Upper bound on heat kernels of finite particle systems of Keller-Segel type
Keller-Segel型有限粒子系统热核的上界
AI总结 通过与非局部算子的联系,证明了Keller-Segel型有限粒子系统热核的上界,该系统表现出爆破效应。
Keller-Segel型有限粒子系统热核的上界
S.E.Boutiah, D.Kinzebulatov
AI总结 通过与非局部算子的联系,证明了Keller-Segel型有限粒子系统热核的上界,该系统表现出爆破效应。
我们获得了Keller-Segel型有限粒子系统热核的上界,该系统表现出爆破效应。证明利用了与某些非局部算子的联系。
We obtain upper bound on the heat kernel of Keller-Segel type finite particle system that exhibit blow up effects. The proof exploits a connection with certain non-local operators.
X型射电星系光学光谱中双峰窄发射线的起源
Ghosh Prajnadipt, Ravi Joshi, Xiaolong Yang, Yingkang Zhang, Gopal-Krishna, Paul J. Wiita, Dusmanta Patra, Ankit Patel, Arti Goyal, Gourab Giri, Santanu Mondal, Vibhore Negi, Marek Weżgowiec, Katarzyna Małek, Xue-Bing Wu, Luis C. Ho
AI总结 研究X型射电星系中双峰窄发射线的起源,发现约30%的XRG呈现[O III]双峰,远高于普通星系,且双峰成分主要由AGN驱动,暗示约95%的概率存在双AGN系统。
我们研究了X型射电星系(XRGs)作为双或二元超大质量黑洞(SMBHs)潜在宿主的光学双峰窄发射线(DPNELs)。利用SDSS和DESI巡天的可用光学光谱,我们在187个XRG样本中识别出55个DPNEL源。我们发现XRG中[O III] DPNEL的出现率约为30%,显著高于普通星系群体中观察到的约1%。通过光学(包括[O III]λ5007、Hα、Hβ、[N II]λ6584和[S II]λλ6716,6731)和中红外诊断图,我们发现两个成分主要都由AGN驱动,意味着存在双AGN系统的概率约为95%。相比之下,由恒星质量、颜色和红移匹配的非XRG DPNEL星系对照组显示较低的双AGN比例,该比例强烈依赖于射电光度,从射电未探测星系中的约25%上升到射电探测星系中的约54%,并在射电明亮的XRG和FR-II射电星系中达到约95%。有趣的是,超过30%的DPNEL XRGs拥有伴星系,支持这些系统的并合驱动起源。最后,我们利用VLBA在1.4、4.3和7.6 GHz的观测分析了7个XRG的秒差距尺度射电结构,仅在一个源中分辨出核心。尽管如此,平坦的射电谱指数、类似AGN的发射线性质以及5个案例中发现的射电-光学VLBA-Gaia位置偏移共同支持了XRG是强双/二元AGN候选体的解释。
We investigate X-shaped radio galaxies (XRGs) with optical double-peaked narrow emission lines (DPNELs) as potential hosts of dual or binary supermassive black holes (SMBHs). Using available optical spectra from the SDSS and DESI surveys, we identify 55 DPNEL sources among a sample of 187 XRGs. We find that the occurrence of [O III] DPNELs in XRGs is $\sim$30 %, which is substantially higher than the $\sim$1 % observed in the general galaxy population. Using optical (involving {[O III]$\lambda$5007}, H$\alpha$, H$\beta$, {[N II]$\lambda$,6584}, and {[S II]$\lambda\lambda$6716,6731}) and mid-infrared diagnostic diagrams, we found that both components are predominantly AGN-powered, implying a $\sim$95 % probability of hosting dual AGN systems. In comparison, a stellar-mass-, color-, and redshift-matched control sample of non-XRG DPNEL galaxies shows a lower dual AGN fraction, which depends strongly on radio luminosity, rising from ~25 % in radio-undetected to ~54 % in radio-detected galaxies, and reaching ~95 % in radio-bright XRGs and FR-II radio galaxies. Interestingly, more than 30 % of DPNEL XRGs have companion galaxies, supporting a merger-driven origin for these systems. Finally, we analyze parsec-scale radio structure in 7 XRGs using VLBA observations at 1.4, 4.3, and 7.6 GHz, resolving the core in only one source. Nevertheless, flat radio spectral indices, AGN-like emission-line properties, and radio-optical VLBA-Gaia positional offsets found in 5 cases together support the interpretation that XRGs are strong dual/binary AGN candidates.
手性活性粒子在涨落密度场中输运的解析理论
Jayam Joshi, Abhra Puitandy, Shradha Mishra
AI总结 针对三维手性活性布朗粒子在涨落密度场中的输运,建立了闭式解析理论,推导了均方位移和时变扩散率的精确表达式,揭示了手性与密度耦合对定向持久性和动力学交叉的影响。
我们发展了一个闭式解析理论,用于描述三维手性活性布朗粒子在涨落局域密度场中的输运,该密度场模拟了稠密活性介质中的位阻和动力学相互作用。密度场被建模为具有有限相关时间$\tau$和涨落强度$\sigma_\rho^2$的Ornstein-Uhlenbeck过程,同时捕捉空间涨落和时间记忆。在此框架内,我们推导了均方位移和时变扩散率的精确表达式,揭示了手性和密度耦合如何共同重整化定向持久性并产生非平凡的动力学交叉。该理论预测:(i) 起始于局域较密区域的粒子具有异常高的初始扩散率,这是由于局部泳动压力梯度驱动的瞬态活性漂移;(ii) 均匀化密度不均匀性的有限交叉时间$t_c$,动力学对初始局域密度环境的瞬态依赖性源于密度涨落的非平衡演化,当对平稳初始条件($\rho_0 = \rho_\infty$)取平均时,这种依赖性不会持续;(iii) 非单调的$t_c(\Omega)$,在中等手性处出现全局最小值,以及长时间扩散率$D_\infty(\Omega)$的三区域抑制,与模拟中观察到的微团簇相一致;(iv) 在最优手性$\Omega^*$处,均方位移的早期振荡强度出现共振峰,该最优手性由定向扩散、密度场去相关和施加旋转的共同作用决定。该框架捕捉了$D_\infty$对$Pe$和$\Omega$的定性依赖关系,其中$Pe$表示Péclet数,同时揭示了活性物质中依赖于手性的输运特征。
We develop a closed-form analytical theory for the transport of a chiral active Brownian particle in three dimensions, moving through a fluctuating local density field that models steric and dynamical interactions in a dense active medium. The density field is modeled as an Ornstein--Uhlenbeck process with finite correlation time $\tau$ and fluctuation strength $\sigma_\rho^2$, capturing both spatial fluctuations and temporal memory. Within this framework, we derive exact expressions for the mean-squared displacement and time-dependent diffusivity, revealing how chirality and density coupling jointly renormalise orientational persistence and generate nontrivial dynamical crossovers. The theory predicts: (i) anomalously high initial diffusivity for particles starting in locally denser regions, arising from a transient active drift driven by local swim-pressure gradients; (ii) a finite crossover time $t_c$ for homogenising density inhomogeneities, with a transient dependence of the dynamics on the initial local density environment which arises from the non-equilibrium evolution of density fluctuations and does not persist when averaging over stationary initial conditions ($\rho_0 = \rho_\infty$); (iii) a non-monotonic $t_c(\Omega)$ with a global minimum at intermediate chirality, and a three-regime suppression of long-time diffusivity $D_\infty(\Omega)$, consistent with micro-clustered phases observed in simulations; and (iv) a resonance-like peak in the early-time oscillatory strength of the mean-squared displacement at an optimal chirality $\Omega^*$, set by the interplay of orientational diffusion, density-field decorrelation, and imposed rotation. The framework captures the qualitative dependence of $D_\infty$ on $Pe$ and $\Omega$, {where Pe denotes the Péclet number}, while uncovering chirality-dependent transport features in active matter.
通过经典伊辛链对偶性实现二维环面码的高效简单吉布斯态制备
Pablo Páez-Velasco, Niclas Schilling, Samuel O. Scalet, Frank Verstraete, Ángela Capel
AI总结 提出多项式深度对偶变换概念,利用其将量子哈密顿量对偶到经典哈密顿量,从而构建高效吉布斯采样器,以二维环面码为例证明其对偶于两个解耦经典伊辛自旋链。
我们引入了多项式深度对偶变换的概念,该变换通过一个多项式深度的量子电路的共轭作用关联两组算子代数,并利用这一概念为多种有趣的量子哈密顿量构建高效的吉布斯采样器,因为这些哈密顿量是多项式深度对偶于经典哈密顿量的。例如,二维环面码就是这种情况,我们证明对于任意系统尺寸,它多项式深度对偶于两个解耦的经典伊辛自旋链,并给出证据表明这种对偶性适用于一大类稳定子哈密顿量。此外,我们将上述对偶性概念扩展到林德布拉德算子,以证明混合时间以及其他量如谱间隙或修正的对数索博列夫不等式在对偶下保持不变。
We introduce the notion of polynomial-depth duality transformations, which relates two sets of operator algebras through a conjugation by a poly-depth quantum circuit, and make use of this to construct efficient Gibbs samplers for a variety of interesting quantum Hamiltonians as they are poly-depth dual to classical Hamiltonians. This is for example the case for the 2D toric code, which is demonstrated to be poly-depth dual to two decoupled classical Ising spin chains for any system size, and we give evidence that such dualities hold for a wide class of stabilizer Hamiltonians. Additionally, we extend the above notion of duality to Lindbladians in order to show that mixing times and other quantities such as the spectral gap or the modified logarithmic Sobolev inequality are preserved under duality.
强关联绝缘体的电子-声子耦合朗之万动力学
Rico Pohle, Yukitoshi Motome, Terumasa Tadano, Shintaro Hoshino
AI总结 从第一性原理推导出自旋-轨道耦合莫特绝缘体的广义随机LLG方程,显式包含电子-声子耦合,通过路径积分形式自然处理耗散和热涨落,并数值验证了能量弛豫和热化行为。
Landau-Lifshitz-Gilbert (LLG) 方程被广泛用于研究莫特绝缘体中的自旋动力学。然而,由于能量阻尼通常是唯象引入的,它们描述非平衡过程的有效性以及与实际材料中耗散的微观起源的联系仍不清楚。在本文中,我们从第一性原理出发,为自旋-轨道耦合的莫特绝缘体推导了广义随机LLG方程,明确包含了电子自由度与晶格振动之间的耦合。我们的方法基于沿Keldysh轮廓构建的路径积分形式,通过声子浴和涌现的随机噪声相互作用,自然地解释了耗散和热涨落。我们通过数值积分与爱因斯坦声子耦合的双轨道自旋链的运动方程来验证理论框架。得到的能量弛豫模拟了真实的冷却动力学,在热化过程中表现出非平凡的瞬态行为,并在平衡时准确再现了热力学性质。我们进一步展示了电子-声子耦合如何导致激发谱中电子和声子模式的杂化,并表明传统LLG方程可作为我们微观理论的极限情况恢复。这些结果为在强关联系统中捕捉耗散自旋动力学(包括平衡和非平衡情况)建立了一个稳健可靠的框架。
The Landau-Lifshitz-Gilbert (LLG) equations are widely used to study spin dynamics in Mott insulators. However, because energy damping is typically introduced phenomenologically, their validity for describing nonequilibrium processes and their connection to the microscopic origin of dissipation in real materials remains unclear. In this paper, we derive generalized stochastic LLG equations from first principles for spin-orbital coupled Mott insulators, explicitly incorporating the coupling between electronic degrees of freedom and lattice vibrations. Our approach is based on a path-integral formalism formulated along the Keldysh contour, which naturally accounts for dissipation and thermal fluctuations through interactions with a phonon bath and emergent stochastic noise. We benchmark our theoretical framework by numerically integrating the equations of motion for a two-orbital spin chain coupled to Einstein phonons. The resulting energy relaxation mimics realistic cooling dynamics, exhibits nontrivial transient behavior during thermalization, and accurately reproduces thermodynamic properties upon equilibration. We further demonstrate how electron-phonon coupling induces hybridization between electronic and phononic modes in the excitation spectrum and show that the conventional LLG equations are recovered as a limiting case of our microscopic theory. These results establish a robust and reliable framework for capturing dissipative spin dynamics in strongly correlated systems, both in and out of equilibrium.
辛相干性:量子态中位置-动量相关性的度量
Varun Upreti, Ulysse Chabaud
AI总结 提出辛相干性作为位置-动量相关性的忠实且易计算的度量,证明其单调性和鲁棒性,并揭示其与几何量子失谐的对应关系及在固定能量下的最大相关性。
海森堡不确定性原理所强调的位置和动量的相互依赖性是量子物理的基石。然而,位置-动量相关性却很少受到系统性的关注。受玻色子量子物理学最新发展的推动,这些发展强调了它们在量子热力学、计量学和计算中的相关性,我们建立了一个通用框架来研究和量化量子态中的位置-动量相关性。我们引入了辛相干性,这是一个忠实且易于计算的度量,定义为编码位置-动量相关性的协方差矩阵块的Frobenius范数,并证明了辛相干性在相关操作下是单调的,并且在小的扰动下是鲁棒的。此外,利用Barthe等人(Phys. Rev. Lett. 134, 070604)最近的映射,该映射将玻色子态的协方差矩阵与有限维系统的密度矩阵联系起来,我们表明位置-动量相关性对应于虚拟有限维量子态中的超经典相关性,而辛相干性自然地映射到几何量子失谐。考虑能量约束,我们确定了在固定能量下可实现的最大位置-动量相关性,揭示了相应最优态的结构性见解。最后,我们通过量子信息任务和量子热力学中的几个例子说明了辛相干性的操作相关性。在此过程中,我们建立了关于矩阵范数和量子协方差矩阵的新技术结果,并展示了将协方差矩阵视为虚拟量子态的密度矩阵的概念意义。
The interdependence of position and momentum, as highlighted by the Heisenberg uncertainty principle, is a cornerstone of quantum physics. Yet, position-momentum correlations have received little systematic attention. Motivated by recent developments in bosonic quantum physics that underscore their relevance in quantum thermodynamics, metrology, and computing, we establish a general framework to study and quantify position-momentum correlations in quantum states. We introduce symplectic coherence, a faithful and easily computable measure defined as the Frobenius norm of the block of the covariance matrix encoding position-momentum correlations, and demonstrate that symplectic coherence is monotone under relevant operations and robust under small perturbations. Furthermore, using a recent mapping by Barthe et al. (Phys. Rev. Lett. 134, 070604) which relates the covariance matrix of a bosonic state to the density matrix of a finite-dimensional system, we show that position-momentum correlations correspond to beyond-classical correlations in a virtual finite-dimensional quantum state, with symplectic coherence mapping naturally to geometric quantum discord. Taking energy constraints into account, we determine the maximal position-momentum correlations achievable at fixed energy, revealing structural insights about the corresponding optimal states. Finally, we illustrate the operational relevance of symplectic coherence through several examples in quantum information tasks and quantum thermodynamics. In the process, we establish new technical results on matrix norms and quantum covariance matrices, and demonstrate the conceptual significance of viewing covariance matrices as density matrices of virtual quantum states.
因果序的贝尔类不等式的实验违背
Yu Guo, Hao Tang, Bo-Xuan Wang, Min-Yu Lv, Jia-Wen, Fan, Xiao-Min Hu, Yun-Feng Huang, Chuan-Feng Liu, Guang-Can Guo, Giulio Chiribella, Bi-Heng Liu
AI总结 通过四光子实验,在类空间隔条件下以5.7个标准差违背了因果序的贝尔类不等式,验证了量子力学中因果序的不确定性。
量子力学与物理过程以不确定顺序发生的情景兼容。理论上,这种特征可以通过对观测到的关联的不等式违背来检测,类似于贝尔不等式。然而,由于所需设置的复杂性,直到最近才出现此类违背的实验演示。本文报告了一个涉及四方关联的贝尔类不等式的实验违背,其中一方与其他方类空间隔。我们的演示采用3公里光纤卷模拟类空间隔,并在光子时间仓编码、纳秒同步和精确温度稳定方面实现了高速操作。这些实验进展实现了5.7个标准差的违背,并为在保证类空间隔的条件下认证不确定顺序开辟了道路,但该认证并非设备无关,因为它依赖于对设置的知识来排除双向信号传递——这是经典无环时空中实现固有的漏洞,可能在未来的量子时空测试中得到解决。
Quantum mechanics is compatible with scenarios where physical processes happen in an indefinite order. In theory, this feature could be detected through violations of inequalities on the observed correlations, analogous to Bell inequalities. However, experimental demonstrations of such violations have been missing until recently due to the complexity of the required setup. Here we report an experimental violation of a Bell-like inequality involving the correlations of four parties, one of which is spacelike separated from the others. Our demonstration employs 3 km fiber spools to simulate spacelike separation, and achieves high-speed operations in photonic time-bin encoding, nanosecond synchronization, and accurate temperature stabilization. These experimental advances enable a violation by 5.7 standard deviations and open a path towards a certification of indefinite order in conditions that guarantee spacelike separation with existing state-of-the-art devices. However, the certification is not device-independent, as it relies on knowledge about the setup to exclude bidirectional signaling--a loophole inherent to implementations in classical acyclic spacetimes, which may be resolved in future quantum-spacetime tests.
统一性与纹理普遍性:厄米性的本质
Pralay Chakraborty, Subhankar Roy
AI总结 基于Δ(27)群和循环对称性提出统一框架,用三个通用参数描述轻子和夸克质量矩阵,揭示下型夸克和轻中微子质量矩阵的厄米纹理,并探讨轻子味破坏、混合矩阵非幺正性及重整化群演化稳定性。
提出了一个基于$\Delta(27)$群并辅以其他循环对称性的统一框架,该框架涵盖了I型狄拉克跷跷板机制,保持了汤川耦合的自然性。它有助于用\textit{三个通用参数}:$\Sigma_1$、$\Sigma_2$和$\Sigma_3$来可视化轻子和夸克扇区内的质量矩阵,强调下型夸克和轻中微子质量矩阵表现出\textit{厄米}纹理。探讨了几个现象学方面,如轻子味破坏和轻子混合矩阵的非幺正性。还研究了所提出的纹理在重整化群演化下的稳定性。
A unified framework sheltering the type-I Dirac seesaw, based on the $\Delta(27)$ group supplemented by other cyclic symmetries is proposed, preserving the naturalness of Yukawa couplings. It helps to visualize mass matrices within the lepton and quark sectors in terms of \textit{three universal parameters}: $\Sigma_1$, $\Sigma_2$, and $\Sigma_3$, highlighting that the down-type quark and light neutrino mass matrices exhibit a \textit{Hermitian} texture. Several phenomenological aspects, such as lepton flavour violation and nonunitarity of the lepton mixing matrix are explored. The stability of the proposed texture under renormalization group evolution is also investigated.
$μ$LHC:基于反μ子环和HL-LHC的$μ^+p$对撞机
D. Akturk, A. C. Canbay, H. Dagistanli, B. Dagli, U. Kaya, B. Ketenoglu, A. Kilic, F. Kocak, A. Ozturk, S. Sultansoy, I. Tapan, F. Zimmermann
AI总结 提出基于HL-LHC的反μ子-质子对撞机概念设计,利用超冷μ子束技术实现5.3 TeV质心能量,亮度超10^{33} cm^{-2}s^{-1},覆盖小x和高Q²区域,用于QCD、希格斯物理及BSM研究。
提出了基于HL-LHC的反μ子-质子对撞机(${\mu}$LHC)的概念设计和性能评估。利用基于成熟J-PARC超冷${\mu}^{+}$束流技术的${\mu}$TRISTAN概念,${\mu}$LHC将有机会实现5.3 TeV的质心能量,显著超过EIC和LHeC。探索了两种用于${\mu}^{+}$加速的增强环方案:基于${\mu}$TRISTAN的系统以及重新利用的LHeC ERL系统。预测可实现的亮度超过$10^{33} cm^{-2}s^{-1}$。${\mu}$LHC提供了更宽的运动学平面覆盖,特别是在小x和高$Q^{2}$区域,对QCD基础和希格斯玻色子性质有重要贡献。其在BSM物理方面的独特潜力扩展到与μ子相关的现象,如激发μ子、色八重态μ子、轻夸克和接触相互作用。还概述了可能的探测器概念。鉴于超冷${\mu}^{+}$束流技术的成熟度,${\mu}$LHC比μ子对撞机更易于早期实现,使其成为高能物理未来的关键工具。
Conceptual design and performance evaluation of HL-LHC based antimuon-proton collider (${\mu}$LHC) are presented. Leveraging the ${\mu}$TRISTAN concept based on established J-PARC ultra-cold ${\mu}^{+}$ beam technology, ${\mu}$LHC will give the opportunity to achieve a 5.3 TeV center-of-mass energy, significantly surpassing EIC and LHeC. Two booster ring options for ${\mu}^{+}$ acceleration, namely, a ${\mu}$TRISTAN-based and a repurposed LHeC ERL-based systems, are explored. Achievable luminosities are predicted to exceed $10^{33} cm^{-2}s^{-1}$. The ${\mu}$LHC offers substantially wider kinematic plane coverage, particularly in small-x and high-$Q^{2}$ regions, significantly contributing to QCD basics and Higgs boson properties. Its unique potential for BSM physics extends to muon-related phenomena like excited muons, color-octet muons, leptoquarks, and contact interactions. A possible detector concept is also outlined. Given the maturity of ultra-cold ${\mu}^{+}$ beam technology, ${\mu}$LHC is highly feasible for earlier realization than the muon collider, positioning it as a critical tool for the future of high energy physics.
红移空间中的各向异性计数:从星系巡天获取宇宙学约束的新途径
Paweł Drozda, Wojciech A. Hellwing, Maciej Bilicki
AI总结 提出用椭球窗口替代传统球对称平滑核的体平均相关函数(VACF)框架,通过定义椭球VACF和累积量,利用N体模拟分析红移空间畸变效应,发现窗口形状随畸变状态变化,且红移空间偏斜度的形状依赖性对fσ8敏感,为星系巡天提供高效的信息丰富分析工具。
我们通过用各向异性的椭球窗口替代传统的球对称平滑核,引入了体平均相关函数(VACF)框架的一种新扩展。这种广义方法能够研究形状依赖的成团统计量,并捕捉大尺度结构中编码的方向信息,特别是在红移空间中,星系分布因本动速度而发生畸变。我们定义并计算了椭球VACF $\bar{\xi}_J (r_{\parallel}, r_{\perp})$ 和相应的约化累积量 $s_J (r_{\parallel}, r_{\perp})$,从而允许在任意统计阶J上同时对尺度和各向异性具有敏感性。利用覆盖不同宇宙学参数 $\Omega_M$ 和 $\sigma_8$ 网格的COLA N体模拟套件,我们分析了椭球VACF和累积量在真实空间和红移空间中的行为。我们发现,最大化成团信号的平滑核形状强烈依赖于红移空间畸变状态:在真实空间为球形,在手指上帝主导的畸变区域为长条形,在Kaiser挤压主导的区域为扁球形。虽然标准VACF振幅主要对 $\sigma_8$ 敏感,但红移空间偏斜度的形状依赖性对组合增长参数 $f \sigma_8$ 表现出连贯响应,相邻模型之间的典型灵敏度在1-3 $\sigma$ 水平。我们的结果表明,椭球VACF为计数-在-细胞分析提供了一种计算高效且信息丰富的推广,对星系巡天数据、暗晕目录以及超出 $\Lambda CDM$ 的引力宇宙学测试具有广阔的应用前景。
We introduce a novel extension of the volume-averaged correlation function (VACF) framework by replacing the traditional spherical smoothing kernels with anisotropic, ellipsoidal windows. This generalized approach enables the study of shape-dependent clustering statistics and captures directional information encoded in large-scale structure, particularly in redshift space where galaxy distribution is distorted by peculiar velocities. We define and compute ellipsoidal VACFs $\bar{\xi}_J (r_{\parallel}, r_{\perp})$ and the corresponding reduced cumulants $s_J (r_{\parallel}, r_{\perp})$, allowing for joint sensitivity to both scale and anisotropy across arbitrary statistical order J. Using a suite of COLA N-body simulations spanning a grid of cosmologies with varying $\Omega_M$ and $\sigma_8$, we analyze the behavior of ellipsoidal VACFs and cumulants in both real and redshift space. We find that the shape of the smoothing kernel that maximizes the clustering signal depends strongly on the redshift-space distortion regime: spherical in real space, prolate in the Fingers-of-God-dominated regime, and oblate in the Kaiser squashing-dominated regime. While the standard VACF amplitude is mainly sensitive to ${\sigma}_8$, the shape-dependence of redshift-space skewness shows a coherent response to the combined growth parameter $f \sigma_8$, with a typical sensitivity at the 1-3 $\sigma$ level between neighboring models. Our results demonstrate that ellipsoidal VACFs offer a computationally efficient and information-rich generalization of counts-in-cells analysis, with promising applications to galaxy survey data, halo catalogs, and cosmological tests of gravity beyond $\Lambda CDM$.
拓扑关联染色质结构域的中间态形成:基于量子退火的方法
Tobias Kempe, S. M. Ali Tabei, Mohammad H. Ansari
AI总结 利用量子退火模拟表观遗传伊辛模型,高效生成具有拓扑关联结构域特征的染色质构象,揭示一维表观遗传标记与三维折叠的关联机制。
拓扑关联染色质结构域是空间上分离的染色质区域,通过分隔活性和非活性基因组元件来调控转录。实验研究表明,它们的形成与表观遗传标记的局部模式相关,但将一维表观遗传景观与三维染色质折叠联系起来的精确机制仍不清楚。最近的模型将染色质表示为自旋系统,其中核小体被视为离散状态变量,其耦合强度源自基因组和表观遗传数据。由于高度阻挫和密集耦合,经典采样器难以处理这些模型。本文提出了一种量子退火方法,用于高效采样染色质状态,将表观遗传伊辛模型嵌入到D-Wave量子处理器的拓扑结构中。我们的方法不是重建精确的TAD大小分布或绝缘分数,而是再现统计特征,如平均标记发生率和核小体内/间相关性,同时生成表现出TAD样结构基序的构型。这些结果证明了量子退火作为探索染色质结构的一种替代方法,并为表观遗传建模提供了基础。
Topologically Associating Chromatin Domains are spatially distinct chromatin regions that regulate transcription by segregating active and inactive genomic elements. Empirical studies show that their formation correlates with local patterns of epigenetic markers, yet the precise mechanisms linking 1D epigenetic landscapes to 3D chromatin folding remain unclear. Recent models represent chromatin as a spin system, where nucleosomes are treated as discrete-state variables coupled by interaction strengths derived from genomic and epigenetic data. Classical samplers struggle with these models due to high frustration and dense couplings. Here, we present a quantum annealing (QA) approach to efficiently sample chromatin states, embedding an epigenetic Ising model into the topology of D-Wave quantum processors. Rather than reconstructing exact TAD size distributions or insulation scores, our method reproduces statistical features, such as mean marker incidences and intra-/inter-nucleosome correlations, while generating configurations that exhibit TAD-like structural motifs. These results demonstrate QA as an alternative to explore the chromatin architecture and provide a foundation in epigenetic modeling.
基于 $0-π$ 约瑟夫森结中分数涡旋的量子比特态
N. Stefanakis
AI总结 研究 $0-π$ 约瑟夫森结中分数涡旋与反涡旋导致的双稳态自由能景观,长结下为稳定平衡态,短结下量子隧穿增强,有望实现类量子比特二能级动力学。
我们研究了 $0-π$ 约瑟夫森结的静态性质及其作为超导量子比特的潜在应用。我们表明,分数涡旋和分数反涡旋构型产生了一个双稳态自由能景观,其稳定最小值对应于拓扑不同的分数涡旋态。在长结极限下,两种构型对应稳定的平衡态,而在短结极限下,降低的势垒表明量子隧穿和它们之间的杂化增强。这些结果表明,如果分数涡旋和分数反涡旋态之间存在有限的隧穿振幅,$0-π$ 约瑟夫森结可能为类量子比特的二能级动力学提供一个有物理意义的平台。
We investigate the static properties of $0-\pi$ Josephson junctions and their potential application as superconducting qubits. We show that fractional vortex and fractional antivortex configurations give rise to a bistable free-energy landscape with stable minima corresponding to topologically distinct fractional-vortex states. In the long-junction limit the two configurations correspond to stable equilibrium states, whereas in the short-junction limit the reduced barrier suggests enhanced quantum tunneling and hybridization between them. These results suggest that $0-\pi$ Josephson junctions may provide a physically meaningful platform for qubit-like two-level dynamics, provided that a finite tunneling amplitude exists between the fractional-vortex and fractional-antivortex states.
路径叠加激活可分离态的完美量子隐形传态能力
Sayan Mondal, Priya Ghosh, Ujjwal Sen
AI总结 本文证明,通过路径叠加,即使共享可分离态(包括纯乘积态),也能以1/4概率实现单位保真度的量子隐形传态,而因果序叠加则无此优势,并揭示控制量子比特的量子相干性是必要且充分的。
量子隐形传态是一种典型的量子通信协议,它借助共享纠缠和有限的经典通信,能够在两个远距离方之间传输任意量子态,而无需物理传输该态。我们证明,如果能够访问某种量子过程的叠加,则可以放宽量子隐形传态中的纠缠要求。文献中通常考虑两种量子过程的叠加:与量子映射识别的路径叠加和映射的不确定因果序叠加。我们发现,当协议中引入路径叠加时,即使双方共享某些类别的可分离态(包括纯乘积态),也能以1/4的非零概率实现单位保真度的量子隐形传态。相比之下,在隐形传态协议中辅助以量子映射的不确定因果序叠加,对于共享的纯乘积态并不能带来任何量子优势。此外,我们证明,在路径叠加辅助下,可分离Werner态也能在量子隐形传态中产生量子优势。最后,我们确定,控制量子比特中存在量子相干性是在路径叠加辅助的量子隐形传态中实现量子优势的充分必要条件。这些结果可能揭示了量子叠加在隐形传态与纠缠关系中的另一个普遍作用。
Quantum teleportation is a quintessential quantum communication protocol that enables the transmission of an arbitrary quantum state between two distant parties without physically transmitting the state with the help of shared entanglement and limited classical communication. We show that it is possible to relax the entanglement requirement in quantum teleportation if we have access to a certain strain of superposition of quantum processes. Two types of superposition of quantum processes are generally considered in the literature: superposition of paths identified with quantum maps and superposition of indefinite causal orders of the maps. We find that when superposition of paths is incorporated in the protocol, quantum teleportation with unit fidelity becomes possible with nonzero probability of 1/4 even when the two parties share certain classes of separable states, including pure product states. In contrast, the assistance of superposition of indefinite causal order of quantum maps in teleportation protocol does not enable any quantum advantage for shared pure product states. Furthermore, we show that separable Werner states can also yield quantum advantage in quantum teleportation assisted by the superposition of paths. Finally, we establish that the presence of quantum coherence in the control qubit is both necessary and sufficient to achieve quantum advantage in quantum teleportation assisted with superposition of paths. The results potentially uncover yet another role of quantum superposition, in general, in teleportation versus entanglement.
改进的δ-kick冷却:多次非理想脉冲
Harshil Neeraj, David C. Spierings, Joseph McGowan IV, Nicholas Mantella, Aephraim M. Steinberg
AI总结 提出使用高斯势的复合物质波透镜系统进行δ-kick冷却,通过组合吸引和排斥脉冲模拟谐波势,将动能温度降低2.5倍(2脉冲)或3.2倍(3脉冲)。
δ-kick冷却是一种通过减小动量宽度(以增加位置宽度为代价)来实现低动能温度的技术。在理想实现中,该方法使用谐波势提供单个近乎瞬时的动量脉冲。在实践中,通常使用在其中心附近近似谐波的势。因此,远离中心处谐波近似的失效限制了冷却性能。受光学中像差消除的启发,我们提出使用复合物质波透镜系统进行高斯势的δ-kick冷却。通过策略性地组合吸引和排斥脉冲,我们展示了模拟谐波势效应的可能性。对于具有合理实验参数的测试案例,我们的方法表明,使用2脉冲序列可将动能温度降低2.5倍,使用3脉冲序列可降低3.2倍。
Delta-kick cooling is a technique employed to achieve low kinetic temperatures by decreasing momentum width at the cost of increased position width. In an ideal implementation, this method uses a harmonic potential to deliver a single near-instantaneous momentum kick. In practice, potentials that are approximately harmonic near their center are commonly used. As a result, the breakdown of the harmonic approximation far from the center limits the cooling performance. Inspired by aberration cancellation in optics, we propose to use compound matter-wave lens systems for $\delta-$kick cooling with Gaussian potentials. By strategically combining attractive and repulsive kicks, we show that it is possible to mimic the effect of a harmonic potential. For a test case with reasonable experimental parameters, our method suggests a reduction in kinetic temperature by a factor of $2.5$ using a 2-pulse sequence and by a factor of $3.2$ using a 3-pulse sequence.
受限空间中活性和活性细丝的最优转运
Marin Vatin, Rosa Sinaasappel, Renske Kamping, Chantal Valeriani, Emanuele Locatelli, Antoine Deblais
AI总结 通过蠕虫模型和活性细丝模拟,发现活性与重定向共同控制受限空间中的逃逸,且中间温度下转运效率最高。
活性细丝通过受限空间的转运是许多过程的核心,从纳米孔中的DNA输运到细胞迁移中的细胞骨架动力学。这里,我们使用活的丝状正颤蚓作为模型系统,研究活性和细丝构象如何控制受限空间中的输运。通过温度调节活性,并在由窄桥连接的双室几何结构中追踪蠕虫动力学,我们量化了它们的转运行为和构象状态。与被动聚合物和细丝相比,我们发现轮廓长度对捕获动力学影响可忽略,而活性和重定向共同控制逃逸。引人注目的是,转运效率在中间温度(20°C)下最大化,此时定向推进和旋转扩散之间的平衡优化了探索。我们表明,捕获时间由构象重排的时间尺度与构象熵之间的相互作用控制,量化了可达到形状的多样性。切向驱动活性细丝的模拟定量再现了实验观察,并提供了一个最小物理框架来合理化最优活性的存在。更广泛地说,我们的结果确定了控制受限空间中活性细丝输运的一般原理,对生物系统和合成活性细长物体的设计都有意义。
Active filament translocation through confined spaces is central to processes ranging from DNA transport through nanopores to cytoskeletal dynamics in cell migration. Here, we use living filamentous \textit{Tubifex tubifex} worms as a model system to investigate how activity and filament conformation govern transport in confinement. By tuning activity via temperature and tracking worm dynamics in a two-chamber geometry connected by a narrow bridge, we quantify their translocation behavior and conformational states. In contrast to passive polymers and filaments, we find that contour length has negligible influence on trapping dynamics, while activity and reorientation jointly control escape. Strikingly, translocation efficiency is maximized at an intermediate temperature ($20^\circ$C), where a balance between directed propulsion and rotational diffusion optimizes exploration. We show that trapping times are governed by the interplay between the timescale of conformational rearrangements and the conformational entropy, quantifying the diversity of accessible shapes. Simulations of tangentially driven active filaments quantitatively reproduce the experimental observations and provide a minimal physical framework to rationalize the existence of an optimal activity. More broadly, our results identify general principles governing active filament transport in confinement, with implications for both biological systems and the design of synthetic active slender objects.
腔介导相互作用量子气体中准粒子激发的同步化
Gabriele Natale, Alexander Baumgärtner, Justyna Stefaniak, David Baur, Simon Hertlein, Dalila Rivero, Tilman Esslinger, Tobias Donner
AI总结 研究BEC-腔耦合系统中的耗散诱导准粒子同步化,通过腔辅助布拉格光谱观测到两个旋子模在异常点合并,揭示耗散驱动集体动力学并预示动态相变前兆。
驱动-耗散量子系统可以经历从稳态到动态相的转变,反映了集体非平衡行为的出现。我们研究了耦合到光学腔的玻色-爱因斯坦凝聚体中的这种转变,并开发了一种腔辅助布拉格光谱技术来解析其集体模式。我们观察到准粒子层面的耗散诱导同步化,其中两个旋子模在异常点合并。这揭示了耗散如何在微观上驱动集体动力学,并标志着动态相变的前兆。
Driven-dissipative quantum systems can undergo transitions from stationary to dynamical phases, reflecting the emergence of collective non-equilibrium behavior. We study such a transition in a Bose-Einstein condensate coupled to an optical cavity and develop a cavity-assisted Bragg spectroscopy technique to resolve its collective modes. We observe dissipation-induced synchronization at the quasiparticle level, where two roton-like modes coalesce at an exceptional point. This reveals how dissipation microscopically drives collective dynamics and signals a precursor to a dynamical phase transition.
耦合BEC-腔系统的能带结构:耗散和几何效应
David Baur, Simon Hertlein, Alexander Baumgärtner, Justyna Stefaniak, Tilman Esslinger, Gabriele Natale, Tobias Donner
AI总结 提出横向驱动BEC与光学腔耦合的理论模型,基于能带理论和平均场描述分析激发模性质,发现非厄米现象如交叉前驱模合并和奇异点,并解释泵浦与腔夹角偏离90°的作用。
我们提出了一个横向驱动的玻色-爱因斯坦凝聚体与光学腔耦合的理论模型。我们关注不同相干耦合之间的相互作用,这可以触发结构相变,即超辐射相变。我们的方法基于能带理论和平均场描述,能够全面分析系统激发模的性质,预示相变。通过纳入这些系统固有的耗散耦合,我们发现了非厄米现象,例如交叉前驱模的合并和奇异点(EPs)的出现。我们模型的一般公式允许我们解释横向泵浦与腔之间偏离$90^\circ$的夹角的作用。这为我们提供了对此类系统各种不同实现的统一视角。
We present a theoretical model for a transversally driven Bose-Einstein condensate coupled to an optical cavity. We focus on the interplay between different coherent couplings, which can trigger a structural phase transition, known as the superradiant phase transition. Our approach, based on band structure theory and a mean-field description, enables a comprehensive analysis of the nature of the system's excited modes, precursing the phase transitions. By incorporating dissipative couplings, intrinsic to these systems, we find non-Hermitian phenomena such as the coalescence of crossing precursor modes and the emergence of exceptional points (EPs). The general formulation of our model allows us to explain the role of an angle between transverse pump and the cavity deviating from $90^\circ$. This offers us a unified perspective on the plethora of different implementations of such systems.
Cayley第一超行列式是一种纠缠度量
Isaac Dobes, Naihuan Jing
AI总结 本文证明Cayley第一超行列式的绝对值幂次在可分态上为零,是LU不变量且在LOCC下平均不增,从而确立其为物理上有意义的纠缠度量,适用于2n-qudit态。
先前研究表明,2n量子比特纯态上的concurrence和n-tangle可以用Cayley第一超行列式表示,记为$\mathrm{hdet}$,表明它捕捉了态的部分2n路纠缠。本文严格证明,在纯态和混合态上,$|\mathrm{hdet}|^{2/d}$在可分态上恒为零,是LU不变量,且在LOCC下平均不增,从而证明$|\mathrm{hdet}|^{d/2}$是物理上有意义且合法的纠缠度量。此外,我们讨论几个关键例子来说明Cayley第一超行列式检测的特定纠缠类型:跨所有2n方的真正全d级GHZ型纠缠。综上,这确立了Cayley第一超行列式(确切地说是$|\mathrm{hdet}|^{2/d}$)作为concurrence和n-tangle到2n-qudit态的真正、有物理意义的推广。
Previously, it was shown that both the concurrence and $n$-tangle on $2n$-qubit pure quantum states can be expressed in terms of Cayley's first hyperdeterminant \cite{dobes2024qubits}, indicating that Cayley's first hyperdeterminant, denoted $\mathrm{hdet}$, captures some aspects of a state's $2n$-way entanglement. In this paper, we rigorously prove that on both pure and mixed states, $|\mathrm{hdet}|^{2/d}$ is identically zero on separable states, is an LU invariant, and is non-increasing on average under LOCC, thus demonstrating that $|\mathrm{hdet}|^{d/2}$ is a physically meaningful and legitimate entanglement measure. Moreover, we discuss a few key examples to illustrate the particular type of entanglement Cayley's first hyperdeterminant is detecting: genuine full $d$-level GHZ-type entanglement across all $2n$ parties. Combined, this establishes Cayley's first hyperdeterminant (or $|\mathrm{hdet}|^{2/d}$ to be precise), as a physically significant generalization of the $G$-concurrence and the $n$-tangle to $2n$-qudit states.
偏度作为引力的探针:真实空间与红移空间中的计数-单元
Paweł Drozda, Wojciech A. Hellwing, Maciej Bilicki
AI总结 利用N体模拟研究暗物质、晕和星系在真实与红移空间中的计数-单元偏度,比较GR与两种扩展引力模型,发现红移空间畸变抑制偏度但F5模型仍保持约4%偏差,且比值近似与引力模型无关,为星系巡天测试引力提供新工具。
我们利用ELEPHANT(扩展透镜物理与解析射线追踪)N体模拟套件,研究了暗物质、晕和星系分布在真实空间和红移空间中的计数-单元约化偏度$s_3$。我们比较了广义相对论(GR)与两种扩展引力(EG)模型:具有变色龙屏蔽的$f(R)$引力和具有Vainshtein屏蔽的正常分支Dvali-Gabadadze-Porrati(nDGP)模型。我们量化了红移空间畸变(RSD)对$s_3$的抑制,发现虽然小尺度偏度被强烈降低,但$F5$模型在星系样本中仍保持与GR约$4\\%$的偏差,对应$2\sigma$显著性。我们表明,比值$s_3^{\mathrm{RSD}}/s_3^{\mathrm{real}}$在不同示踪物和红移下近似与引力模型无关。我们的结果表明,真实空间预测可以帮助可靠地推断GR和扩展引力中的红移空间偏度,为利用当前和未来的星系红移巡天测试引力提供了新工具。
We study the counts-in-cells reduced skewness $s_3$ for dark matter, halo, and galaxy distributions in both real and redshift space, using the ELEPHANT ($\textit{Extended LEnsing PHysics with ANalytical ray Tracing}$) suite of $N$-body simulations. We compare General Relativity (GR) with two extended (EG) gravity models: $f(R)$ gravity with chameleon screening and the normal-branch Dvali-Gabadadze-Porrati (nDGP) model with Vainshtein screening. We quantify the suppression of $s_3$ by redshift-space distortions (RSD), finding that while small-scale skewness is strongly reduced, the $F5$ model retains a $\sim 4\%$ deviation from GR in galaxy samples, corresponding to a $2\sigma$ significance. We show that the ratio $s_3^{\mathrm{RSD}}/s_3^{\mathrm{real}}$ is approximately independent of the gravity model across tracers and redshifts. Our results demonstrate that real-space predictions can help reliably infer redshift-space skewness in both GR and extended gravity, providing a new tool for testing gravity with current and forthcoming galaxy redshift surveys.
多体晶格和的 Epstein zeta 方法
Andreas A. Buchheit, Jonathan K. Busse
AI总结 提出用 Epstein zeta 函数的奇异积分表示多体晶格和,将三维 ATM 三体晶格和计算时间从数周降至数分钟,且计算成本随 n 线性增长。
多体相互作用自然地出现在经典和量子多体系统的微扰处理中,并在凝聚态系统的描述中起着关键作用。在三体相互作用的情况下,Axilrod-Teller-Muto (ATM) 势对于材料性质的定量预测高度相关。本文解决了在 $d$ 维晶格系统中计算所得能量的数值计算这一长期存在的问题。我们提出了多体晶格和的一种高效可计算表示,即用 Epstein zeta 函数乘积的奇异积分表示。对于三维中的三体相互作用,该方法将计算 ATM 晶格和的运行时间从数周减少到数分钟。我们的方法进一步推广到一大类 $n$ 体晶格和。我们证明,该方法的计算成本仅随 $n$ 线性增加,避免了直接求和复杂度的指数增长。我们讨论了计算所出现的奇异积分的数值技术,并将我们的结果与可计算的特殊情况以及低维直接求和进行精度比较,对于大于系统维度的指数实现了完全精度。最后,我们应用该方法研究在有限压力下包含 ATM 三体项的 Lennard-Jones 二体相互作用的三维晶格系统的稳定性,发现随着 ATM 耦合强度的增加,晶格结构从面心立方转变为体心立方。这项工作为正在进行的关于多体相互作用对物质稳定性影响的研究奠定了数值和分析基础。
Many-body interactions arise naturally in the perturbative treatment of classical and quantum many-body systems and play a crucial role in the description of condensed matter systems. In the case of three-body interactions, the Axilrod-Teller-Muto (ATM) potential is highly relevant for the quantitative prediction of material properties. This work solves the long-standing issue of the numerical computation of the resulting energies in $d$-dimensional lattice systems. We present an efficiently computable representation of many-body lattice sums in terms of singular integrals over products of Epstein zeta functions. For three-body interactions in three dimensions, this approach reduces the runtime for computing the ATM lattice sum from weeks to minutes. Our approach further extends to a broad class of $n$-body lattice sums. We demonstrate that the computational cost of our method only increases linearly with $n$, evading the exponential increase in complexity of direct summation. We discuss techniques for numerically computing the arising singular integrals and compare the accuracy of our results against computable special cases and against direct summation in low dimensions, achieving full precision for exponents greater than the system dimension. Finally, we apply our method to study the stability of a three-dimensional lattice system with Lennard-Jones two-body interactions under the inclusion of an ATM three-body term at finite pressure, finding a transition from the face-centered-cubic to the body-centered-cubic lattice structure with increasing ATM coupling strength. This work establishes both the numerical and analytical foundation for an ongoing investigation into the influence of many-body interactions on the stability of matter.
边缘扭转莫尔超晶格中的晶格弛豫理论
Christophe De Beule, Gayani N. Pallewela, Mohammed M. Al Ezzi, Liangtao Peng, E. J. Mele, Shaffique Adam
AI总结 针对极小扭转角下莫尔材料中晶格弛豫的强耦合行为,提出解析理论,成功描述三角和蜂窝孤子网络,揭示普适标度律。
原子级薄层莫尔材料表现为弹性膜,在非常小的扭转角下,范德华粘附能远超过应变能。在这种“边缘扭转”区域,低粘附能区域扩展,覆盖大部分莫尔原胞,而所有不利的能量构型收缩形成由畴壁周期性网络连接的拓扑缺陷。我们找到了解析表达式,成功捕捉了三角孤子网络和蜂窝孤子网络的强耦合行为,与LAMMPS分子动力学模拟和连续弹性理论数值解的结果一致。存在一个涌现的普适性,理论由单个依赖于扭转角的参数表征。我们的公式对于理解当前广泛关注的材料(包括扭转双层石墨烯、平行和反平行堆叠的tWSe2和tMoTe2,以及任何具有相同堆叠对称性的其他扭转同质双层)的实验至关重要。
Atomically thin moiré materials behave like elastic membranes where at very small twist angles, the van der Waals adhesion energy much exceeds the strain energy. In this ``marginal twist" regime, regions with low adhesion energy expand, covering most of the moiré unit cell, while all the unfavorable energy configurations shrink to form topological defects linked by a periodic network of domain walls. We find analytical expressions that successfully capture this strong-coupling regime for both the triangular soliton network and the honeycomb soliton network matching predictions from LAMMPS molecular dynamics simulations, and numerical solutions of continuum elasticity theory. There is an emergent universality where the theory is characterized by a single twist-angle dependent parameter. Our formalism is essential to understand experiments on a wide-range of materials of current interest including twisted bilayer graphene, both parallel and antiparallel stacked tWSe2 and tMoTe2, and any other twisted homobilayer with the same stacking symmetry.
德西特宇宙中的曲速驱动
Remo Garattini, Kirill Zatrimaylov
AI总结 将曲速泡嵌入德西特宇宙背景,通过选择特定径向速度,实现非负能量密度并满足弱能量条件,探讨对暗能量模型和物理系统的应用。
推广H. Ellis将曲速泡嵌入黑洞背景的结果,我们将曲速泡引入德西特宇宙。我们证明,在特定条件下(即气泡以等于宇宙膨胀速度的径向速度运动),气泡可以具有严格非负的能量密度,弱能量条件和零能量条件在平均为零的总散度项下得到满足。我们讨论了这一结果的意义及其在暗能量模型(如“暗流体”和精质)以及物理系统(如卡西米尔腔和类比引力装置)中的可能应用。
Generalizing the result of H. Ellis who embedded a warp bubble in the background of a black hole, we introduce a warp bubble in a de Sitter universe. We show that under certain conditions (namely, that the bubble is moving in the radial direction at a velocity equal to the speed of the expansion of the universe), it is possible for the bubble to have strictly non--negative energy density, with the weak and null energy satisfied up to a total divergence term that averages to zero. We discuss the implications of this result and its possible applications to models of dark energy like "dark fluid" and quintessence, as well as to physical systems like Casimir cavities and analogue gravity setups.
基于pCCD方法计算轨道能量和成对轨道能量的简单高效计算策略
Seyedehdelaram Jahani, Somayeh Ahmadkhani, Katharina Boguslawski, Paweł Tecmer
AI总结 提出基于pCCD及其轨道优化变体的廉价计算策略,通过Koopmans定理计算轨道和成对轨道能量,近似电离势、电子亲和能及电荷间隙,在有机受体分子中实现低计算成本下的可靠预测。
我们引入了用于计算原子和分子系统中轨道和成对轨道能量的廉价计算策略。我们的方法基于对耦合簇双激发(pCCD) ansatz及其轨道优化变体。然后,计算出的轨道和成对轨道能量被用于近似电离势(IPs)、电子亲和能(EAs)、由此产生的电荷间隙、双电离势(DIPs)和双电子亲和能(DEAs)。我们的方法建立在标准Koopmans定理的基础上,并针对基于pCCD的波函数进行了改进。此外,我们利用规范Hartree-Fock或自然pCCD优化轨道将pCCD电子相关效应纳入模型。后者是(D)IP/D(EA)运动方程pCCD模型的对角近似。我们在不同基组大小的选定原子和一组24个有机受体分子上,针对理论和可用的实验数据对我们的新模型进行了基准测试。我们的数值结果表明,基于pCCD自然轨道的Koopmans方法提供了占据和虚轨道能量的平衡处理,从而以低计算成本实现了电荷间隙的可靠预测。
We introduce affordable computational strategies for calculating orbital and pair-orbital energies in atomic and molecular systems. Our methods are based on the pair Coupled Cluster Doubles (pCCD) ansatz and its orbital-optimized variant. The computed orbital and pair-orbital energies are then subsequently used to approximate ionization potentials (IPs), electron affinities (EAs), the resulting charge gaps, double ionization potentials (DIPs), and double electron affinities (DEAs). Our methodology builds on the standard Koopmans' theorem and refines it for a pCCD-based wave function. Furthermore, we incorporate pCCD electron correlation effects into the model utilizing canonical Hartree-Fock or natural pCCD-optimized orbitals. The latter represents a diagonal approximation to the (D)IP/D(EA) equation of motion pCCD models. We benchmarked our newly developed models against theoretical and available experimental data for selected atoms in various basis set sizes and a set of 24 organic acceptor molecules. Our numerical results show that the Koopmans' approach based on pCCD natural orbitals provides a balanced treatment of occupied and virtual orbital energies, resulting in reliable predictions of charge gaps at a low computational cost.
Epstein zeta函数的计算与性质及其在量子系统中的应用
Andreas A. Buchheit, Jonathan Busse, Ruben Gutendorf
AI总结 提出超指数收敛算法计算任意维度和参数的Epstein zeta函数,首次建立其全参数联合全纯延拓并刻画奇异性结构,实现高精度数值实现并应用于量子色散关系和Casimir能量计算。
Epstein zeta函数将经典的Riemann zeta函数推广到高维振荡晶格和,并最近成为模拟长程相互作用经典和量子多体系统的关键工具。因此,其计算和分析性质具有重要意义,但缺乏严格而全面的处理。我们通过引入一个带有误差界的超指数收敛算法来填补这一空白,该算法可计算任意维度和任意实参数的Epstein zeta函数。我们的方法伴随着对Epstein zeta函数分析性质的详细分析。我们首先给出其亚纯延拓、函数方程和对称性的简洁重述。然后,我们首次建立了其在所有参数中的联合全纯延拓,并完整刻画了由此产生的复杂奇异性结构,该结构控制着基于该函数的数值算法的收敛速度。认识到该函数可以分解为幂律奇异性和正则化解析部分,我们提供了一种无需抵消误差即可去除奇异性的算法。这有助于积分评估,并通过插值方法实现快速预计算。我们在EpsteinLib中首次实现了针对任意实参数的高性能实现,该库是一个带有Python和Julia绑定的C库,并严格基准测试了其性能和准确性,在维度1、2、3、4、6和8中实现了与已知解析结果的全精度评估,并在整个参数范围内与任意精度实现进行了对比。最后,我们将我们的方法应用于自旋系统中的量子色散关系和三维几何中的Casimir能量的计算。
The Epstein zeta function generalises the classical Riemann zeta function to oscillatory lattice sums in higher dimensions and has recently emerged as a key tool in the simulation of long-range interacting classical and quantum many-body systems. Its computation and analytic properties are therefore of significant interest, yet a rigorous and comprehensive treatment has been lacking. We address this gap by introducing a superexponentially convergent algorithm, complete with error bounds, for computing the Epstein zeta function in any dimension with arbitrary real parameters. Our approach is accompanied by a detailed analysis of the analytic properties of the Epstein zeta function. We first present a concise reformulation of its meromorphic continuation, functional equation, and symmetries. We then establish, for the first time, its joint holomorphic continuation in all parameters and offer a complete characterization of the resulting complex singularity structure, which governs convergence rates in numerical algorithms based on the function. Recognizing that the function can be decomposed into power-law singularities and a regularised analytic part, we provide an algorithm for removing singularities without cancellation error. This facilitates the evaluation of integrals and enables fast precomputations through interpolation methods. We present the first high-performance implementation for arbitrary real arguments in EpsteinLib, a C library with Python and Julia bindings, and rigorously benchmark its performance and accuracy, achieving full-precision evaluation against known analytic results in dimensions 1,2,3,4,6, and 8 and against an arbitrary precision implementation across the entire parameter range. Finally, we apply our methods to the computation of quantum dispersion relations in spin systems and Casimir energies in three-dimensional geometries.
弦振幅的$i\varepsilon$规则与正则化模积分
Jan Manschot, Zhi-Zhen Wang
AI总结 本文通过弦理论中的$i\varepsilon$规则,利用广义指数积分正则化方法,解析计算了开闭弦的单圈振幅,并证明了与Eberhardt-Mizera轮廓方法的一致性。
我们研究了弦理论单圈振幅中出现的积分,特别是基于量子场论$i\varepsilon$规则的弦理论类比解析延拓。对于开弦和闭弦的各种零点和两点单圈振幅,我们证明这种解析延拓等价于使用广义指数积分的正则化。我们的方法提供了每个质量水平简并度的精确表达式。对于有边界的单圈振幅,我们的结果形式为三个不同温度下配分函数的线性组合,依赖于变量$T_0$,但它们的和与该变量无关。振幅的虚部可以以闭合形式读出,而实部适合数值计算。尽管表达式相当不同,我们证明了我们的方法与Eberhardt-Mizera(2023)遵循Hardy-Ramanujan-Rademacher圆法提出的轮廓一致,并比较了这两种方法。我们包括对真空振幅的Ramond-Ramond扇区和Type I超弦理论两点振幅的应用。
We study integrals appearing in one-loop amplitudes in string theory, and in particular their analytic continuation based on a string theoretic analog of the $i\varepsilon$-prescription of quantum field theory. For various zero- and two-point one-loop amplitudes of both open and closed strings, we prove that this analytic continuation is equivalent to a regularization using generalized exponential integrals. Our approach provides exact expressions in terms of the degeneracies at each mass level. For one-loop amplitudes with boundaries, our result takes the form of a linear combination of three partition functions at different temperatures depending on a variable $T_0$, yet their sum is independent of this variable. The imaginary part of the amplitudes can be read off in closed form, while the real part is amenable to numerical evaluation. While the expressions are rather different, we demonstrate agreement of our approach with the contour put forward by Eberhardt-Mizera (2023) following the Hardy-Ramanujan-Rademacher circle method, and compare these two approaches. We include applications to the Ramond-Ramond sector of the vacuum amplitude and two-point amplitudes of Type I superstring theory.
非平坦埃克曼边界层:地形抬升、广义埃克曼抽吸和各向异性渐近行为
Yifei Jia, Yi Du, Lihui Guo
AI总结 研究快速旋转粘性流体在O(1)振幅非平坦边界上的奇异极限行为,通过多尺度渐近分析揭示地形通过宏观强迫和微观各向异性抽吸两种机制调节耗散,导出基于地形度量张量的广义速度场,并证明变厚度近似解的L^2收敛性。
埃克曼边界层是地球物理流体力学中的一个基本概念,描述了受旋转影响的近边界流体运动。在快速旋转和消失粘性的奇异极限框架内,埃克曼理论的经典研究(例如,Desjardins and Grenier (1999), Masmoudi (2000))主要局限于平坦或小振幅边界假设。传统的平坦边界假设掩盖了地形曲率引起的复杂机制;此外,即使小振幅扰动也将地形效应简化为简单的线性强迫项。因此,本文研究了在非平坦边界$z=B(x,y)$(振幅为$\mathcal{O}(1)$,斜率和曲率一致有界)上旋转流体的奇异极限行为。我们阐明了这种地形如何通过两种不同机制调节流体耗散:宏观地形强迫和微观各向异性抽吸。首先,利用多尺度渐近分析,我们构造了一类显式依赖于边界几何特征的近似解,得到了一个与经典模型根本不同的二维极限系统。该系统的一个关键创新是通过地形度量张量定义了一个广义速度场。这一公式不仅将传统的各向同性线性阻尼推广为各向异性几何阻尼,还将旋转效应耦合到宏观垂直加速度中。此外,利用能量方法,我们建立了这些变厚度近似解到原始三维系统弱解的$L^2$收敛性。最后,我们使用一类代表性的边界几何分析了控制大振幅地形上旋转流体运动的多重机制。
The Ekman boundary layer, a fundamental concept in geophysical fluid mechanics, describes the near-boundary fluid motion subject to rotation. Within the singular limit framework of rapid rotation and vanishing viscosity, classical studies of Ekman theory (e.g., Desjardins and Grenier (1999), Masmoudi (2000)) are predominantly restricted to flat or small-amplitude boundary assumptions. The conventional flat-boundary assumption obscures the complex mechanisms induced by topographic curvature; moreover, even small-amplitude perturbations reduce topographic effects to simple linear forcing terms. Consequently, this paper investigates the singular limit behavior of rotating fluids over a non-flat boundary $z=B(x,y)$ of $\mathcal{O}(1)$ amplitude with uniformly bounded slope and curvature. We elucidate how such topography modulates fluid dissipation through two distinct mechanisms: macroscopic topographic forcing and microscopic anisotropic pumping. First, using multi-scale asymptotic analysis, we construct a class of approximate solutions that explicitly depend on the boundary's geometric characteristics, yielding a two-dimensional limit system fundamentally distinct from classical models. A key innovation of this system is the introduction of a generalized velocity field defined via the topographic metric tensor. This formulation not only generalizes the traditional isotropic linear damping to anisotropic geometric damping but also couples rotational effects to macroscopic vertical acceleration. Furthermore, using energy methods, we establish the $L^2$ convergence of these variable-thickness approximate solutions to the weak solutions of the original three-dimensional system. Finally, we analyze the multiple mechanisms governing rotating fluid motion over large-amplitude topography using a representative class of boundary geometries.
洛伦兹几何中分裂定理的椭圆证明
Mathias Braun, Nicola Gigli, Robert J. McCann, Argam Ohanyan, Clemens Sämann
AI总结 通过引入负齐次椭圆p-d'Alembert算子,将洛伦兹分裂定理纳入黎曼几何的Cheeger-Gromoll分裂定理框架,给出新的简洁证明。
我们提供了洛伦兹几何中分裂定理的新证明,通过牺牲d'Alembert算子的线性性来恢复椭圆性,从而获得简洁性。为此,我们利用了一个负齐次(非一致)椭圆$p$-d'Alembert算子。这使得我们能够将Eschenburg、Galloway和Newman的洛伦兹分裂定理纳入一个更接近黎曼几何中Cheeger-Gromoll分裂定理的框架。
We provide a new proof of the splitting theorems from Lorentzian geometry, in which simplicity is gained by sacrificing linearity of the d'Alembertian to recover ellipticity. We exploit a negative homogeneity (non-uniformly) elliptic $p$-d'Alembert operator for this purpose. This allows us to bring the Eschenburg, Galloway, and Newman Lorentzian splitting theorems into a framework closer to the Cheeger-Gromoll splitting theorem from Riemannian geometry.
探测下一次银河系核心坍缩超新星中的引力波记忆
Colter J. Richardson, Haakon Andresen, Anthony Mezzacappa, Michele Zanolin, Michael G. Benjamin, Pedro Marronetti, Eric J. Lentz, Marek J. Szczepanczyk
AI总结 提出结合线性预测滤波和匹配滤波的方法,利用当前干涉仪探测银河系核心坍缩超新星中的线性引力波记忆,可在10 kpc距离内实现探测,并给出与中微子探测兼容的虚警概率。
我们提出了一种利用当前干涉仪探测银河系核心坍缩超新星中(线性)引力波记忆的方法。引力波记忆是广义相对论的一个重要预测,尚未被证实。我们的方法结合了线性预测滤波和匹配滤波。我们展示了该方法在一系列前身星质量和金属丰度的核心坍缩超新星模拟数据上的结果。我们能够探测到10 kpc距离处的引力波记忆。我们还给出了与中微子探测存在的On-Source窗口兼容的虚警概率。勘误:用于展示所提出的引力波记忆探测方法有效性的总波形中的中微子诱导引力波形计算有误。它们被低估了$4\pi$倍。因此,探测结果有所改善,最重要的是,我们的主要结论得到了加强。特别是,使用修正后的波形(见图1和图3),D9.6-3D信号实际上在1千秒差距处是可探测的(见图6和图4)。修正后的拟合参数见表1。所有三个信号的虚警概率都受到影响,如图5所示。图5表明,我们提出的方法可以可靠地探测到1 kpc处所有截止值的D9.6-3D信号,但关于无法在10和100 kpc处探测到该信号的结论保持不变。我们观察到D15-3D和D25-3D信号的可探测性有所提升。现在我们在10和100 kpc处获得了更低的虚警概率。作者感谢Lella等人[87]指出我们计算的中微子诱导波形与他们的不一致,这促使我们调查差异并发现了我们的错误。
We present an approach to detecting (linear) gravitational wave memory in a Galactic core-collapse supernova using current interferometers. Gravitational wave memory is an important prediction of general relativity that has yet to be confirmed. Our approach uses a combination of Linear Prediction Filtering and Matched-Filtering. We present the results of our approach on data from core-collapse supernova simulations that span a range of progenitor mass and metallicity. We are able to detect gravitational wave memory out to 10 kpc. We also present the False Alarm Probabilities assuming an On-Source Window compatible with the presence of a neutrino detection. Errata: The neutrino-induced gravitational waveforms, a component of the total waveforms used to demonstrate the efficacy of the proposed detection method for gravitational wave memory, were computed incorrectly. They were underestimated by a factor of $4\pi$. As a result, the detection results improve and, most important, our primary conclusions are reinforced. In particular, with the corrected waveforms, see Fig. 1 and Fig. 3, the signal for D9.6-3D is in fact detectable at 1 kiloparsec, see Fig. 6 and Fig. 4. The corrected fit parameters are presented in Table 1. The false alarm probability for all three signals is impacted, as shown in Fig. 5. Fig. 5 demonstrates that our proposed method can reliably detect the D9.6-3D signal at 1 kpc for all cutoff values, but our conclusions regarding the inability to detect this signal at 10 and 100 kpc remain the same. We see a boost in the detectability of the D15-3D and D25-3D signals. We now obtain a lower false alarm probability at 10 and 100 kpc. The authors would like to acknowledge Lella et al. [87] for pointing out the discrepancy between our computed neutrino-induced waveforms and theirs, which prompted us to investigate the discrepancy and which led to the discovery of our error.
促进排斥过程的混合时间
James Ayre, Paul Chleboun
AI总结 研究一维促进排斥过程在区间和圆环上的混合时间,通过高度函数构造与排斥过程的耦合,证明对称情形混合时间阶为N²log(N-k)并出现预截止现象,非对称情形可达指数慢混合。
促进简单排斥过程(FEP)是一种具有动力学约束的一维排斥过程。我们建立了在具有封闭边界的区间和圆环上FEP混合时间的界。这些空间上的FEP表现出瞬态:如果粒子的宏观密度至少为$1/2$,过程最终会退出并到达一个遍历分量;如果宏观密度小于$1/2$,过程将击中一个吸收态。我们证明,在区间$\{1,\ldots,N\}$上,具有$k>N/2$个粒子的对称FEP(SFEP)的混合时间阶为$N^{2}\log(N-k)$,并表现出预截止现象。对于区间上的非对称FEP(AFEP),我们证明存在初始条件使得击中遍历分量的时间在空位数$N-k$上指数缓慢。特别地,当$N-k$足够大时,击中遍历分量的时间决定了混合时间。对于大小为$N$的圆环上的SFEP,宏观粒子密度$\rho \in(1/2,1)$,我们建立了限制在其遍历分量上的过程混合时间的界,阶为$N^{2}\log N$。我们还对一大类初始条件给出了击中遍历分量的时间上界,阶为$N^{2}\log N$。证明依赖于通过FEP的一种新的格点路径(高度函数)构造与排斥过程(包括开边界和闭边界)的耦合。
The facilitated simple exclusion process (FEP) is a one-dimensional exclusion process with a dynamical constraint. We establish bounds on the mixing time of the FEP on the segment, with closed boundaries, and the circle. The FEP on these spaces exhibits transient states that, if the macroscopic density of particles is at least $1/2$, the process will eventually exit to reach an ergodic component. If the macroscopic density is less than $1/2$ the process will hit an absorbing state. We show that the symmetric FEP (SFEP) on the segment $\{1,\ldots,N\}$, with $k>N/2$ particles, has mixing time of order $N^{2}\log(N-k)$ and exhibits the pre-cutoff phenomenon. For the asymmetric FEP (AFEP) on the segment, we show that there exists initial conditions for which the hitting time of the ergodic component is exponentially slow in the number of holes $N-k$. In particular, when $N-k$ is large enough, the hitting time of the ergodic component determines the mixing time. For the SFEP on the circle of size $N$, and macroscopic particle density $\rho \in(1/2,1)$, we establish bounds on the mixing time of order $N^{2}\log N$ for the process restricted to its ergodic component. We also give an upper bound on the hitting time of the ergodic component of order $N^{2}\log N$ for a large class of initial conditions. The proofs rely on couplings with exclusion processes (both open and closed boundaries) via a novel lattice path (height function) construction of the FEP.
条带上高自旋顶点模型的平稳测度
Zongrui Yang
AI总结 通过融合矩阵乘积态方法求解条带上高自旋顶点模型的平稳测度,并用Askey-Wilson过程刻画,发现其相图与开放ASEP一致,支持相图普适性。
我们引入了一个在条带上具有融合顶点权重的高自旋顶点模型。该模型可以看作是条带上未融合六顶点模型 (arXiv:2212.09111) 和 arXiv:1711.08884 中引入的“可积两步Floquet动力学”模型的推广。我们使用融合版本的矩阵乘积态方法求解平稳测度,然后用Askey-Wilson过程刻画它。利用这一刻画,我们得到了沿任意右下路径的平均密度的极限。结果表明,所有这些模型共享一个共同的相图,经过适当的映射后,该相图与开放ASEP的相图匹配。这为相图的普适性提供了证据。
We introduce a higher spin vertex model on a strip with fused vertex weights. This model can be regarded as a generalization of both the unfused six-vertex model on a strip arXiv:2212.09111 and an 'integrable two-step Floquet dynamics' model introduced in arXiv:1711.08884. We solve for the stationary measure using a fused version of the matrix product ansatz and then characterize it in terms of the Askey-Wilson process. Using this characterization, we obtain the limits of the mean density along an arbitrary down-right path. It turns out that all these models share a common phase diagram, which, after an appropriate mapping, matches the phase diagram of open ASEP. This provides evidence for the universality of this phase diagram.