阈值效应、软项以及四维有效作用量的其他非全纯成分是必需的。更广泛地说,数值 Calabi-Yau 几何为模稳定化、α'修正背景、de Sitter 模型构建、轴子物理、沼泽地距离测试以及内几何随时空变化的紧致化提供了定量输入。几何数据允许对涉及特殊拉格朗日子流形、SYZ 纤维化、镜像对称、校准几何、度量退化、Ricci-flat 度量到纤维的限制以及解析或半解析结构搜索的长期数学问题进行计算研究。我们将这些方向作为未来工作的路线图。

英文摘要

Numerical approximations to Ricci-flat Calabi--Yau metrics make it possible to move beyond the topological and holomorphic data that have traditionally dominated explicit string compactifications. This article explains what new physics and mathematics become accessible once the metric, and eventually the associated Hermitian Yang--Mills bundle data, can be computed. In heterotic compactifications, such data are needed to determine matter Kähler metrics, canonically normalized Yukawa couplings, Kaluza--Klein spectra, threshold effects, soft terms, and other non-holomorphic ingredients of the four-dimensional effective action. More broadly, numerical Calabi--Yau geometry provides quantitative input for moduli stabilization, $α'$-corrected backgrounds, de~Sitter model building, axion physics, swampland distance tests, and compactifications in which the internal geometry varies over spacetime. Geometric data permit a computational approach to long-standing mathematical questions involving special Lagrangian submanifolds, SYZ fibrations, mirror symmetry, calibrated geometry, metric degeneration, restrictions of Ricci-flat metrics to fibers, and the search for analytic or semi-analytic structures. We present these directions as a roadmap for future work.

2605.23894 2026-05-25 quant-ph cs.IT math.IT

A Two-Branch Finite-Field Construction for Regular CSS LDPC Bases

正则CSS LDPC基矩阵的双分支有限域构造

Koki Okada, Kenta Kasai

AI总结 本文提出了一种用于构建正则CSS量子低密度奇偶校验码基矩阵的双分支有限域构造方法。该方法通过有限域上的商群余类条件,将正则性、CSS正交性和同类型四环排除等要求转化为显式条件,并通过归一化穷举搜索生成多个不同度分布的基矩阵。该构造将有限长度设计分为两个阶段,基矩阵固定度分布和初始环约束,随后通过循环提升随机化边连接,同时满足精确代数条件。实验表明,该方法构造的量子码在纠错性能上表现优异,具有较高的码距和较低的帧错误率。

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AI中文摘要

本文针对正则Calderbank-Shor-Steane (CSS)量子低密度奇偶校验基矩阵,提出了一种双分支乘法陪集构造方法。对于目标列重\(J\)和偶行重\(L\),该方法将正则性、CSS正交性和同类型4环排除归结为有限域上的显式商-陪集条件。对这些条件进行归一化穷举搜索,可生成若干\((J,L)\)对的基矩阵,因此该构造不局限于单一度分布。该构造将有限长设计分为两个阶段:基矩阵固定度分布和第一围长约束,而循环提升则通过精确代数检验随机化边连接。作为详细示例,我们将一个\((3,10)\)-正则基矩阵经历提升和解码阶段。对于该示例,选定的64倍提升得到的码,其同类型Tanner图围长至少为8,并且排除了一个指定的重量16非简并逻辑支撑轨道。最终实例是一个\([[10240,4108,\,10\le d\le32]]\) CSS码。解码方面,我们使用联合对数域置信传播以及针对小残差综合征的低复杂度确定性后处理规则,包括修复具有两个不满足校验的残差模式。帧错误率(FER)测量为该详细示例提供了有限长解码数据;在去极化概率\(p=0.058\)时,后处理FER为\(1.0 imes10^{-7}\)。

英文摘要

This paper develops a two-branch multiplicative-coset construction for regular Calderbank-Shor-Steane (CSS) quantum low-density parity-check base matrices. For a target column weight \(J\) and an even row weight \(L\), the method reduces regularity, CSS orthogonality, and same-type 4-cycle exclusion to explicit quotient-coset conditions over a finite field. A normalized exhaustive search for these conditions produces base matrices for several \((J,L)\) pairs, so the construction is not tied to a single degree distribution. The construction separates the finite-length design into two stages: the base matrix fixes the degree distribution and the first girth constraints, and a cyclic lift randomizes edge connections subject to exact algebraic checks. As a detailed example, we carry one \((3,10)\)-regular base through the lift and decoding stages. For this example, the selected 64-fold lift gives a code whose same-type Tanner graphs have girth at least eight, and it also excludes a specified weight-16 nondegenerate logical-support orbit. The resulting instance is a \([[10240,4108,\,10\le d\le32]]\) CSS code. For decoding, we use joint log-domain belief propagation together with low-complexity deterministic post-processing rules for small residual syndromes, including repairs for residual patterns with two unsatisfied checks. The frame error rate (FER) measurements provide finite-length decoding data for this detailed example; at depolarizing probability \(p=0.058\), the post-processing FER is \(1.0\times10^{-7}\).

2605.23886 2026-05-25 hep-th

Heterotic Strings on Enriques Surfaces

Enriques曲面上的杂化弦

Arata Ishige, Elisa Iris Marieni

AI总结 本文研究了异otic弦理论在Enriques曲面上的轨道折叠紧致化。作者对E8×E8和Spin(32)/Z₂格子的非等价位移向量进行了分类,并分析了所得模型的轻子谱。研究显示这些模型可以解释为十维非超对称异otic弦在Enriques曲面上的紧致化,某些位移类别的模型能够消除来自父理论的模无关快子。

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Comments
32 pages, 7 tables
AI中文摘要

我们研究了杂化弦在Enriques曲面上的轨道紧化。我们分类了E8×E8和Spin(32)/Z2格点的不等价平移向量,并分析了所得模型的光频谱。我们证明这些模型可以解释为十维非超对称杂化弦在Enriques曲面上的紧化。对于某些平移类,继承自母理论的模无关快子被投影掉。

英文摘要

We study orbifold compactifications of heterotic strings on Enriques surfaces. We classify the inequivalent shift vectors for both the E8\times E8 and Spin(32)/Z2 lattices, and analyse the light spectrum of the resulting models. We show that these models can be interpreted as compactifications of ten-dimensional non-supersymmetric heterotic strings on Enriques surfaces. For certain classes of shifts, the moduli-independent tachyons inherited from the parent theories are projected out.

2605.23884 2026-05-25 math.FA math-ph math.CA math.MP math.SP

On almost periodicity in crystalline measures

关于晶体测度的几乎周期性

Jan Mazáč, Christoph Richard, Nicolae Strungaru

AI总结 本文研究晶格测度的几乎周期性问题,探讨其作为分布的性质。作者证明了晶格测度的几乎周期性可由其平移有界性刻画,并构造了反例表明并非所有晶格测度都是平移有界的分布。通过构建特殊的晶格傅里叶特征测度,论文澄清了Meyer和Favorov提出的问题,明确了晶格测度在平移有界性方面的边界,并揭示了其在傅里叶类准晶体之外的特殊行为。

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Comments
34 pages
AI中文摘要

Meyer将晶体测度定义为满足其本身及其傅里叶变换$\widehatμ$都是局部有限支撑的纯点Radon测度的缓增分布$μ$。他猜想每个晶体测度作为缓增分布是几乎周期的。Favorov构造了一个反例,并询问晶体测度是否至少作为一般分布是几乎周期的。为了解决Favorov的问题,我们首先证明,在Radon测度、缓增分布或一般分布的任何类别中,晶体测度的几乎周期性可以用其平移有界性来刻画。然后我们构造了一个晶体傅里叶本征测度,它甚至作为分布也不是平移有界的。最后我们构造了一个晶体测度,它不是傅里叶准晶(特别地,它不是缓增的),但它是几乎周期的缓增分布,其傅里叶变换甚至是范数几乎周期测度。我们的例子完全解决了Meyer和Favorov的问题,并清晰地划定了平移有界性的类边界。它们还展示了晶体测度在傅里叶准晶类之外的异常行为。

英文摘要

Meyer defined crystalline measures as tempered distributions $μ$ such that both $μ$ and its Fourier transform $\widehatμ$ are pure-point Radon measures of locally finite support. He conjectured that every crystalline measure is almost periodic as a tempered distribution. Favorov constructed a counterexample and asked whether crystalline measures are at least almost periodic as general distributions. To resolve Favorov's question, we first show that the almost periodicity of a crystalline measure is characterised in terms of its translation boundedness, in any class of Radon measures, tempered distributions, or general distributions. We then construct a crystalline Fourier eigenmeasure that fails to be translation bounded even as a distribution. We finally construct a crystalline measure that fails to be a~Fourier quasicrystal (in particular, it fails to be slowly increasing), but it is an almost periodic tempered distribution whose Fourier transform is even a norm almost periodic measure. Our examples fully resolve the questions of Meyer and Favorov and sharply delineate the class boundary of translation boundedness. They also demonstrate the unusual behaviour of crystalline measures beyond the class of Fourier quasicrystals.

2605.23882 2026-05-25 physics.optics

Breaking order: Talbot effect with spinodal architectures

打破秩序:旋节线结构中的Talbot效应

Robin Krüger, Jeevan Rois, Martin Bech, Matias Kagias

AI总结 本文研究了在非周期性结构中是否会出现类似传统塔尔博特效应的周期性光场重构现象。通过理论分析与实验验证,作者发现受超材料启发的随机斯宾多尔结构在可见光和硬X射线波段均能表现出显著的塔尔博特效应。该成果为X射线暗场成像提供了新的光学方案,有效结合了传统光栅和扩散器的优缺点,为物质表征与操控开辟了新途径。

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AI中文摘要

Talbot效应描述了扰动传播波场中周期性图案的出现。该效应在结构相干光学(如衍射光栅)的扰动中已被充分研究。自由形态和超光学设计的出现提出了一个问题:是否也能从复杂的非周期结构中观察到类似行为?在这里,我们证明了受近期超材料设计启发的随机结构表现出强烈的类Talbot行为。通过随机旋节线结构在特定传播距离上投影波前的重现,在可见光和硬X射线波段得到了理论和实验验证。该现象的一个直接应用是用于表征人工和天然介观结构材料的X射线暗场成像。我们的工作表明,旋节线X射线光学有效弥合了暗场X射线成像中两种对立方法(即主张空间完全相干的光学(如光栅)和非相干的光学(如扩散器))之间的差距。这为探索X射线成像方法实施的新维度打开了机遇。鉴于经典Talbot效应的影响力和普遍性,我们期望我们的工作能够为表征和操控物质提供新的机会。

英文摘要

The Talbot effect describes the emergence of periodic patterns in perturbed propagating wave fields. The effect is well studied for perturbations from structurally coherent optics such as diffraction gratings. The emergence of freeform and metaoptical designs raises the question of whether comparable behavior can also be observed from complex, non-periodic structures. Here we demonstrate that stochastic structures inspired by recent metamaterial designs, display a strong Talbot-like behavior. Re-emergence of projected wavefronts through stochastic spinodal architectures at distinct propagation distances are proven theoretically and experimentally in the visible and hard X-ray regimes. A direct application of this phenomenon is X-ray dark-field imaging for characterizing artificial and natural meso-structured materials. Our work shows that spinodal X-ray optics effectively bridge the gap between the two opposing approaches in dark-field X-ray imaging that advocate for either spatially fully coherent (i.e gratings) or incoherent (i.e diffusers) optics. This opens opportunities for exploring a new dimension in the implementation of X-ray imaging methods. Given the impact and universality of the classical Talbot effect, we expect our work to enable new opportunities for characterizing and manipulating matter.

2605.23881 2026-05-25 cond-mat.quant-gas quant-ph

Time crystals in cavity-BEC systems

腔-BEC系统中的时间晶体

Jayson G. Cosme, Ludwig Mathey

AI总结 本文研究了在腔-玻色-爱因斯坦凝聚体(BEC)系统中实现的时间晶体态。通过光子发射的实时读取,该系统能够有效模拟动态现象,并克服了传统时间-of-flight成像的破坏性限制。作者回顾了三种不同类型的预测和实现的时间晶体态,并基于简化的多模模型对每种状态进行了示例分析,通过腔模关联函数和凝聚体动量模式特征对其进行了表征,为动态现象的建模和研究提供了清晰的框架和参考。

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Comments
14 pages, 13 figures
AI中文摘要

对光诱导动力学态的理解一直是科学中具有挑战性和富有成果的追求。这一追求得到了动力学现象量子模拟的支持,例如在超冷原子系统中。通常,超冷原子动力学通过飞行时间成像进行破坏性读出,限制了详细分析。然而,原子-腔系统通过腔的光子发射提供光子态的实时读出,使系统非常适合模拟动力学现象。在这里,我们综述了在腔-BEC系统中预测和实现的三种不同时间晶体态。我们基于最小少模模型为每种态给出了示例。我们通过腔模和凝聚体特征动量模的关联函数来表征时间晶体态。这支持了这些时间晶体之间的清晰区分。更一般地,这里综述的研究序列为建立动力学现象的最小模型及其表征提供了蓝图。

英文摘要

The understanding of light-induced dynamical states continues to be a challenging and fruitful pursuit of science. This pursuit is supported by quantum simulation of dynamical phenomena, e.g., in ultracold atom systems. Typically, ultracold atom dynamics are read out destructively, via time-of-flight imaging, limiting a detailed analysis. However, atom-cavity systems provide a real-time readout of the photonic state via photon emission from the cavity, making the system ideally suited for the simulation of dynamical phenomena. Here, we review three distinct time crystalline states, predicted and realized in a cavity-BEC system. We give an example for each of them, based on minimal few-mode models. We characterize the time crystalline states via correlation functions of the cavity mode, and characteristic momentum modes of the condensate. This supports a clear distinction between these time crystals. More generally, the sequence of studies reviewed here, serves as a blueprint for setting up minimal models and their characterization, for dynamical phenomena.

2605.23880 2026-05-25 hep-th gr-qc quant-ph

Not all black holes decohere quantum superpositions

并非所有黑洞都会使量子叠加退相干

Anna Biggs, Stefano Trezzi

AI总结 本文研究了近极限电荷黑洞对外部量子系统产生的退相干效应,特别分析了一个近期文献中讨论的思想实验,其中量子系统是一个处于空间叠加态的带电粒子。研究发现,当黑洞足够接近极限时,其近视界几何的量子度规涨落会导致退相干速率在晚期趋于消失,这一现象源于量子黑洞谱中的自旋诱导能量隙。尽管在能量高于该间隙时退相干速率非零,但其数值仍低于半经典预期,表明量子引力效应增强了叠加态的相干性。

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Comments
26 pages, 4 figures
AI中文摘要

我们研究了近极端带电黑洞对其外部量子系统诱导的退相干。具体来说,我们分析了文献中最近讨论的一个思想实验,其中量子系统是一个制备在空间叠加态的带电粒子。已知近极端黑洞在低温下表现出近视界几何的大量子度量涨落。我们证明,在晚期,如果黑洞足够接近极端,这些量子引力效应会使退相干速率消失。这种现象是由于量子黑洞谱中的自旋诱导能隙。对于高于能隙的能量,退相干速率变为非零,但仍相对于半经典预期被抑制,因此这些量子引力效应总是增强叠加的相干性。

英文摘要

We study the decoherence induced by near-extremal charged black holes on quantum systems in their exterior. Specifically, we analyze a thought experiment recently discussed in the literature, where the quantum system is a charged particle prepared in a spatial superposition. Near-extremal black holes are known to exhibit large quantum metric fluctuations of the near-horizon geometry at low temperatures. We show that, at late times, if the black hole is sufficiently close to extremality, these quantum gravity effects make the decoherence rate vanish. This phenomenon is due to a spin-induced energy gap in the quantum black hole spectrum. For energies above the gap, the decoherence rate becomes nonzero, but is still suppressed relative to semiclassical expectations, so these quantum gravity effects always enhance the coherence of the superposition.

2605.23877 2026-05-25 physics.flu-dyn q-bio.QM

Particle Image Velocimetry of 3D printed vascular fluidic phantom devices

3D打印血管流体仿体模型的粒子图像测速

Job van Essen, Ahmed Sharaf, Denzel Hopman, Selene Pirola, Paola Fanzio

AI总结 本研究提出了一种基于透明3D打印血管模型和粒子图像测速(PIV)技术的实验框架,用于研究微尺度脑血管中的血流动力学特性。通过构建具有正常和病理(如动脉瘤、狭窄)结构的微流体模型,结合微PIV技术测量局部速度场和壁面剪切应力,验证了该方法在捕捉关键流动特征和速度分布方面的可靠性。研究结果表明,该方法为探究微尺度脑血管血流动力学提供了稳定且有效的实验手段。

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AI中文摘要

血流动力学改变在动脉瘤和狭窄等脑血管疾病中起关键作用。然而,体内成像缺乏解决小血管中流动动力学所需的空间分辨率。本研究提出了一种实验框架,利用透明3D打印血管模型和粒子图像测速(PIV)研究微尺度血流动力学。通过增材制造制备了具有直管和病理(动脉瘤和狭窄)几何形状的光学透明微流控模型,最小直径达500微米,并使用光学显微镜进行表征。在稳态层流条件下进行流动实验,使用microPIV测量局部速度场和壁面剪切应力(WSS)。将测量速度与解析的Hagen-Poiseuille预测进行比较,平均相对误差为5%至17%。该平台可靠地捕捉了关键流动特征和速度的空间变化。总体而言,结果表明,透明3D打印血管模型结合microPIV为研究微尺度脑血管血流动力学提供了一种稳健的实验方法。

英文摘要

Altered hemodynamics play a key role in cerebrovascular diseases such as aneurysms and stenosis. However, in vivo imaging lacks the spatial resolution required to resolve flow dynamics in small vessels. This study presents an experimental framework to investigate microscale hemodynamics using transparent 3D printed vascular models and particle image velocimetry (PIV). Optically transparent microfluidic models with straight and pathological (aneurysmal and stenotic) geometries were fabricated via additive manufacturing up to a minimum diameter size of 500 microns and characterized using optical microscopy. Flow experiments were conducted under steady laminar conditions, and local velocity fields and wall shear stress (WSS) were measured using microPIV. Measured velocities have been compared with analytical Hagen Poiseuille predictions, obtaining mean relative errors of 5 to 17 percent. The platform reliably captured key flow features and spatial variations in velocity. Overall, the results demonstrate that transparent 3D printed vascular models combined with microPIV provide a robust experimental approach for studying microscale cerebrovascular hemodynamics.

2605.23876 2026-05-25 cond-mat.mtrl-sci

Photoluminescent Tetragonal Tb-doped Pb2P2O7

光致发光四方相Tb掺杂Pb2P2O7

Yong Liu, Wenhua Bi, Alla Arakcheeva, Arnaud Magrez

AI总结 本研究报道了一种新型四角晶系 Tb³⁺ 掺杂的 Pb₂P₂O₇ 材料的合成与表征。通过单晶 X 射线衍射确认了在室温下 P4₁ 和 P4₃ 对映异构体的稳定存在,归因于 Tb³⁺ 离子的引入。光学测试显示其具有绿色光致发光特性,发射光谱因晶体场效应而分裂,表明 Tb³⁺ 处于多种配位环境中。该材料在高温下表现出良好的结构稳定性,并显示出独特的温度依赖性发光行为,显示出其作为新型光致发光材料的潜力。

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AI中文摘要

在本研究中,我们报道了一种新型四方相Tb掺杂Pb2P2O7的合成与表征。单晶X射线衍射证实,由于Tb3+离子的掺入,在室温下稳定了P41和P43对映体。光学研究表明,来自Tb3+的特征5D4→7Fj(J=1-5)跃迁产生绿色光致发光,每个发射峰因晶体场效应而分裂,表明Tb3+存在于多种配位环境中。PL强度的功率依赖性遵循线性幂律行为,表明是单光子激发过程。温度相关的PL测量显示,强度在125°C之前初始增加,归因于结构缺陷的能量转移,随后在此温度以上发生热猝灭。通过高温X射线衍射(XRD)证实了高温下的结构稳定性,在约800°C熔化前未观察到相变。这些发现突出了四方相Tb掺杂Pb2P2O7作为新型光致发光材料的潜力。

英文摘要

In this study, we report the synthesis and characterization of a novel tetragonal polymorph of Tb-doped Pb2P2O7. Single-crystal X-ray diffraction confirms the stabilization of the P41 and P43 enantiomorphs at room temperature due to the incorporation of Tb3+ ions. Optical investigations reveal green photoluminescence from the characteristic 5D4 -> 7Fj (J = 1-5) transitions of Tb3+, with each emission split due to the crystal field effect, indicating the presence of Tb3+ in multiple coordination environments. The power dependence of the PL intensity follows a linear power-law behavior, suggesting a one-photon excitation process. Temperature-dependent PL measurements show an initial increase in intensity up to 125C, attributed to energy transfer from structural defects, followed by thermal quenching above this temperature. Structural stability at elevated temperatures is confirmed via high-temperature X-ray diffraction (XRD), showing no phase transitions before melting at approximately 800C. These findings highlight the potential of tetragonal Tb-doped Pb2P2O7 as a new class of photoluminescent material.

2605.23875 2026-05-25 physics.ao-ph

Atmosphere as a steam engine

大气作为蒸汽机

Anastassia Makarieva, Andrei Nefiodov

AI总结 本文将地球大气层视为一个蒸汽机,研究了水汽通过蒸发、膨胀、凝结和降水形成循环过程中的能量转换机制。通过推广克劳修斯-克拉佩龙方程,作者推导了单位降水水量的膨胀功,并考虑了抬升湿空气、凝结膨胀及不完全凝结的修正项。研究估算出全球蒸汽机功率约为4.4瓦/平方米,与大气总功率的独立估算值高度一致,揭示了凝结和降水在维持大气动力过程中的关键作用。

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Comments
33 pages, 8 figures, 2 tables
AI中文摘要

地球大气运行一个蒸汽循环,其中水蒸气从地表蒸发、膨胀、凝结并以降水形式返回。克劳修斯-克拉佩龙定律将饱和水蒸气的增量膨胀功与在对应于蒸发和凝结之间温差的卡诺效率下转换的潜热联系起来。我们将这一关系推广到凝结发生在一定高度范围内的气柱,并推导出每摩尔降水量的膨胀功。这包括将湿空气抬升到平均凝结高度相关的重力功、凝结产生的膨胀功以及不完全凝结的修正。利用GPCP v3.3降水和凝结高度的观测约束,我们估计全球蒸汽机功率为$W_v=4.4\pm0.9$ W/m2,接近独立估计的大气总功率$W=W_P+W_K\simeq4.3\pm0.6$ W/m2,后者由降水的重力功率和从MERRA-2诊断的水平压力梯度产生的动能得到。动能产生为$W_K\simeq3.2\pm0.3$ W/m2,其中至少三分之二产生于低层大气。较小的上层大气贡献(由温度相关的压力梯度主导)与洛伦兹有效位能产生相当。蒸汽机功率与大气功率之间的一致性归因于凝结和降水沉降。通过从大气气相中移除水并实现气柱质量再分布,降水维持了驱动摩擦低层大气中跨等压线流动的地表压力梯度。因此,蒸汽机框架为凝结诱导的大气动力学提供了热力学基础,并识别了与水相变相关的主要低层大气功率路径。

英文摘要

Earth's atmosphere operates a steam cycle in which water vapor evaporates from the surface, expands, condenses, and returns as precipitation. The Clausius-Clapeyron law relates the incremental expansion work of saturated water vapor to latent heat converted at a Carnot efficiency corresponding to the temperature difference between evaporation and condensation. We generalize this relation to an atmospheric column with condensation occurring over a range of heights and derive the expansion work per mole of precipitated water. This includes the gravitational work associated with lifting moist air to the mean condensation height, the expansion work generated by condensation, and a correction for incomplete condensation. Using GPCP v3.3 precipitation and observational constraints on condensation height, we estimate the global steam-engine power as $W_v=4.4\pm0.9$ W/m2, close to an independent estimate of total atmospheric power, $W=W_P+W_K\simeq4.3\pm0.6$ W/m2, obtained from the gravitational power of precipitation and kinetic energy generation by horizontal pressure gradients diagnosed from MERRA-2. Kinetic energy generation is $W_K\simeq3.2\pm0.3$ W/m2, of which at least two thirds is generated in the lower atmosphere. The smaller upper-atmospheric contribution, dominated by temperature-related pressure gradients, is comparable to Lorenz available potential energy generation. The agreement between steam-engine and atmospheric power is linked to condensation and precipitation fallout. By removing water from the atmospheric gas phase and enabling column-mass redistribution, precipitation maintains surface pressure gradients that drive cross-isobaric flow in the frictional lower atmosphere. The steam-engine framework thus provides a thermodynamic basis for condensation-induced atmospheric dynamics and identifies a major lower-atmospheric power pathway associated with water phase transitions.

2605.23873 2026-05-25 quant-ph cond-mat.quant-gas cond-mat.stat-mech cond-mat.str-el

Coherent dynamics in chaotic spin chains via interference-protected subspaces

混沌自旋链中通过干涉保护子空间的相干动力学

Aron Kerschbaumer, Jean-Yves Desaules, Maksym Serbyn

AI总结 该研究探讨了混沌自旋链中通过干涉保护子空间实现的相干动力学现象。作者提出了一类具有结构化子空间的自旋-1/2链模型,能够在高能量密度下支持非热化现象,如疤痕态、手性传播准粒子和近似拓扑边缘态。研究通过破坏性干涉保护的子空间解释了这些现象,并建立了定量泄漏理论,预测了哪些态能够保持相干性,同时提出了增强稳定性的方法,拓展了混沌系统中弱遍历性破坏的范围。

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8+4 pages, 6+1 figures
AI中文摘要

一般量子多体系统预期会热化,在局域观测量弛豫到平衡值的同时扰乱初始相干性。弱遍历性破缺通常与均匀态的量子多体疤痕相关,提供了具有长寿命相干性的罕见例外。我们引入一族局域自旋-1/2链,其具有一个结构化子空间,该子空间承载更广泛的非热现象,如疤痕、手性传播准粒子或近似拓扑边缘模。这些发生在高能量密度下的非热现象可以通过受相消干涉保护的结构化子空间来理解。我们发展了一种定量泄漏理论,预测哪些态保持相干性,并提出了通过诱导补子空间中的快速振荡来提高稳定性的方法。我们的框架连接了渐近疤痕、量子笼和母哈密顿量构造,并表明混沌系统中的弱遍历性破缺远不止于均匀初始态的复兴。

英文摘要

Generic quantum many-body systems are expected to thermalize, scrambling initial coherence while local observables relax to equilibrium values. Weak ergodicity breaking, often associated with quantum many-body scarring of homogeneous states, provides rare exceptions with long-lived coherence. We introduce a family of local spin-1/2 chains with a structured subspace that hosts a much broader range of nonthermal phenomena, such as scars, chirally propagating quasiparticles or approximate topological edge modes. These nonthermal phenomena happening at high energy densities can be understood via structured subspaces that are protected by destructive interference. We develop a quantitative leakage theory predicting which states retain coherence and suggest ways to improve the stability by inducing fast oscillations in the complement subspace. Our framework connects asymptotic scars, quantum cages, and parent-Hamiltonian constructions, and shows that weak ergodicity breaking in chaotic systems extends well beyond revivals of homogeneous initial states.

2605.23870 2026-05-25 physics.atom-ph physics.comp-ph

Vapor-Cell-Induced Uncertainty in Rydberg Atom Measurements via the Electric-Field Volume-Integral-Equation Method

基于电场体积积分方程法的蒸气室在里德伯原子测量中的不确定性分析

Martin Stumpf, William J. Watterson, Rajavardhan Talashila, Matt T. Simons, Alexandra Artusio-Glimpse, Lawrence Carslake, Tian Hong Loh, Christopher L. Holloway

AI总结 本研究利用体积积分方程方法分析了蒸汽池对基于里德伯原子传感器的电场测量所产生的电磁散射效应。通过计算蒸汽池内网格点上的电场分布,该方法在优化计算和统计不确定性分析中表现出较高的效率。研究比较了由蒸汽池引起的不确定性(如玻璃相对介电常数的不确定性或驻波形成)与原子光谱测量引起的不确定性(如原子偶极矩的不确定性),发现当蒸汽池尺寸小于半个波长时,玻璃相对介电常数的不确定性是主要来源,总不确定性约为3.5%,接近国家计量机构传统方法的最优水平,精确测量介电常数有望将不确定性降低至1%以下。

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AI中文摘要

借助体积积分方程法分析了蒸气室对基于里德伯原子的传感器进行电场测量时的电磁散射效应。与测量类似,该计算方法确定了蒸气室内网格点上的电场。其相对较高的计算效率使其适用于优化程序和统计不确定性研究。我们应用该方法比较了由于蒸气室存在引起的不确定性贡献,例如玻璃相对介电常数的不确定性或室内驻波形成,与原子光谱测量引起的不确定性,例如原子偶极矩的不确定性。对于尺寸小于半波长的蒸气室,主要不确定性来源来自玻璃相对介电常数的不确定性,导致总不确定性约为3.5%——与国家计量研究所使用传统场生成方法获得的最佳不确定性相当。精确的介电常数测量有可能进一步将测量不确定性降低到<1%。

英文摘要

Electromagnetic scattering effects of a vapor cell on electric-field measurements using Rydberg atom-based sensors are analyzed with the aid of the volume integral equation method. In a manner similar to measurement, this computational approach determines the electric field over grid points within the vapor cell. Its relatively high computational efficiency makes it suitable for use in optimization routines and statistical uncertainty studies. We apply this method to compare uncertainty contributions arising due to the presence of the vapor cell, such as uncertainty in the glass relative permittivity or standing wave formation inside the cell, to those arising from the atomic spectroscopic measurement, such as uncertainty in the atomic dipole moment. For vapor cell dimensions less than half a wavelength, the dominant uncertainty source arises from uncertainty in the glass relative permittivity, resulting in a total uncertainty of $\sim$3.5\% -- comparable to the best uncertainties obtained with traditional field generation methods at national metrology institutes. Precise permittivity measurements have the potential to further reduce measurement uncertainty to $<1$\%.

2605.23869 2026-05-25 physics.flu-dyn

Soft Mobility Theory

软体运动理论

Christophe Eloy

AI总结 该研究提出了“软体运动理论”,用于预测可变形物体在粘性流体中的运动与形变,解决了从微生物运动到软体微型机器人等广泛问题。通过引入虚拟功率原理和洛伦兹互易定理,研究建立了依赖于物体形变的广义坐标常微分方程,扩展了经典刚体运动理论。该理论应用于由弹性弹簧连接的相互作用球体系统,并通过梯度下降方法实现了高效的逆向设计,展示了在静止流和剪切流中优化软体游动器和设计软体“冲浪者”的应用。

详情
Comments
22 pages, 11 figures
AI中文摘要

预测可变形体在粘性流中的运动和变形是微生物运动到软体微型机器人等问题的核心,但现有框架要么针对特定问题,要么不适合逆设计。我们提出软体运动理论:将虚功率原理和洛伦兹互易定理应用于背景斯托克斯流中的超弹性体,得到关于物体广义坐标的依赖于构型的常微分方程。该软体运动方程扩展了经典刚体运动理论,其中运动、弹性、体力、流耦合张量均显式依赖于瞬时变形。我们将该框架特化到由弹性弹簧连接的水动力学相互作用球体组装体,使用Rotne-Prager-Yamakawa近似计算运动张量,并在静止和剪切流中的刚体和柔性体经典问题上进行验证。开源的JAX实现使整个模拟可端到端微分,从而实现高效的基于梯度的逆设计:作为概念验证,我们恢复了三球游泳者的渐近最优解,并设计了一个软体趋旋性“冲浪者”,该冲浪者利用被动变形在泰勒-格林流中比其刚性对应物上升更快。

英文摘要

Predicting how a deformable body moves and deforms in a viscous flow underlies problems ranging from microorganism locomotion to soft microrobotics, yet existing frameworks are either problem-specific or ill-suited to inverse design. We propose the soft mobility theory: applying the principle of virtual power and the Lorentz reciprocal theorem to a hyperelastic body in a background Stokes flow yields a configuration-dependent ordinary differential equation for the generalized coordinates of the body. This soft mobility equation extends classical rigid-body mobility theory in that the mobility, elastic, body-force, and flow-coupling tensors all depend explicitly on the instantaneous deformation. We specialize the framework to assemblies of hydrodynamically interacting spheres connected by elastic springs, using the Rotne-Prager-Yamakawa approximation to compute the mobility, and validate it on canonical problems spanning rigid and flexible bodies in quiescent and shear flows. An open-source JAX implementation makes entire simulations end-to-end differentiable. This allows efficient gradient-based inverse design: as proofs of concept, we recover the asymptotic optimum of a three-sphere swimmer and design a soft gyrotactic "surfer" that exploits passive deformation to ascend faster than its rigid counterpart in a Taylor-Green flow.

2605.23860 2026-05-25 physics.ins-det hep-ex

TCAD + Allpi$\text{x}^2$ Simulation study of MALTA2, a Depleted Monolithic Active Pixel Sensor for future tracking

TCAD + Allpi$\text{x}^2$ 对 MALTA2 的仿真研究:一种用于未来跟踪的耗尽型单片有源像素传感器

L. Li, P. Behera, D. V. Berlea, D. Bortoletto, C. Buttar, T. Chembakan, V. Dao, G. Dash, Y. Enari, L. Fasselt, S. Haberl, T. Inada, F. K. Isik, C. Issever, X. Li, Y. Okazaki, H. Pernegger, P. Riedler, W. Snoeys, C. A Solans Sanchez, A. Swoboda, I. Turk Cakir, M. van Rijnbach, A. Vijay, S. Worm

AI总结 本文提出了一种结合TCAD和Allpix²的混合仿真框架,用于研究未来跟踪应用中耗尽型单片活性像素传感器MALTA2的性能。通过TCAD进行三维建模和瞬态仿真,获得掺杂分布和电场信息,并输入Allpix²进行高统计量的蒙特卡洛仿真,分析其在单探测器和全望远镜模式下的表现。研究发现传感器的探测效率和簇尺寸强烈依赖于传感器表面N型覆盖层的掺杂浓度,并通过与实验数据对比优化了该浓度。仿真与测量结果在活性区域深度方面达成良好一致,偏差仅为2%,验证了该框架在传感器研究中的通用性和有效性。

详情
Comments
21 pages, 15 figures
AI中文摘要

在这项工作中,提出了一个结合 TCAD 和 Allpi$\text{x}^2$ 的混合仿真框架,以研究 MALTA2(一种为未来跟踪设计的耗尽型单片有源像素传感器)的传感器特性。研究从 TCAD 中的三维建模和瞬态仿真开始,采用通用掺杂分布和简单阱结构。提取得到的掺杂分布和电场被输入到 Allpi$\text{x}^2$ 中,用于在仅被测器件模式和全望远镜模式下进行高统计蒙特卡罗模拟。 模拟揭示了传感器性能(特别是探测效率和簇大小)对传感器表面 N 型覆盖层掺杂浓度的强烈依赖性。然后通过将模拟与测量数据进行比较来优化掺杂浓度。使用掠射角方法在模拟和测量中估计了 MALTA2 传感器耗尽区的活性深度,该方法将传感器相对于束流放置在不同的倾角下,覆盖从 0 到 60 度的角度。在最佳掺杂浓度下,活性深度与测量值吻合良好,在 450 $\text{e}^-$ 阈值下偏差为 2%。因此,该框架为传感器研究提供了一个通用工具包,无需专有信息。

英文摘要

In this work, a hybrid simulation framework combining TCAD and Allpi$\text{x}^2$ is presented to investigate the sensor properties of MALTA2, a depleted monolithic active pixel sensor designed for future tracking. The study starts from 3D modeling and transient simulations in TCAD, with generic doping profiles and simple well structures. The resulting doping profiles and electric field are extracted and fed into Allpi$\text{x}^2$ for high-statistics Monte Carlo simulations in both DUT-only and full-telescope mode. Simulations reveal a strong dependence of sensor performance, specifically the detection efficiency and cluster size, on the doping concentration of the N-type blanket at the sensor surface. The doping concentration is then optimized by comparing simulations with measurement data. The active depth of the depleted region of the MALTA2 sensor is estimated in both simulations and measurements using a grazing angle method, in which the sensor is positioned at various inclinations relative to the beam, covering angles from 0 to 60 degrees. Excellent agreement on active depth is obtained with the optimal doping concentration, showing a deviation of 2\% from the measured value at a threshold of 450\,$\text{e}^-$. Consequently, the framework offers a generic toolkit for sensor studies without requiring proprietary information.

2605.23855 2026-05-25 cond-mat.mtrl-sci

Phase-dependent electronic structure of two-dimensional Ag layers at the graphene/SiC interface

石墨烯/SiC界面二维银层的相依赖电子结构

Sawani Datta, Boyang Zheng, Arpit Jain, Kathrin Küster, Joshua A. Robinson, Vincent H. Crespi, Ulrich Starke

AI总结 本研究探讨了在石墨烯/SiC界面处插入的二维银层的相依赖性电子结构。通过原位超高真空制备方法,获得了与SiC晶格旋转30度的高密度Ag$_{(2)}$相,并利用低能电子衍射和角分辨光电子能谱揭示了其更丰富的能带结构。理论计算表明,Ag$_{(2)}$的能带结构更适合展开到SiC原胞,且其对石墨烯层的电荷载流子密度和电荷-等离子体相互作用具有显著影响,显示出界面电子性质的调控潜力。

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Comments
13 pages, 7 figures, Supplementary information is in the ancillary file
AI中文摘要

石墨烯/SiC界面的插层提供了一种可控途径来稳定原子级薄层,其性质与块体对应物不同。在该平台中,插层相的结构和稳定性敏感地依赖于起始衬底的缺陷景观。对于石墨烯/SiC界面插层的二维银,已观察到两个相:一个与SiC晶格外延的相Ag$_{(1)}$,可通过超高真空条件下的常规插层方法轻松获得并得到广泛表征;另一个更密集堆积的相称为Ag$_{(2)}$,此前尚未被充分探索。本文报道了一种原位超高真空制备方法,用于在石墨烯/SiC界面制备第二种插层相;该相先前是通过高压限制异质外延制备的。低能电子衍射显示,Ag$_{(2)}$相对于SiC晶格旋转30度并形成超胞,而Ag$_{(1)}$与SiC呈$(1\times 1)$外延关系。高分辨率角分辨光电子能谱揭示Ag$_{(2)}$比Ag$_{(1)}$具有更丰富的能带色散。在密度泛函理论计算中,通过定义展开熵,以量化方式发现Ag$_{(2)}$的能带结构更适合展开到SiC原胞,且展开后的能带色散与实验数据高度一致。我们进一步表明,不同的插层Ag相以不同方式调控上方准自由站立石墨烯层的电子性质:与Ag$_{(1)}$相比,Ag$_{(2)}$产生约1.75倍的更高载流子密度,并改变石墨烯层的电荷-等离子体相互作用,表明界面有效屏蔽发生变化。

英文摘要

Intercalation at the graphene/SiC interface provides a controlled route to stabilize atomically thin layers with properties distinct from their bulk counterparts. In this platform, the structure and stability of the intercalated phase depend sensitively on the defect landscape of the starting substrate. For intercalated two-dimensional silver at the graphene/SiC interface, two phases have been observed: a phase epitaxial to the SiC lattice, Ag$_{(1)}$, readily obtained following the conventional intercalation method under ultra-high-vacuum conditions and extensively characterized, and a more densely packed phase, called Ag$_{(2)}$, which has remained largely unexplored. Here we report an in situ ultra-high-vacuum preparation method of the second phase intercalated at the graphene/SiC interface; this phase previously was prepared via high-pressure confinement heteroepitaxy. Low-energy electron diffraction shows that Ag$_{(2)}$ is rotated by 30 degree relative to the SiC lattice and forms supercells, in contrast to the $(1\times 1)$ epitaxial relation of Ag$_{(1)}$ with SiC. High-resolution angle-resolved photoemission spectroscopy reveals a more rich Ag$_{(2)}$ band dispersion compared to the Ag$_{(1)}$. In density functional theory calculations, by defining the unfolding entropy which, in a quantified way, finds that the band structure of Ag$_{(2)}$ is more suitable to be unfolded to the SiC primitive cell, and the resulting unfolded band dispersion is in great agreement with the experimental data. We further show that the different intercalated Ag phases tune the electronic properties of the overlying quasi-free-standing graphene layer differently: compared with Ag$_{(1)}$, Ag$_{(2)}$ yields an $\sim$1.75 times higher charge carrier density and modifies the charge-plasmon interaction of the graphene layer, indicating a change in effective screening at the interface.

2605.23853 2026-05-25 math-ph math.MP physics.optics quant-ph

Exact versus tight-binding models in longitudinally modulated $\mathcal{PT}$-symmetric coupled waveguides

纵向调制 $\mathcal{PT}$ 对称耦合波导中的精确模型与紧束缚模型

Alonso Contreras-Astorga, José Israel Galindo-Rodríguez

AI总结 本文研究了纵向调制的$\mathcal{PT}$-对称耦合波导系统中紧束缚(TB)模型与精确解之间的差异。通过构建基于超对称变换的精确连续模型,并与对应的离散TB近似进行对比分析,揭示了TB模型在再现空间强度分布方面的有效性,同时指出了其在描述非厄米演化中复杂振荡相位动力学方面的局限性。研究明确了TB模型在该类系统中的适用范围,为相关理论与应用提供了重要参考。

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AI中文摘要

紧束缚(TB)模型是描述波导阵列中光传播的广泛采用的近似方案。尽管其成功,但在以强纵向调制为特征的 $\mathcal{PT}$ 对称系统中,其有效性尚未通过精确解析解进行严格基准测试。在这项工作中,我们通过比较从 $z$ 依赖的超对称(SUSY)变换导出的精确连续解及其相应的离散 TB 近似来填补这一空白。为此,我们为两个受纵向调制的 PT 对称耦合波导开发了一个理论模型。然后,我们针对精确的 SUSY 基准评估了 TB 框架的性能。我们的结果描绘了 TB 近似的具体有效范围,展示了其在再现空间强度分布方面的能力。然而,我们也识别了其在准确捕捉这种非厄米演化中固有的复杂振荡相位动力学方面的局限性。

英文摘要

The tight-binding (TB) model is a widely adopted approximation scheme for describing light propagation in waveguide arrays. Despite its success, its validity in $\mathcal{PT}$-symmetric systems characterized by strong longitudinal modulation has not been rigorously benchmarked against exact analytical solutions. In this work, we address this gap by performing a comparative analysis between exact continuous solutions derived from $z$-dependent supersymmetric (SUSY) transformations and their corresponding discrete TB approximations. To achieve this, we develop a theoretical model for two PT-symmetric coupled waveguides subject to longitudinal modulation. We then evaluate the performance of the TB framework against the exact SUSY benchmark. Our results delineate the specific validity range of the TB approximation, demonstrating its proficiency in reproducing spatial intensity distributions. However, we also identify its limitations in accurately capturing the complex oscillatory phase dynamics inherent to this non-Hermitian evolution.

2605.23852 2026-05-25 quant-ph math-ph math.MP

Convexity and non-Markovianity of Weyl Maps

Weyl映射的凸性与非马尔可夫性

Wen Xu, Vinayak Jagadish

AI总结 本文研究了由Weyl动力映射及其凸组合所描述的有限维开放量子系统中非马尔可夫动力学的出现机制。通过赫米特标准型,作者建立了离散相空间子群的完整分类,构建了Weyl映射的代数框架,并分析了各向同性和各向异性Weyl映射在生成马尔可夫半群和非马尔可夫记忆效应中的不同行为。研究还揭示了凸组合在非马尔可夫性生成与抑制中的作用,并证明了非马尔可夫性在混合过程中不具有可加性,同时发现了无需混合即可表现出永恒非马尔可夫性的不可约Weyl退相干映射,拓展了非马尔可夫动力学理论在Pauli框架之外的适用范围。

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Comments
17 pages
AI中文摘要

我们研究了由Weyl动力学映射及其凸组合支配的有限维开放量子系统中非马尔可夫动力学的出现。利用Hermite标准型,我们提供了离散相空间$\mathbb{Z}_d imes \mathbb{Z}_d$子群的完全分类,建立了Weyl映射背后的代数框架。我们刻画了生成马尔可夫半群的各向同性Weyl动力学映射,并表明具有非均匀权重分布的各向异性Weyl映射不能具有半群性质。此外,我们分析了凸性在记忆效应产生和抑制中的作用。值得注意的是,我们证明了永恒非马尔可夫Weyl退相映射的凸组合可以生成马尔可夫半群,表明非马尔可夫性在混合下不可加。相反,我们建立了一个一般条件,在该条件下$N$个不同Weyl半群的凸混合表现出永恒非马尔可夫性。与量子比特Pauli设置相比,我们进一步识别了不可约的永恒非马尔可夫Weyl退相映射的存在,即无需任何混合机制即可显示永恒记忆效应的单个动力学映射。最后,显式的qutrit例子说明了马尔可夫、非马尔可夫和永恒非马尔可夫区域之间的转变。我们的结果揭示了有限相空间代数、凸结构和量子记忆效应之间的基本联系,从而将非马尔可夫动力学理论扩展到Pauli框架之外。

英文摘要

We investigate the emergence of non-Markovian dynamics in finite-dimensional open quantum systems governed by Weyl dynamical maps and their convex combinations. Using the Hermite normal form, we provide a complete classification of the subgroups of the discrete phase space $\mathbb{Z}_d \times \mathbb{Z}_d$, establishing the algebraic framework underlying the Weyl maps. We characterize isotropic Weyl dynamical maps that generate Markovian semigroups and show that anisotropic Weyl maps with nonuniform weight distributions cannot possess the semigroup property. Furthermore, we analyze the role of convexity in the generation and suppression of memory effects. Remarkably, we prove that convex combinations of eternally non-Markovian Weyl dephasing maps can generate Markovian semigroups, demonstrating that non-Markovianity is not additive under mixing. Conversely, we establish a general condition under which convex mixtures of $N$ distinct Weyl semigroups exhibit eternal non-Markovianity. In contrast to the qubit Pauli setting, we further identify the existence of irreducible eternally non-Markovian Weyl dephasing maps, namely, individual dynamical maps that display eternal memory effects without requiring any mixing mechanism. Finally, explicit qutrit examples illustrate the transition among Markovian, non-Markovian and eternally non-Markovian regimes. Our results uncover a fundamental connection among finite phase-space algebra, convex structures, and quantum memory effects, thereby extending the theory of non-Markovian dynamics beyond the Pauli framework.

2605.23848 2026-05-25 hep-th cond-mat.quant-gas

A new Ising/tricritical-Ising interface: From ${W}_3$ symmetry to Rydberg atoms

一个新的Ising/三临界Ising界面:从${W}_3$对称性到里德伯原子

António Antunes, Junchen Rong

AI总结 本文研究了不同普适类临界自旋链之间的界面,提出了一个新的介于三临界伊辛(TIM)和伊辛共形场论(CFT)之间的共形界面,并揭示了其在里德伯原子阵列中的潜在实验实现。研究强调非可逆对称性与模变换下的一致性,利用缺陷耦合和缺陷谱(包括混合边界条件)提出了明确的实验预测,核心在于发现了该界面所具有的新兴${W}_3$手征对称性结构。

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Comments
6 pages, 6 figures, 4 appendices
AI中文摘要

我们考虑不同普适类中临界自旋链之间的界面,在连续极限下由缺陷/界面共形场论(DCFT/ICFT)描述。我们发现三临界Ising模型(TIM)与Ising CFT之间的一个新共形界面。我们还探讨了其在里德伯原子阵列中实验实现的可能性。我们的分析强调了非可逆对称性和模变换下的一致性,并利用缺陷耦合和缺陷谱(包括混合边界条件的情况)做出清晰的实验预测。可观测量的结构依赖于新发现的用于三临界Ising/Ising界面的涌现${W}_3$手征对称性模式。

英文摘要

We consider interfaces between critical spin-chains in different universality classes, described in the continuum limit by defect/interface conformal field theory (DCFT/ICFT). We find a new conformal interface between the Tricritical Ising (TIM) and the Ising CFT. We also explore the possibility of its experimental realizations in the context of Rydberg atom arrays. Our analysis emphasizes non-invertible symmetries and consistency under modular transformations, and uses defect couplings and the defect spectrum -- including in the case of mixed boundary conditions -- to make sharp experimental predictions. The structure of the observables hinges on a newly discovered pattern of emergent ${W}_3$ chiral symmetry for the Tricritical-Ising/Ising interface.

2605.23842 2026-05-25 hep-th gr-qc

Dissipative non-Abelian fluids from Scherk-Schwarz dimensional reduction

通过Scherk-Schwarz维度约化的耗散非阿贝尔流体

Emilio Torrente-Lujan

AI总结 本文通过Scherk-Schwarz维数约化方法,从高维的中性粘性共形流体出发构造了一个$d$维的耗散非阿贝尔流体模型。高维应力张量的非对角分量在约化后成为非阿贝尔颜色电流,而高维剪切张量则诱导出剪切、体模和矢量耗散结构。研究推导了状态方程、声速、颜色电流、熵流及一阶输运系数的映射关系,并详细讨论了约化过程中引起的流体力学框架问题、内部快度场的作用以及热力学第二定律在约化理论中的传递机制。该构造为非阿贝尔耗散流体力学提供了一个理论模型,具有在强相互作用物质如夸克-胶子等离子体中应用的潜力。

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AI中文摘要

我们通过在$D=d+n$维的中性粘性共形流体在$n$维单模群流形上的Scherk-Schwarz约化,构造了一个$d$维耗散有色流体。高维应力张量的非对角分量变为非阿贝尔色流,而高维剪切张量在约化理论中诱导出剪切、类体粘性和矢量耗散结构。我们推导了状态方程、声速、色流、熵流和一阶输运系数的映射。特别地,\[ η=e^{αφ}\coshξ\,\heta,\qquad τ=η\, rac{n}{(D-1)(d-1)},\qquad κ=η\sinh^2ξ. \] 我们还阐述了由维度约化引起的流体动力学框架问题,讨论了内部快度场$ξ$的状态,并详细说明了第二定律如何从母理论降下来,包括温度依赖的粘性、非单模群以及$ξ$的可能选择所起的作用。该构造应被视为非阿贝尔耗散流体动力学的玩具模型,有可能为直接现象学模型(例如夸克-胶子等离子体)铺平道路。

英文摘要

We construct a $d$-dimensional dissipative colored fluid by Scherk--Schwarz reduction of a neutral viscous conformal fluid in $D=d+n$ dimensions on an $n$-dimensional unimodular group manifold. The off-diagonal components of the higher-dimensional stress tensor become non-Abelian color currents, while the higher-dimensional shear tensor induces shear, bulk-like and vector-dissipative structures in the reduced theory. We derive the map for the equation of state, sound speed, color current, entropy current and first-order transport coefficients. In particular, \[ η=\ee^{αφ}\coshξ\,\heta,\qquad τ=η\,\frac{n}{(D-1)(d-1)},\qquad κ=η\sinh^2ξ. \] We also spell out the hydrodynamic-frame issue induced by dimensional reduction, discuss the status of the internal rapidity field $ξ$, and give a detailed account of how the second law descends from the parent theory, including the roles of temperature-dependent viscosity, non-unimodular groups and possible choices for $ξ$. The construction should be regarded as a toy model for non-Abelian dissipative hydrodynamics with the potential of paving the way to direct phenomenological model of, for example, quark--gluon plasma.

2605.23841 2026-05-25 astro-ph.CO astro-ph.IM

cloelike: A Python Library for Cosmological Likelihood Inference in the Euclid Era

cloelike: 一个用于欧几里得时代宇宙学似然推断的Python库

Marco Bonici, Guadalupe Cañas-Herrera, Pedro Carrilho, Santiago Casas, Chiara Moretti, Andrea Pezzotta, Zahra Baghkhani, Carmelita Carbone, Martin Crocce, Jip de Buck, Klara Bertmann, Nastassia Grimm, Martin Kärcher, Felicitas Keil, Davide Sciotti, Peter L. Taylor, Nicolas Tessore, Isaac Tutusaus, Casper Vedder

AI总结 cloelike 是一个用于欧几里得时代宇宙学似然推断的 Python 库,提供模块化且可组合的高斯似然类,支持欧几里得任务主要的宇宙学大尺度结构观测量。该库实现了包括弱透镜、光谱星系团聚类和星系-星系透镜等多种观测手段的高斯似然计算,并与理论预测和数据读取模块直接接口,是 CLOE 生态系统的核心组件。该工具已被用于欧几里得联盟的内部分析,并向社区开放以支持验证与结果复现。

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AI中文摘要

cloelike是一个Python包,为ESA欧几里得空间任务的主要宇宙学大尺度结构观测量提供模块化、可组合的高斯似然类。它是CLOE(欧几里得观测量宇宙学似然)生态系统的核心组件,直接与cloelib接口进行理论预测,并与euclidlib接口读取官方欧几里得数据产品。该包实现了涵盖弱引力透镜(WL)、测光星系成团性(GCph)和星系-星系透镜(GGL)的所有联合探针组合(3x2pt, 2x2pt)的谐波角功率谱和实空间两点相关函数,以及光谱全形功率谱多极和重子声学振荡(BAO)的高斯似然。cloelike被积极用于欧几里得联盟内部分析,并公开发布以支持社区验证和可重复性。

英文摘要

cloelike is a Python package providing modular, composable Gaussian likelihood classes for the main cosmological large-scale structure observables targeted by the ESA Euclid space mission. It is a core component of the CLOE (Cosmology Likelihood for Observables in Euclid) ecosystem and interfaces directly with cloelib for theoretical predictions and euclidlib for reading official Euclid data products. The package implements Gaussian likelihoods covering harmonic angular power spectra and real-space two-point correlation functions for weak lensing (WL), photometric galaxy clustering (GCph), and Galaxy-Galaxy Lensing (GGL) in all joint probe combinations (3x2pt, 2x2pt), as well as spectroscopic full-shape power spectrum multipoles, and baryonic Acoustic oscillations (BAO). cloelike is actively used in internal Euclid Consortium analyses and is openly released to support community validation and reproducibility.

2605.23839 2026-05-25 astro-ph.CO astro-ph.IM

cloelib: A Flexible Python Library for Computing Cosmological Observables in the Euclid Era

cloelib: 一个用于计算欧几里得时代宇宙学可观测量的灵活Python库

Marco Bonici, Guadalupe Cañas-Herrera, Pedro Carrilho, Santiago Casas, Chiara Moretti, Andrea Pezzotta, Michel Aguena, Giovanni Aricó, Zahra Baghkhani, Matteo Baratto, Emilio Bellini, Jip de Buck, Klara Bertmann, Ben Bose, Jeger C. Broxterman, Pierre Burger, Carmelita Carbone, Chaitanya Chawak, Jose Coloma-Nadal, Martin Crocce, Stefano Davini, Christopher A. J. Duncan, Samuel Farrens, Lisa Goh, Nastassia Grimm, Alex Hall, Ryusei R. Kano, Martin Kärcher, Felicitas Keil, Raphaël Kou, Laila Linke, Arthur Loureiro, Katarina Markovic, David Navarro-Gironés, Filippo Oppizzi, Gabriele Parimbelli, Anna Porredon, Robert Reischke, Jaime Ruiz Zapatero, Iñigo Sáez-Casares, Ziad Sakr, Neel Shah, Davide Sciotti, Matthieu Schaller, Ivan Sladoljev, Arghavan Souki, Sankarshana Srinivasan, Konstantinos Tanidis, Peter L. Taylor, Nicolas Tessore, Linus Thummel, Maria Tsedrik, Isaac Tutusaus, Casper Vedder, Angus H. Wright, Miguel Zumalacárregui, Joe Zuntz

AI总结 cloelib 是一个用于计算欧几里得任务(Euclid)时代宇宙学观测量的灵活 Python 库,旨在满足新一代宇宙学推断流程对高效、可微分软件的需求。该库采用模块化架构,与主流玻尔兹曼求解器兼容,并基于 JAX 实现自动微分,支持梯度下降等优化方法。它定义了统一的背景演化、扰动和非线性结构形成协议,支持多种观测量计算,计划作为欧几里得任务首个宇宙学发布的核心理论计算基础设施。

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AI中文摘要

cloelib是一个Python库,旨在欧几里得宇宙学可观测量似然(CLOE)生态系统(cloe-org)中计算宇宙学可观测量。随着宇宙学进入由欧几里得等星系巡天任务驱动的精确时代,对能够支持下一代推断管道的灵活、高效且可微软件的需求日益增长。cloelib通过模块化架构满足这些需求,该架构与成熟的玻尔兹曼求解器无缝对接,同时集成基于JAX的自动微分以支持梯度方法。该库定义了背景演化、扰动和非线性结构形成的一致协议,并支持广泛的可观测量,包括测光和光谱大尺度结构探针,以及与宇宙微波背景和星系团的交叉关联。在其最终形式中,cloelib旨在作为欧几里得首次宇宙学发布的参考理论计算基础设施,连接传统数值宇宙学与现代优化技术及新兴的机器学习推断方法。

英文摘要

cloelib is a Python library developed to compute cosmological observables within the Cosmology Likelihood for Observables in Euclid (CLOE) ecosystem (cloe-org). As cosmology enters a precision era driven by galaxy survey missions such as Euclid, there is a growing need for flexible, efficient, and differentiable software capable of supporting next-generation inference pipelines. cloelib addresses these demands through a modular architecture that interfaces seamlessly with established Boltzmann solvers whilst incorporating JAX-based automatic differentiation to enable gradient-based methods. The library defines consistent protocols for background evolution, perturbations, and non-linear structure formation, and supports a wide range of observables, including photometric and spectroscopic large-scale structure probes, as well as cross-correlations with the Cosmic Microwave Background and galaxy clusters. In its finalised form, cloelib is intended to serve as the reference theory computation infrastructure for Euclid's first cosmological release, bridging traditional numerical cosmology with modern optimisation techniques and emerging machine learning approaches to inference.

2605.23838 2026-05-25 cond-mat.supr-con cond-mat.mes-hall

Quantum critical collapse of a pinned vortex glass

钉扎涡旋玻璃的量子临界坍缩

David Perconte, Thibault Charpentier, Nikolaos Koutsopoulos, Kalpajit Roy, Nadjib Benchabane, Xiaoli Peng, Florent Blondelle, Frédéric Gay, Mikhail Feigel'man, Viktor Kabanov, Benjamin Sacépé

AI总结 本研究探讨了强无序超导体在磁场作用下,无序与涡旋间相互作用如何稳定出一种具有强钉扎特性的涡旋玻璃态,并研究其在磁场驱动的超导-绝缘体相变中的作用。通过微波光谱实验,研究人员发现超流密度在临界磁场附近表现出异常缓慢的衰减行为,这一现象归因于涡旋间相互作用增强的集体钉扎机制。研究还揭示了涡旋玻璃态在临界点附近表现出连续的量子临界行为,并具有显著的非线性电磁响应,为量子传感等应用提供了新途径。

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Maintext and SI
AI中文摘要

强无序超导体中,无序与涡旋-涡旋相互作用的竞争可以稳定涡旋玻璃态,其特征是强钉扎和缺乏位置有序。然而,它在磁场驱动的超导体-绝缘体转变中破坏超导电性的作用尚未明确。这里,我们利用非晶氧化铟薄膜制成的超导谐振器的等离子体微波光谱学,直接追踪超流密度直至临界场$B_c$。我们发现超流密度出人意料的韧性,在近三个数量级的磁场范围内仅呈对数下降,这与涡旋晶格预期的快速幂律抑制形成鲜明对比。我们将这种异常缓慢的衰减归因于一种集体涡旋钉扎机制,该机制反直觉地被涡旋-涡旋相互作用增强。随后,超流密度在$B_c$处线性消失,独立的磁电阻测量在此处识别出一个连续的量子临界点,与零场下观察到的突变转变不同。我们进一步揭示了涡旋玻璃异常大的非线性电磁响应,表现为显著的正Kerr效应,具有量子传感的潜力。这些结果展示了无序如何控制临界磁场,并将涡旋玻璃确定为控制磁场诱导超导体-绝缘体转变的关键中间态。

英文摘要

The interplay between disorder and vortex--vortex interactions in strongly disordered superconductors in a magnetic field can stabilize a vortex-glass state, characterized by strong pinning and the absence of positional order. Yet its role in the destruction of superconductivity at the field-driven superconductor--insulator transition has remained unresolved. Here we use plasmonic microwave spectroscopy of superconducting resonators patterned from amorphous indium oxide thin films to directly track the superfluid density up to the critical field $B_c$. We find an unexpected resilience of the superfluid density, which decreases only logarithmically over nearly three orders of magnitude in field, in stark contrast to the rapid power-law suppression expected for vortex lattices. We attribute this anomalously slow decay to a collective vortex-pinning mechanism counterintuitively enhanced by vortex--vortex interactions. The superfluid density then vanishes linearly at $B_c$, where independent magnetoresistance measurements identify a continuous quantum critical point, unlike the abrupt transition observed at zero field. We further uncover an exceptionally large nonlinear electromagnetic response of the vortex glass, manifested as a pronounced positive-Kerr effect with potential for quantum sensing. These results show how disorder controls the critical magnetic field and identify the vortex glass as the key intermediate state governing the magnetic-field-induced superconductor--insulator transition.

2605.23836 2026-05-25 cond-mat.mes-hall

Orbital Selective Dirac-like States in EuAgAs Revealed by Polarization Dependent ARPES and DFT

极化依赖ARPES和DFT揭示EuAgAs中的轨道选择性狄拉克态

Mohit Mudgal, Suman Nandi, Mohamed El Gazzah, Masashi Arita, Shin-ichiro Ideta, Nirmal J. Ghimire, Kenya Shimada, Anup Pradhan Sakhya

AI总结 该研究通过偏振依赖角分辨光电子能谱(ARPES)和密度泛函理论(DFT)方法,系统研究了磁性拓扑狄拉克半金属候选材料EuAgAs的电子结构和轨道特性。实验观测到近线性狄拉克型能带色散,并揭示了费米面和常能面随结合能增加而扩展的环状特征,与DFT计算预测的范霍夫奇异点一致。研究还发现电子态的轨道贡献具有对称性选择性,且狄拉克态在较宽温度范围内保持稳定,表明磁序对电子结构影响较小,为理解磁性拓扑量子态提供了重要线索。

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AI中文摘要

磁性拓扑半金属为磁性与相对论性费米子相互作用驱动的新兴量子现象(包括反常输运效应和可调拓扑相)提供了有前景的平台。本文利用密度泛函理论(DFT)和极化依赖角分辨光电子能谱(ARPES)研究了磁性拓扑狄拉克半金属候选材料EuAgAs的电子结构和轨道特性。在9 eV下测量的费米面映射和等能轮廓揭示了环状特征,这些特征随结合能增加而系统性地扩展,与近线性的低能狄拉克色散一致。不同光子能量下的ARPES测量暗示了DFT计算预测的范霍夫奇点的存在。此外,这表明光发射矩阵元对激发能量高度敏感,使得不同光子能量能够选择性地探测不同的轨道特征。在s和p偏振几何下进行的极化依赖ARPES测量显示出光谱强度的显著变化,表明电子态具有对称性选择的轨道贡献。这些由矩阵元驱动的强度调制被DFT计算很好地重现。此外,观察到的狄拉克态在9 K至30 K的温度范围内几乎保持不变,表明磁有序对电子结构影响极小。我们的实验与理论结合的结果提供了对EuAgAs轨道选择性电子结构及其对磁性拓扑量子态影响的详细见解。

英文摘要

Magnetic topological semimetals provide a promising platform for emergent quantum phenomena driven by the interplay between magnetism and relativistic fermions, including anomalous transport effects and tunable topological phases. Here, we investigate the electronic structure and orbital character of EuAgAs, a magnetic topological Dirac semimetal candidate, using density functional theory (DFT) and polarization dependent angle resolved photoemission spectroscopy (ARPES). Fermi surface mapping and constant energy contours measured at 9 eV reveal ring like features that systematically expand with increasing binding energy, consistent with nearly linear low energy Dirac like dispersion. ARPES measurements at different photon energies hint at the presence of a van Hove singularity predicted by DFT calculations. Furthermore, this indicates that the photoemission matrix elements are highly sensitive to the excitation energy, allowing different photon energies to selectively probe distinct orbital characters. Polarization dependent ARPES measurements performed in s- and p-polarized geometries exhibit pronounced variations in spectral intensity, indicating symmetry selective orbital contributions to electronic states. These matrix element driven intensity modulations are well reproduced by DFT calculations. Furthermore, the observed Dirac like states remain nearly unchanged over the temperature range from 9 K to 30 K, suggesting that the magnetic ordering has minimal influence on the electronic structure. Our combined experimental and theoretical results provide detailed insight into the orbital selective electronic structure of EuAgAs and its implications for magnetic topological quantum states.

2605.23834 2026-05-25 hep-th gr-qc hep-ph

Thermodynamics and transport in holographic QCD with Gauss-Bonnet corrections

高西-邦内修正的全息QCD中的热力学与输运

ChenWei Tong, Jie Zhou, YuanXu Wang, Rong-Gen Cai, Song He, Li Li

AI总结 本文研究了包含高斯-玻纳修正的全息QCD模型中的热力学和输运性质,通过最先进格点QCD热力学数据确定模型参数。研究分析了零及有限重子化学势下的状态方程、温度与化学势平面上的相结构,以及剪切粘滞系数与熵密度比η/s和体积粘滞系数与熵密度比ζ/s。当高斯-玻纳耦合为常数时,模型能合理描述状态方程,但η/s在临界区域附近仍保持单调,与经验预期不符;而当高斯-玻纳耦合依赖标量场时,可得到非单调的η/s和峰值ζ/s,并保持热力学一致性,所得相图在经验相关区域内包含临界端点。

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35 pages, 11 figures
AI中文摘要

在一个全息QCD模型中研究了热力学和输运性质,该模型通过引入高西-邦内修正扩展了爱因斯坦-麦克斯韦-狄拉顿框架。利用最先进的格点QCD热力学固定模型参数。然后分析考察了零和有限重子化学势下的状态方程、温度和化学势平面上的相结构,以及通过相应的涨落方程得到的剪切和体粘滞系数与熵密度比η/s和ζ/s。对于常数高西-邦内耦合,模型保留了状态方程的合理描述,并产生温度依赖的η/s,尽管所得轮廓在交叉区域附近仍是单调的,这不符合现象学期望。当允许高西-邦内耦合依赖于狄拉顿时,在保持与热力学约束一致的同时,得到了非单调的η/s和峰状的ζ/s。所得相图包含一个位于现象学相关区域的临界端点。

英文摘要

Thermodynamics and transport are investigated in a holographic QCD model that extends the Einstein--Maxwell--Dilaton framework by incorporating Gauss--Bonnet corrections. Model parameters are fixed using state-of-the-art lattice QCD thermodynamics. The analysis then examines the equation of state at zero and finite baryon chemical potential, the phase structure in the temperature and chemical potential plane, as well as the shear and bulk viscosity to entropy ratios, $η/s$ and $ζ/s$, via the corresponding fluctuation equations. For a constant Gauss--Bonnet coupling, the model preserves a reasonable description of the equation of state and generates a temperature-dependent $η/s$, although the resulting profile remains monotonic near the crossover region, which does not satisfy the phenomenological expectation. When the Gauss--Bonnet coupling is allowed to depend on the dilaton, a non-monotonic $η/s$ and a peaked $ζ/s$ are obtained while maintaining agreement with thermodynamic constraints. The resulting phase diagram contains a critical end point in a phenomenologically relevant region.

2605.23827 2026-05-25 gr-qc astro-ph.CO hep-ph

Natural Metric-Affine Inflation: Reloaded

自然度规-仿射暴胀:重装上阵

D. Kraiko, A. Racioppi

AI总结 本文重新研究了自然暴胀模型在度规仿射引力框架下的表现,考虑了暴胀场与Nieh-Yan项之间的周期性非最小耦合效应。研究发现,仅靠该耦合在强耦合极限下会导致线性暴胀预测,无法挽救自然暴胀模型,但若同时引入与里奇标量的类似非最小耦合,则能很好地符合观测数据。值得注意的是,该模型即使在亚普朗克尺度周期性和较小耦合常数下仍具有可行性。

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16 pages, 6 figures
AI中文摘要

我们在度规-仿射引力的框架下重新审视自然暴胀,考虑暴胀子与Nieh-Yan项之间的周期非最小耦合的影响。仅这一项在强耦合极限下会导致线性暴胀预言,无法拯救自然暴胀场景。然而,一旦加入与Ricci标量的类似非最小耦合,就能轻松实现与数据的一致性。值得注意的是,即使在亚普朗克周期尺度和相对较小(量级为1)的非最小耦合下,该场景仍然可行。

英文摘要

We revisit natural inflation within the framework of metric-affine gravity, considering the impact of a periodic non-minimal coupling between the inflaton and the Nieh-Yan term. Such a term, alone, leads to linear inflation predictions in the strong coupling limit and cannot help to rescue the natural inflation scenario. However, once an analogous non-minimal coupling with the Ricci scalar is added, agreement with data can be easily achieved. Remarkably, the scenario remains viable even with a sub-Planckian periodicity scale and relatively small (order of one) non-minimal couplings.

2605.23824 2026-05-25 hep-th quant-ph

The negativity core of a 1+1D massless scalar quantum field

1+1D无质量标量量子场的负性核心

Jason Pye, Atharva Hingane, Robert H. Jonsson

AI总结 本文研究了(1+1)维无质量实标量量子场中两个时空分离区域之间的真空纠缠特性。通过高斯态方法,作者解析计算了对数负度,并构建了承载该纠缠的局域模式的闭合解,称为“纠缠核心”。该成果深化了对量子场纠缠结构的理解,并为扩展到更高维及费米场提供了方向。

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6 pages, 2 figures
AI中文摘要

真空纠缠是量子场论的一个基本特征,展现出尚未完全理解的丰富结构。在这里,我们提供了(1+1)维自由无质量实标量场中两个有界类空分离区域之间纠缠的完整刻画。利用高斯态方法,我们解析计算了对数负性,并构造了携带它的局域模式(称为负性核心)的闭式解。这些结果加深了我们对量子场的理解,并提示了向更高维度和费米子场的推广。

英文摘要

Vacuum entanglement is a fundamental feature of quantum field theory exhibiting rich structure that is not completely understood. Here, we provide a complete characterization of the entanglement between two bounded spacelike-separated regions in a (1+1)-dimensional free massless real scalar field. Employing Gaussian state methods, we analytically compute the logarithmic negativity and construct closed-form solutions for the localized modes carrying it, called negativity cores. These results deepen our understanding of quantum fields and suggest extensions to higher dimensions and fermionic fields.

2605.23818 2026-05-25 astro-ph.HE

An extremely bright slow-rising afterglow from an off-axis jet in GRB 260310A

GRB 260310A 中离轴喷流产生的极亮缓升余辉

Yu-Han Yang, Roberto Ricci, Eleonora Troja, Muskan Yadav, Yi-Han Iris Yin, Rubén Sánchez-Ramírez, Brendan O'Connor, Niccoló Passaleva, Alberto J. Castro-Tirado, Hendrik van Eerten, Simone Dichiara, Vincenzo Galluzzi, Narjes Shahamat Dehsorkh, Iván Agudo, Jesús Aceituno, Malte Busmann, María D. Caballero-García, Emilio Fernández-García, Daniel Gruen, Maria Gritsevich, Sergiy Guziy, David Hiriart, You-Dong Hu, Martin Jelínek, Alexander Kutyrev, Alzbeta Malenakova, Filip Novotny, Ignacio Pérez-García, Shashi B. Pandey, Jorma Ryske, Alfredo Sota, Jan Strobl, Hira Waseem, Siyu Wu

AI总结 本文研究了近邻长伽马射线暴GRB 260310A,其红移约为0.153,伴随有宽线Ic型超新星。尽管其伽马射线爆发能量适中,但其在X射线、光学和射电波段的余辉异常明亮,且光学余辉表现出延迟起始和缓慢上升的特征。研究认为这一现象可由偏离轴向观测的喷流模型解释,并通过多波段观测验证了逆激波和正激波成分的存在,为偏离轴向几何中的余辉模型提供了首次测试。

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26 pages, 11 figures, 1 table; comments welcome
AI中文摘要

我们呈现了GRB 260310A的多波段研究,这是一个邻近的长时伽马射线暴,红移$z\simeq0.153$,与一颗宽谱Ic型超新星成协。尽管其瞬时伽马射线输出较弱,$E_{\gamma,\rm iso}\simeq3.5\times10^{50}$ erg,GRB 260310A在X射线、光学和射电波段展现出有史以来观测到的最亮余辉之一。其表观亮度并非唯一显著特征。光学余辉呈现延迟起始,表现为缓慢上升阶段,斜率$\alpha\approx-1$,以及约0.1天的晚峰值。我们认为,弱瞬时辐射、硬峰值能量和迟滞余辉起始的组合自然地被一个离轴观测的GRB喷流所解释。射电频谱能量分布与同步辐射一致,并指示存在反向激波和前向激波成分,从而首次在离轴几何中检验了反向激波模型。X射线余辉呈现显著的再增亮,监测时间长达约68天,且无谱演化证据。在$T_0+55$天时,15 GHz处测量到低水平线偏振,$\Pi\approx1.7\%$,表明在这些晚期,前向激波是从射电到X射线的主导发射成分。这一晚期再增亮对双成分喷流模型构成了关键检验。如果将其解释为更离轴观测的窄喷流核心的出现,则意味着对于正轴观测者而言,其亮度和能量将极为极端。

英文摘要

We present a multi-wavelength study of GRB 260310A, a nearby long-duration gamma-ray burst at $z\simeq0.153$ associated with a broad-lined Type Ic supernova. Despite its modest prompt gamma-ray output, $E_{γ,\rm iso}\simeq3.5\times10^{50}$ erg, GRB\,260310A exhibits one of the brightest afterglows ever observed in the X-ray, optical, and radio bands. Its apparent brightness is not its only remarkable feature. The optical afterglow displays a delayed onset, characterized by a slow rising phase, with slope $α\approx-1$, and a late peak at $\approx$0.1 d. We argue that the combination of weak prompt emission, hard peak energy, and late afterglow onset is naturally explained by a GRB jet viewed off-axis. The radio spectral energy distributions are consistent with synchrotron radiation and indicate the presence of both reverse- and forward-shock components, thus providing a first test of reverse-shock models in an off-axis geometry. The X-ray afterglow displays a prominent rebrightening, monitored for up to $\approx$68 d with no evidence of spectral evolution. A low level of linear polarization, $Π\approx1.7\%$, is measured at 15 GHz at $T_0+55$ d and suggests that, at these late times, the forward-shock is the dominant emission component from radio to X-rays. This late-time rebrightening represents a critical test for the two-component jet model. If interpreted as the emergence of a narrow jet core viewed further off-axis, it would imply extreme luminosities and energetics for an on-axis observer.